Bird Technologies Group 5PI613805 SIGNAL BOOSTER User Manual 9408cvr 1 2

Bird Technologies Group SIGNAL BOOSTER 9408cvr 1 2

USERS MANUAL

Part No.61-38-05 UserMan page 1 of 38Installation and Operation Manual for the Two-Way Signal Booster SystemModel Number 61-38-05First Printing: June 20057-9408-1.2Version Number Version Date1 06/14/051.1 07/12/051.2 07/25/05Copyright © 2005 TX RX Systems Inc.
61-38-05 UserMan page 2 of 38NOTEWARNINGWarrantyThis warranty applies for one year from shipping date.TX RX Systems Inc. warrants its products to be free from defect in material and workman-ship at the time of shipment. Our obligation under warranty is limited to replacement orrepair, at our option, of any such products that shall have been defective at the time ofmanufacture.TX RX Systems Inc. reserves the right to replace with merchandise of equal performancealthough not identical in every way to that originally sold.TX RX Systems Inc. is not liable for damage caused by lightning or other natural disasters.No product will be accepted for repair or replacement without our prior written approval.The purchaser must prepay all shipping charges on returned products. TX RX SystemsInc. shall in no event be liable for consequential damages, installation costs or expense ofany nature resulting from the purchase or use of products, whether or not they are used inaccordance with instructions. This warranty is in lieu of all other warranties, either ex-pressed or implied, including any implied warranty or merchantability of fitness. No repre-sentative is authorized to assume for TX RX Systems Inc. any other liability or warrantythan set forth above in connection with our products or services.Terms and Conditions of SalePRICES AND TERMS: Prices are FOB seller’s plant in Angola, NY domestic packagingonly, and are subject to change without notice. Federal, State and local sales or excisetaxes are not included in prices. When Net 30 terms are applicable, payment is duewithin 30 days of invoice date. All orders are subject to a $100.00 net minimum.QUOTATIONS: Only written quotations are valid.ACCEPTANCE OF ORDERS: Acceptance of orders is valid only when so acknowledgedin writing by the seller.SHIPPING: Unless otherwise agreed at the time the order is placed, seller reserves theright to make partial shipments for which payment shall be made in accordance withseller’s stated terms. Shipments are made with transportation charges collect unlessotherwise specified by the buyer. Seller’s best judgement will be used in routing, exceptthat buyer’s routing is used where practicable. The seller is not responsible for selectionof most economical or timeliest routing.CLAIMS: All claims for damage or loss in transit must be made promptly by the buyeragainst the carrier. All claims for shortages must be made within 30 days after date ofshipment of material from the seller’s plant.SPECIFICATION CHANGES OR MODIFICATIONS: All designs and specifications ofseller’s products are subject to change without notice provided the changes or modifi-cations do not affect performance.RETURN MATERIAL: Product or material may be returned for credit only after writtenauthorization from the seller, as to which seller shall have sole discretion. In the eventof such authorization, credit given shall not exceed 80 percent of the original purchase.In no case will Seller authorize return of material more than 90 days after shipment fromSeller’s plant. Credit for returned material is issued by the Seller only to the originalpurchaser.ORDER CANCELLATION OR ALTERATION: Cancellation or alteration of acknowledgedorders by the buyer will be accepted only on terms that protect the seller against loss.NON WARRANTY REPAIRS AND RETURN WORK: Consult seller’s plant for pricing.Buyer must prepay all transportation charges to seller’s plant. Standard shipping policyset forth above shall apply with respect to return shipment from TX RX Systems Inc. tobuyer.DisclaimerProduct part numbering in photographs and drawings is accurate at time of printing.Part number labels on TX RX products supercede part numbers given within this manual.Information is subject to change without notice.SymbolsCommonly UsedCAUTION orATTENTIONHigh VoltageUse SafetyGlassesESDElectrostaticDischargeHot SurfaceElectrical ShockHazardImportantInformation
61-38-05 UserMan page 3 of 38To satisfy FCC RF exposure requirements for transmittingdevices, a separation distance of 70 Centimeters or moreshould be maintained between the UPLINK antenna of thisdevice and persons during device operation. To satisfy FCCRF exposure requirements for transmitting devices, a sepa-ration distance of 21.5 Centimeters or more should be main-tained between the DOWNLINK antenna of this device andpersons during device operation. To ensure compliance,operations at closer than these distances is not recom-mended.The antenna used for this transmitter must not be co-locatedin conjunction with any other antenna or transmitter.WARNINGFor Class A Unintentional RadiatorsThis equipment has been tested and found to comply with the limits for a Class A digital device, pursuant topart 15 of the FCC rules. These limits are designed to provide reasonable protection against harmful inter-ference when the equipment is operated in a commercial environment. This equipment generates, uses,and can radiate radio frequency energy and, if not installed and used in accordance with the instructionmanual, may cause harmful interference to radio communications. Operation of this equipment in a resi-dential area is likely to cause harmful interference in which case the user will be required to correct theinterference at his own expense.Changes or modifications not expressly approved by TXRX System Inc. could void the user’s authority to operatethe equipment.WARNINGThis device complies with Part 15 of the FCC Rules. Operation is subject to thefollowing two conditions: (1) this device may not cause harmful interference and(2) this device must accept any interference received, including interferencethat may cause undesired operation.
61-38-05 UserMan page 4 of 38Antenna System InstallationThe antenna or signal distribution system consists of two branches. An uplinkbranch typically uses an outdoor mounted, unidirectional gain antenna suchas a yagi and a downlink signal radiating system consisting of a network ofzero-gain whip antennas or lengths of radiating cable usually mounted insideof the structure.Even though the antenna system may not be supplied or installed by TX RXSystems. The following points need to be observed because both the safetyof the user and proper system performance depend on them.1) Antenna system installation should only be performed by qualified techni-cal personnel.2) The following instructions for your safety describe antenna installationguidelines based on FCC Maximum RF Exposure Compliance require-ments.3) The uplink antenna is usually mounted outside and exchanges signalswith the repeater base station or donor site. It is typically mounted perma-nently-attached to the building wall or roof. The gain of this antenna shouldNOT exceed 10 dB. Only qualified personnel should have access to theantenna and under normal operating conditions, no one should be able totouch or approach it within 70 Centimeters (28 inches).4) The downlink or in-building signal distribution system is connected to thedownlink booster port using coaxial cable. The distribution system mayuse radiating coaxial cable or a network 1/4 wave whip antennas whosegain does not exceed 0 dB for any radiator. These antennas should beinstalled so that the user cannot approach any closer than 21.5 Centime-ters (9 inches) from the antenna.
Table of Contents Manual 7-9408-1.2 07/25/0561-38-05 UserMan page 5 of 38Table of ContentsSection 1Introduction ......................................................................................................... 1 Note About Output Power Rating ........................................................................ 3Installation............................................................................................................ 3Cautionary Notes ................................................................................................. 4Pre-RF Connection Tests.................................................................................... 4 Test Equipment ................................................................................................... 5 Antenna Isolation ................................................................................................. 5 Procedure for Measuring Antenna Isolation ........................................................ 5 Increasing Isolation.............................................................................................. 6 Input Signal Levels .............................................................................................. 6 Procedure for Measuring Input Signal Levels...................................................... 6 Reduction of Incoming Signal Strength ............................................................... 8 Setting Signal Booster Gain ................................................................................ 8 Gain Reduction Methods ..................................................................................... 8 Bypassing Amplifier Sections ............................................................................ 9Operation.............................................................................................................. 9Signal Flow........................................................................................................... 9System Components.........................................................................................10 Passive Filtering ................................................................................................ 10 DC Regulator (3-5969) ...................................................................................... 11 OLC Assembly (3-6280) .................................................................................... 11 Pre-amplifier Stage (3-11423) ...........................................................................12 Driver Amplifier Stage (3-11423) ....................................................................... 13 Hi Power Amplifier Assembly (3-11792)............................................................13 Signal Sampler (3-6999).................................................................................... 13 Signal Sampler (3-3569).................................................................................... 13 DC Junction Box (3-6254) ................................................................................. 13 Power Supply Assembly (3-15503) ................................................................... 13Performance Survey.......................................................................................... 14Field Adjustments ............................................................................................. 14 Filter Tuning....................................................................................................... 15 Helical Preselectors........................................................................................... 16 Required Equipment........................................................................................ 16 Tuning Procedure ............................................................................................ 16 Bandpass Filters................................................................................................ 17 Required Equipment........................................................................................ 17 Tuning Procedure ............................................................................................ 17 Pseudo-Bandpass Filters ..................................................................................18 Required Equipment........................................................................................ 19 Tuning Procedure ............................................................................................ 19 Notch Filters ...................................................................................................... 20 Required Equipment........................................................................................ 20 Tuning Procedure ............................................................................................ 21 Single Section Amplifier Subassemblies ........................................................... 22 Amplifier Tuning...............................................................................................22 Required Equipment........................................................................................ 22 Adjustment Procedure ..................................................................................... 23 Output Level Control (OLC)............................................................................... 25 Checking for Overload.....................................................................................25
Table of Contents Manual 7-9408-1.2 07/25/0561-38-05 UserMan page 6 of 38Maintenance and Repair ................................................................................... 26Recommended Replacement Parts ................................................................. 26Conversion Chart .............................................................................................. 26Figures and TablesFigure 1: Front view of typical 61-38-05 system ................................................... 2Figure 2: Bottom view of the cabinet enclosure.................................................... 3Figure 3: Top view of the cabinet enclosure......................................................... 4Figure 4: Measuring antenna isolation ................................................................. 5Figure 5: Measuring input signal levels ................................................................ 7Figure 6: Observing RF power output .................................................................. 8Figure 7: 1 stg/3 stg amplifier assembly 3-11423................................................. 9Figure 8: OLC assembly 3-6280......................................................................... 12Figure 9: Measuring signal booster gain ............................................................ 14Figure 10: Surveying performance .....................................................................15Figure 11: Preselector tuning ............................................................................. 16Figure 12: Observing preselector return loss ..................................................... 17Figure 13: Bandpass filter tuning........................................................................18Figure 14: The pseudo-bandpass filter...............................................................18Figure 15: Tuning for maximum return loss ........................................................19Figure 16: Tuning for maximun attenuation ........................................................ 20Figure 17: The notch filter................................................................................... 20Figure 18: Tuning for maximum return loss ........................................................21Figure 19: Tuning for maximum attenuation ....................................................... 22Figure 20: Mechanical layout of single section amplifier ....................................23Figure 21: Measuring amplifer gain .................................................................... 24Figure 22: Meqsuring input return loss ...............................................................24Figure 23: Measuring output return loss ............................................................. 25Figure 24: Measuring reverse isolation ..............................................................25Specifications .................................................................................................... 33Power Conversion Chart................................................................................... 35Notes................................................................................................................... 38
TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 761-38-05 UserMan page 7 of 38INTRODUCTIONThis publication, Instruction Manual 7-9408-1, con-tains information to support the installation, opera-tion, and maintenance of the model 61-38-05signal booster system. Also included in this manualare the procedures necessary for field adjust-ments. It is assumed that procedures in this man-ual will be carried out by a skilled electronicstechnician who is familiar with the communicationssystem. This manual also gives an elementaryexplanation of the operation of signal boosters andsignal distribution systems. For a more detaileddiscussion of signal booster systems and designmethods, refer to the TX RX Systems Inc. publica-tion "SEMINAR SUBJECTS" entitled "RepeaterAmplifier Systems: Principles and Applications" (lit-erature number C2012J94). Contact your TX RXSystems, sales representative if you wish to ordera copy.The 61-38-05 booster family is designed to coverthe frequency range of 138 to 174 MHz in two noncontiguous bands, One version covers 138 to 144MHz for operation in Canada and another versionto cover 148 to 174 MHz. This version is also usedto cover U.S. land-mobile frequencies from 150.8to 174 MHz. Units for both bands share commonactive circuitry but differ in the passive filter unitsthat duplex the downlink and uplink branches froma common input or to a common output. Becausesignal booster systems are often times subjectedto very demanding environments with extreme con-ditions of temperature, moisture, dirt and corro-sives, the system is housed in a high quality(NEMA style) enclosure. This type of housingmaintains its dimensional stability and appearancebetter than other materials. Figure 1 shows a frontview of the unit with the door opened.The system uses linear RF active amplifiers, filters,OLC (output level control) circuitry, and DC powersources to adequately boost the level of the RF sig-nals. Linear power amplifiers (Class-A) are used inthe amplifier stages of this signal booster system incontrast to the highly efficient Class-C poweramplifiers used in the output stages of most FMlandmobile transmitters. Linear amplifiers arebiased for a relatively high continuous DC currentdrain that does not change with changing RF drivelevels.Class-A amplifiers generally have the lowest effi-ciency of the various amplifier types, typically in therange of 25-33%. They also draw relatively highcurrent levels on a continuous basis, making heatdissipation an important factor. Their biggestadvantage is faithful reproduction of the inputwaveform which results in the lowest levels of inter-modulation distortion products (IM) of all theclasses of amplifiers. IM generation is a seriousdesign consideration when two or more channelsare simultaneously present in the same amplifierstage.Preselector filters are used in the system to providea number of functions including; reduction of thelevel of undesired signals that may enter the sys-tem and also help suppress any IM products thatmay be inadvertently generated. They also pro-duce a convenient impedance characteristic thatallows multiple branch paths to be tied together toa common input/output port. This is accomplishedusing critical length cables from the filter assem-blies to a tee junction.The output level of any signal passing through asignal booster is determined by the input signallevel, the gain of the booster, and the maximumoutput power per carrier rating of the booster. Thehigh power output stages used in the signalbooster may be damaged by excessive input sig-nals. An output level control (OLC) circuit is addedto each amplifier chain to protect the amplifiers andreduce spurious signals. The OLC circuit isdesigned to maintain the maximum output level ofthe booster during times of excessive input signallevels.OLC circuitry actuates when a predetermined max-imum output level is reached. The output powerlevel in all OLC branches is sampled, and then fedto a detector circuit which generates a DC voltageproportional to the output power level. The DC out-put of the detector is then applied to a control cir-cuit which develops a voltage used to control avariable electronic attenuator. The electronicallycontrolled attenuator is placed within the amplifiersignal path and reduces the incoming signal by anamount necessary to keep the power from exceed-ing the maximum safe level. The gain reductionrange is typically from 5 to 40 dB which is morethan adequate for most real life situations.OLC circuitry should not be considered a panaceafor a poor system design. One undesirable affect ofOLC is that the signal level of all signals being pro-cessed by the branch will be reduced when the cir-cuitry is activated. This means that the
61-38-05 UserMan page 8 of 38TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 8Figure 1: Front view of a typical model 61-38-05 signal booster system.Backup Batteryconnects hereFiltering FilteringSignalSampler3-3569SignalSampler3-3569SignalSampler3-6999SignalSampler3-6999OLCAssembly3-6280OLCAssembly3-62801 stg/3 stgAmplifierAssembly3-114231 stg/3 stgAmplifierAssembly3-11423High PowerAmplifierAssembly3-11792High PowerAmplifierAssembly3-11792Regulator3-5969Regulator3-5969Power SupplyAssembly 3-11503RF In/OutputConnector RF In/OutputConnector
TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 961-38-05 UserMan page 9 of 38performance of the system is actually decreasedon all other channels within the branch as long asgain reduction is taking place. This implies thatOLC has been designed to handle short term ortransient overdrive episodes only.Note About Output Power RatingA single maximum output power rating does notapply to broadband signal boosters because thelinear amplifiers (Class A) used in them may haveto process multiple simultaneous signals. Underthese conditions, the questions of power ratingbecomes more complex.When more than one signal is amplified, a numberof spurious signals will also appear in the amplifiedoutput. They are referred to as intermodulation dis-tortion products, more commonly called I.M. Thesespurious products would not be present in a per-fectly linear amplifier but as in all things, somethingshort of perfection is realized. The net result is thatthe total power out in each signal will be somewhatless than the single carrier rating in order to main-tain adequate I.M. performance.INSTALLATIONThe layout of the signal distribution system will bethe prime factor in determining the mounting loca-tion of the signal booster enclosure. However,safety and serviceability are also key consider-ations. The unit should be located where it cannotbe tampered with by unauthorized personnel yet iseasily accessible to service personnel using trou-ble shooting test equipment such as digital multim-eters and spectrum analyzers. Also consider theweight and size of the unit should it becomedetached from its mounting surfaces for any rea-son.Very little is required to install this signal booster.The unit should be bolted in its permanent positionusing lag bolts or other suitable fasteners. Makesure there is an unobstructed airflow over theexternal heatsinks. Safety and serviceability arekey considerations. The signal booster cabinet willstay warm during normal operation so in the inter-est of equipment longevity, avoid locations that willexpose the cabinet to direct sun or areas where thetemperature is continually elevated.The signal booster is designed to be powered from120 VAC and a conduit entry box is provided at thebottom of the enclosure for bringing the AC line intothe cabinet. AC line connections should be made inaccordance with local electrical and building codes.The battery backup system should also be con-Figure 2: Bottom view of cabinet enclosure.
61-38-05 UserMan page 10 of 38TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 10nected at this time. The 3-pin MS style connectorfor the backup power system is labeled and islocated on the bottom of the enclosure. A photo-graph of the bottom of the cabinet is shown in Fig-ure 2.Connection of RF to the unit is made via “N” femaleconnectors located on top of the cabinet. Theseconnectors are individually labeled “High Frequen-cies IN Low frequencies OUT” and “Low Frequen-cies IN High Frequencies OUT”. Care should beused when making connections to these ports toinsure the correct antenna cable is connected to itscorresponding input / output port or the system willnot work. The use of high quality connectors withgold center pins is advised. Flexible jumper cablesmade of high quality coax are also acceptable forconnecting to rigid cable sections. A photograph ofthe top of the cabinet is shown in Figure 3.CAUTIONARY NOTESThe following cautions are not intended to frightenthe user but have been added to make you awareof and help you avoid the areas where experiencehas shown us that trouble can occur.1) Just like the feedback squeal that can occurwhen the microphone and speaker get too close toeach other in a public address system, a signalbooster can start to self oscillate. This will occurwhen the isolation between the input antenna orsignal source and the output antenna or signal dis-tribution system does not exceed the signalbooster gain by at least 10 dB. This condition willreduce the effectiveness of the signal booster andpossibly damage the power amplifier stages.2) The major cause of damage to signal boosters isthe application of input RF power levels in excessof the maximum safe input. This can happen inad-vertently when connecting a signal generator withfull power out to one of the inputs or by a verystrong signal that is far stronger than expected.The Maximum Safe Power input level for your unitcan be found on the laminated tag affixed to the topof the cabinet near the RF input/outputs. Followingthe pre-installation checks listed below will help toavoid these two problems.PRE-RF CONNECTION TESTSCertain characteristics of the signal distributionsystem should be measured before connecting it tothe signal booster. This step is necessary to insurethat no conditions exist that could possibly damagethe signal booster and should not be skipped foreven the most thoroughly designed system. Twocharacteristics need to be measured; antenna iso-lation and input signal levels.Figure 3: Top view of cabinet enclosure.
TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 1161-38-05 UserMan page 11 of 38Test EquipmentThe following equipment is required in order to per-form the pre-installation measurements.1) Signal generator for the frequencies of interestcapable of a 0 dBm output level. Modulation isnot necessary.2) Spectrum analyzer that covers the frequenciesof interest and is capable of observing signallevels down to -100 dBm.3) Double shielded coaxial test cables made fromRG142 or RG55 coaxial cable.Antenna Isolation Antenna isolation is the signal path isolationbetween the two sections of the signal distributionsystem that are to be connected to the signalboosters antenna ports. Lack of sufficient isolationbetween the input and output antennas can causethe amplifiers in the system to oscillate. This canhappen at a high enough level to damage thepower amplifier stages. In general, if one or bothantenna ports are connected to sections of radiat-ing coaxial cable (lossy cable) via short jumpers ofnon-radiating cable the isolation will be more thanadequate because of the high coupling loss valuesthat are encountered with this type of cable. Whena network of antennas are used for the input andoutput, this problem is much more likely. Isolationvalues are relatively easy to measure with a spec-trum analyzer and signal generator.Procedure for Measuring Antenna Isolation1) Set the signal generator for a 0 dBm outputlevel at the center frequency of one of the signalboosters passbands.2) Set the spectrum analyzer for the same centerfrequency and a sweep width equal to or justslightly greater than the passband chosen instep one.3) Connect the test leads of the signal generatorand the spectrum analyzer together using afemale barrel connector, see Figure 4. Observethe signal on the analyzer and adjust the inputattenuator of the analyzer for a signal level thatjust reaches the 0 dBm level at the top of thegraticule. INTERNALSIGNAL DISTRIBUTIONSYSTEMSPECTRUMANALYZEREXTERNALANTENNASIGNALGENERATORZERO LOSSREFERENCEISOLATION (dB)Figure 4: Typical test equipment setup for measuring antenna isolation.
61-38-05 UserMan page 12 of 38TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 124) Referring to figure 4, connect the generator testlead to one side of the signal distribution system(external antenna) and the spectrum analyzerlead to the other (internal distribution system)and observe the signal level. The differencebetween this observed level and 0 dBm is theisolation between the sections. If the signal istoo weak to observe, the spectrum analyzer'sbandwidth may have to be narrowed and itsinput attenuation reduced. Record the isolationvalue. The isolation value measured shouldexceed the amplifier gain figure by at least15 dB.It is wise to repeat the procedure listed above formeasuring antenna isolation, with the signal gener-ator set to frequencies at the passbands edges inorder to see if the isolation is remaining relativelyconstant over the complete width of the passband.Also, the procedure should be repeated for each ofthe remaining channels in the system.Increasing Isolation If the measured isolation does not exceed theamplifier gain figure by at least 15 dB then modifi-cation of the signal distribution system is required.Alternately, the gain of the signal booster can alsobe reduced to insure the 15 dB specification is met.If the isolation cannot be increased then theamount of gain reduction required is determined asshown in the following example.Input Signal LevelsExcessive input signal levels can damage the sig-nal booster. Although this problem is less severe inOLC protected branches, strong signals may causesudden reductions in gain and an associateddecrease in the desired output signal strength.Even in the most carefully designed signal distribu-tion systems, unpredictable situations can arisethat can cause this trouble. A few of the more com-mon causes are:a) Unintended signals entering the system. Prima-rily caused by radios operating on channels thatare within the operational bandwidth of the sig-nal booster. Sometimes this will be a transientproblem caused by mobile units when theytransmit while in close proximity to your system.b) Hand-held and mobile units that approachmuch closer than expected to one of the anten-nas in the signal distribution system.c) Unexpected signal propagation anomalies.Building geometry can cause signal ducting andother phenomena that cause signal levels thatare much stronger (or lower) than expected.d) Lower than estimated signal attenuation causessignals to be unusually strong. Higher lossescan also occur giving weaker signals thandesired.e) Signal booster model with excessive gain. Insystems that have an existing signal booster, itis sometimes assumed that an identical unitshould be installed when expanding the systemto provide extended coverage. In most cases, asignal booster with far less gain than the first isrequired.f) Improper installation or application of signalsplitters or directional couplers in the signal dis-tribution system. This is usually the cause of toolow a signal level but deserves mentioning here.Signal splitting needs to be done with constantimpedance signal splitters so that the properpower splitting ratios and VSWR are main-tained. Using tee connectors by themselves isinviting trouble. Directional couplers must beconnected with regard to their directionality andcoupling levels or improper system signal levelsmay result.Procedure for Measuring Input Signal Levels 1) Set a spectrum analyzer for the center fre-quency of one of the branches (look at thespecification drawing for this information).2) Set the analyzer sweep width so that the entirepassband frequency range can be observed.EXAMPLEGain Reduction (dB) = Minimum Isolation (dB) - Measured Isolation (dB)If the measured isolation is -75dB and the mini-mum isolation is -80dB then the amount of gainreduction required is: -80dB - (-75) = -5 dB
TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 1361-38-05 UserMan page 13 of 383) The analyzer input attenuator should be set toobserve input signal levels from approximately -80 dBm to 0 dBm.4) Connect the analyzer to the section of the sig-nal distribution system that is going to serve asthe input for the branch you want to observe(see Figure 5).5) Record the power level (in dBm) of all carriers inthe passband frequency range that are signifi-cantly greater than the noise floor displayed onthe analyzer.6) Repeat steps 1 through 5 for the remaining sig-nal booster channels.7) To find the total power being applied to thechannel, the calculations listed below must beperformed. The conversion chart at the rear ofthe manual can be used. Here are the steps:a) Convert all values in dBm to Wattsb) Total the power for all carriers in Wattsc) Convert the total power in Watts to dBmRepeat the calculation for all of the branches in thesystem. For example: suppose we have a signalbooster with a maximum gain of 70 dB. Afterchecking the input signal levels, it was determinedthat there are three signals that are significantlygreater than the noise floor displayed on the ana-lyzer. These signals have strengths of -45 dBm, -43 dBm and -41 dBm. First we use the conversion chart at the end of thismanual to convert the power levels in dBm to wattsso that we can add them together. The power inwatts is written in scientific notation but the chartuses computer notation. For example, in the chart,an exponent may be written as E-08. In conven-tional mathematical notation E-08 is written 10-8.The total power must be written as a numberbetween 0 and 10 to use the chart. Look up1.611E-7 in the Watts column. This number fallsbetween -38 and -37 dBm so we chose -37because it is the next higher value.Power (dBm) Power (watts)-45 dBm 3.16 x 10-8-43 dBm 5.01 x 10-8-41 dBm 7.94 x 10-8TOTAL 16.11 x 10-8S p e c t r u m A n a l y z e rR a d i o 1R a d i o 2S I G N A L D I S T R I B U T I O N S Y S T E MFigure 5: Typical test equipment setup for measuring input signal levels.
61-38-05 UserMan page 14 of 38TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 14Reduction of Incoming Signal StrengthReducing the strength of offending signals mayrequire some or all of the following steps:a) The addition of extra filtering. Consult TX RXSystem's sales engineers for help in thisrespect.b) Modification of the signal distribution layout bychanging the type or location of pickup anten-nas. This has to be approached in an empiricalway, that is, change-and-try until you get thedesired results. Sometimes changing from omnito directional antennas will correct the problem.Setting Signal Booster GainThe Pre-Installation checks as outlined earliershould have been performed to determine if gainreduction will be necessary for your installation.This can be due to low antenna isolation or exces-sive input signal levels, or both. The actual amountof gain reduction is determined by the largest num-ber required because of either low isolation orexcessive signal levels.For example, if the results of the isolation measure-ment indicated the need for a gain reduction of -10dB but signal level measurements indicate a needfor only a -5 dB gain reduction; then 10 dB is thenumber required since both conditions are satis-fied.Gain Reduction MethodsAs shipped from the factory, the system was setupfor maximum gain. Gain reduction is accomplishedby adding fixed attenuator pads or where evengreater reductions are required by bypassing onesection in a multi-section amplifier stage. Bypass-ing of amplifier sections is preferred for large gainreductions so that excessive noise levels are notproduced. Use of attenuator pads alone will reducegain but the signal booster will also amplify thenoise generated in the lower level sections.The addition of attenuator pads may be necessaryin order to achieve the proper signal levels in theoverall communications system. This is quite com-mon as actual signal losses in a radiating cablesystem can vary somewhat from predicted theoret-ical values. Fine adjustment of gain in communica-tions systems with cascaded signal boosters canbe very important to keep performance uniformover the entire length of the system.Figure 6 shows the use of a spectrum analyzer tomonitor signal levels in a signal booster. The ana-lyzer connects to the signal sampler on the outputend of the branch to be tested. Attenuation is thenadjusted for the proper signal levels factoring in theRF from Antenna orPrevious Repeater AmplifierSignal Distribution SystemFilterFilterDCSamplerVariableAttenuatorSpectrumAnalyzer10 dB PadAmpFigure 6: Observing RF power output of a signal booster using a spectrum analyzer.
TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 1561-38-05 UserMan page 15 of 38-50 dB coupling loss of the signal sampler and anyadditional loss produced by attenuator pads on theanalyzer input. A pad on the analyzer input canhelp to minimize measurement errors due toVSWR mismatch that occurs with some analyzers. A pair of fixed attenuator pads (3 and 6 dB) aresupplied for the purpose of gain reduction. Theyare mounted in clips to the top of the filter assem-blies in the center of the unit. The pads’ attenuationvalues are clearly labeled on the body of the atten-uator. The correct position for adding fixed pads tothe system is at the input or output of the electronicattenuator ports on the OLC assembly (shown asthe dotted outline symbols on the specificationdrawing).CAUTION: Any fixed attenuator padsthat are already connected into thebooster circuitry have been installedat the factory and should not beremoved for any reason. Their func-tion may be other than gain reduc-tion.BYPASSING AMPLIFIER SECTIONSSometimes the amount of gain reduction needed isgreater than the amount available with the fixedattenuator pads alone. In this case, the first stageof the three stage portion of amplifier assembly (3-11423) in the uplink or downlink branch may bebypassed. The individual stages of these multi-stage amplifiers are connected together with shortlengths of coaxial cable. To bypass the first stage ofthe driver amp remove the coax cable that inter-connects the first and second stages of the driveramplifier (see Figure 7). Move the input cable fromthe input connector on the first stage to the corre-sponding connector on the second stage of thedriver amp. The BNC RF input connector for eachamplifier stage is located furthest from the DCinput TNC connector. Keep in mind that the totalgain reduction is the sum of the added paddingplus the loss of gain for the bypassed amplifier sec-tion. Quality 50 ohm terminations should beinstalled on the open terminals of any bypassedstage.OPERATIONIt is imperative that the pre-installation checks beperformed as outlined earlier. Failure to do so maylead to unsatisfactory operation or damage to thesignal booster. All that is required in order to putthe system into operation after the installation is toturn on the power supply assembly. The green LEDon the power supply will illuminate indicating nor-mal operation. If the red LED on the power supplyassembly illuminates it indicates operation from thebackup power source.SIGNAL FLOWSignal flow through the system is illustrated usingthe system block diagram that is shown in specifi-cations drawing shipped with your system. The 61-38-05 model signal boosters are composed of 2branches, uplink and downlink. Because the uplinkPre-Amp(Single Stage)Driver Amp(3 Cascaded Stages)RFOutputRFInputRFOutputRFInputFigure 7: 1stg/3stg amplifier assembly 3-11423.
61-38-05 UserMan page 16 of 38TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 16and downlink branches are physically identical,both being constructed from the same set of sub-assemblies, the signal flow discussion that followsis applicable equally well to both branches. Theonly difference between the two branches is thetuning of their passbands.Signals enter the system through the RF connec-tors at the top of the cabinet. This is where the cus-tomers antenna system is interfaced to the booster.Input signals are immediately passed through pas-sive filtering. The filter configurations can varyslightly depending on the exact model of booster.The filters provide the necessary isolation to allowa pair of amplifier chains to be tied together provid-ing bi-directional amplification with a single com-mon input and common output connection. Asecondary but very beneficial effect of filtering isinstantaneous input and output frequency spec-trum limiting which helps to prevent amplification ofunwanted channels. After filtering signals are thenapplied to a preamplifier stage (the first section ofthe multi-stage amplifier assembly 3-11423).Following the preamplifier signals are applied tothe input of OLC (output level control) assembly 3-6280. This assembly will attenuate the incomingsignals if necessary, to protect the final amplifierfrom being overdriven by stronger than usual inputsignals. The amount of attenuation is determinedby a reference voltage produced by a detector cir-cuit built into the OLC assembly, which continu-ously samples the output level of the final amplifier.Once past the OLC assembly the signals areapplied to a driver amplifier composed of the finalthree sections of the multi-stage amplifier assem-bly 3-11423. The driver amplifier ensures that sig-nals applied to the next stage, the final amplifier,are at their optimum level and as free of any inter-modulation distortions as possible. The high poweramplifier 3-11792 is a linear amp operated at con-siderably less than it’s maximum output power toinsure maximum linearity.Signals output from the high power amplifier stageare routed to the detector input of the OLC assem-bly by the first signal sampler 3-6999. The purposeof the detected signal is to adjust the amount ofattenuation provided by the OLC assembly to theincoming signal after the preamplifier stage. Theoutput of the high power amplifier is passedthrough a second signal sampler 3-5969 that pro-vides a -50 dB sampled signal as a convenience forservice technicians. The signals then pass throughpassive filtering before leaving the signal booster atthe output connector located on the top of the cabi-net. This is where the customers antenna system isinterfaced to the booster.SYSTEM COMPONENTSEach of the major system components used in themodel 61-38-05 family of signal boosters are brieflydiscussed in the following text. Refer to the systemspecification drawing that shipped with your systemduring this discussion. The specification drawingwill include complete electrical and mechanicalspecifications for your model. These include fre-quency band, bandwidth, power gain and maxi-mum power ratings. Recommended maximumpower ratings are shown for single signal and multi-ple signal applications.The functional block diagram included on the spec-ification drawing shows all of the major subassem-blies and their interconnections. Part numbers forthe major assemblies are also shown. We suggestyou look this drawing over carefully to fully familiar-ize yourself with the unit.Passive FilteringThe passive filters on the input and output ends ofeach active section have one major purpose: theyprovide the necessary isolation to allow a pair ofamplifier chains to be tied together providing bi-directional amplification with a single commoninput and common output connection. The filtersprovide duplex operation and each one is tuned topass either the downlink or uplink frequency band.They must provide a minimum isolation factor thatexceeds the amplifier gain by 15 dB in order to pre-vent regenerative feedback and maintain spurious-free operation. In the VHF spectrum, these filtersare usually constructed from cascaded coaxialbandpass cavities or multistage helical bandpassfilters. Bandpass filters may be augmented bynotch filters using the same basic resonator style(coaxial or helical). Notching filters allow the filterresponse to be closely tailored to the specific isola-tion requirements for the specific uplink and down-link frequency band separation. Typical VHFfrequency pairs (repeater input/output frequencies= Down/uplink frequencies) vary considerably infrequency separation making flexibility in tailoringthe filter response a necessity for proper operation.When necessary, single channel bandpass filtersmay also be used as an augment to facilitate close-spaced frequency operation without interference.
TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 1761-38-05 UserMan page 17 of 38Single channel bandpass filters are generally 4-pole crystal filters using piezo-electric resonators.A secondary but very beneficial effect of filtering isinstantaneous input and output frequency spec-trum limiting which helps to prevent amplification ofunwanted channels. While filtering can reduce or eliminate spuriousoutput signal, this is a tertiary function in the VHFsignal booster because this booster family usesClass-A linear amplifiers that generate much lowerharmonic content than the typical Class C or Damplifier used in typical landmobile transmitters.The input and output filter assemblies used in themodel 61-38-05 signal booster systems are com-posed of helical preselectors, 2” square bandpasscavities, and 2” square notch cavities. These filtersall have a carefully shaped response curves thatdefine the pass windows for the booster.The helical preselectors are composed of four cas-caded helical cavities. The cavities are intercon-nected with critical length cables to synthesize ashaped response. The bandpass filters pass onenarrow band of frequencies (the passband) andattenuate all others with increasing attenuationabove and below the pass frequencies. The inser-tion loss setting determines the filters selectivityand maximum power handling capability. Insertionloss is set at the factory. The notch filters are usedto notch out a very narrow range of frequenciesand improve the skirt selectivity of associatedbandpass filters.The filters used in the booster are factory pretunedand do not require any adjustment. The filters areeasy to misalign. Being passive devices using sil-ver plated contacts means they requires no mainte-nance and will stay tuned indefinitely unless theyare physically damaged or tampered with. If it issuspected that a filter is out of alignment, we sug-gest returning it to the factory for re-alignment.However, if the necessary test equipment is avail-able then the tuning procedure outlined later in thismanual may be used to put it back on frequency.DC Regulator (3-5969)The DC regulator receives 24.7 VDC from thepower supply assembly through it's input 'TNC'connector. Two regulator assemblies are used, onefor each signal branch in the bi-directional system.each of the regulators provides two different outputvoltages, +15 VDC and +21.7 VDC. A minimal volt-age differential of 3 volts is required between theinput and the output of the 3-5969 regulator inorder to maintain proper operation. The regulatorassembly can provide up to 5 amps of total current.The regulator circuit uses two conventional IC reg-ulator chips. An LM338K is used to produce thefixed 15 VDC, and an LM340K is used for the vari-able output which is factory adjusted to +21.7 VDC.Test jacks (red & black) are available on the regula-tor chassis for measuring the input, fixed-output,and the variable-output voltages. The regulator hasan access hole on the side of it's case for adjustingthe variable-output voltage. A thin blade screw-driver is used to engage a trim-pot type variableresistor R2 which is then rotated until the desiredoutput voltage is obtained. Adjustment of the regu-lator is only required after making repairs to theregulator circuitry.OLC Assembly (3-6280)The OLC assembly 3-6280 is used in bothbranches of the system is divided into threeshielded compartments; one housing the RF to DCconverter, the second a DC control circuit, and thethird containing the PIN diode attenuator circuit. Atest point is provided for measuring the voltage thatis applied to the PIN diode attenuator. A secondtest point allows measurement of the voltage sup-plied by the converter to the DC control circuit (seeFigure 8). Regulated 21.7 VDC is supplied to the"TNC" female connector to power the assembly.The RF to DC converter receives RF from the sig-nal sampler and produces a negative polarity DCoutput voltage that is proportional to the RF signal.A Schottky Barrier diode is used as the detector.Because this detector circuit has a very high inputimpedance, the magnitude of the voltage that itproduces will vary if the length of the coaxial cablewhich connects it to the signal sampler changes.Therefore, it is important not to change this length.The voltage produced by the RF to DC converter isdirectly proportional to the output signal strength ofthe final amplifier. The voltage is supplied to the DCcontrol circuit at the non-inverting terminal of op-amp IC2. A variable reference voltage is applied tothe inverting terminal of the same op-amp. Variableresistor VR2 is used to set the magnitude of thisreference voltage and controls the level at whichgain reduction will start to occur. As the signalstrength increases the output voltage of the con-verter, which is of negative polarity, becomes
61-38-05 UserMan page 18 of 38TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 18larger. This change causes the output of IC2 toalso become increasingly negative. This outputvoltage is connected via diode D1 to bias the PINdiode attenuator. As this voltage becomes morenegative, the attenuation is increased thus achiev-ing a certain range of gain control. Diode D1insures that the gain control voltage is always posi-tive and never goes below 0 volts. In actual opera-tion, OLC operation is set to commence when thepower output of the final amplifier reaches its maxi-mum two-carrier level as shown on the specifica-tion drawing.Two other IC’s are mounted on the DC control cir-cuit board. IC1 is a 10 volt regulator that suppliesDC to the other two chips. Variable resistor VR1 isused to set this voltage. IC3 is a voltage inverterthat produces -4.5 volts which is applied to the op-amp IC2. This negative bias allows the output volt-age of IC2 to closely approach 0 volts.The PIN diode attenuator board has two diodesthat are used in series to extend the attenuationrange. The diodes are always forward biased withminimum forward resistance and insertion lossoccurring at about 20 ma of current.Pre-Amplifier Stage (3-11423)The pre-amplifier consists of the 400 milliwattamplifier stage connected to the input of the OLCassembly. The preamp is the first stage of the fouridentical stages found in the amplifier assembly 3-11423. This amplifier stage is used to insure that asufficient signal level is applied to the OLC assem-bly.The 1-section/3-section amplifier assembly (3-11423) is composed of four individual and identicalamplifier sections. Each of the individual sections(part# 3-8089) are complete 400 milliwatt amplifi-ers. The individual sections are mounted on a com-mon mounting panel and have a common DCdistribution bus running internally between them.Each section provides 18.5 dB of gain with a powerrequirement of 21.7 VDC (nominal) and a typicalcurrent draw of 121 ma. The maximum single car-rier power output is 400 milliwatts.Each 400 milliwatt amplifier section consists of twocircuits, the amplifier circuit (3-8087) and the biasregulator circuit (3-10742). Both of these circuitsare housed in their own enclosures which are thenphysically joined together to make up one section.The circuits are electrically joined using feed-thrucapacitors Cf1 and Cf2. The amplifier circuit uses a linear RF transistor Q1(Phillips part# BFQ34/01) which is operated in aclass "A" configuration in order to keep any inter-modulation distortion to a minimum. The RF tran-sistor is biased for a nominal collector current of121 ma. A bias regulator circuit is used to keep thecollector current constant with changes in tempera-ture. Narrow band matching techniques are used inthis amplifier and it will require tuning if the transis-tor or matching network components are replaced.CONTROLVOLTAGE+15 VDCOUTPUT INPUTOLC VoltageAdjust10V RegulatorAdjustRF fromSamplerDetectorVoltageTest PointOLCVoltageTest PointRF to DCConverterPin DiodeAttenuatorFigure 8: OLC assembly 3-6280.
TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 1961-38-05 UserMan page 19 of 38The bias regulator circuit uses an Op-Amp compar-ator IC1 to supply a variable bias current which var-ies as required to keep the RF transistors collectorcurrent constant. Current to the collector of the RFtransistor flows through resistor R1. The voltage atthe collector side of this resistor is applied to thenon-inverting input of IC1. Voltage divider R2 / R4sets the desired reference voltage on the invertingterminal of IC1. The variable output voltage at pin 6of IC1 is then applied to the base of the RF transis-tor. The bias on the RF transistor will now vary insuch a way as to keep the voltage at the collectorend of R1 equal to the reference voltage providedby divider R2/R4, thus keeping the RF transistor'scollector current constant (121 ma nominal).Repair or replacement of bias circuit componentsdoes not necessitate retuning of the amplifier.Driver Amplifier Stage (3-11423)The remaining three stages of the amplifier assem-bly 3-11423 are used to form a driver amplifierwhich amplifies the passband signals to levels suf-ficient for driving the input of the final High PowerAmplifier stage. Each of the three individual 400milliwatt stages in the driver amp are identical andwere discussed in detail in the earlier sub-sectionentitled "Pre-Amplifier (3-11423)".High Power Amplifier Assembly (3-11792)This amplifier stage uses a single ultra-linear RFtransistor. The 3.0 watt rating indicates the maxi-mum safe output from this amplifier assemblyusing a single carrier. The actual maximum allow-able power output with multiple carriers is muchlower and is determined by the maximum allowableintermodulation product level. It is also limited bythe collector to emitter breakdown rating of the RFtransistor.This amplifier stage is physically mounted to theinside of the heatsink located on the side of thecabinet. The amplifier draws a nominal 420 ma. Abias regulator circuit within the amplifier assemblyis used to keep the collector current of the RF tran-sistor constant with changes in temperature. Thisamplifier has a minimum gain of 18 dB, 19 dB typi-cal. The amplifier uses narrow band matching tech-niques and will require tuning if the transistor ormatching network components are replaced.Signal Sampler (3-6999)Following the output of the power amplifier assem-bly is a -25 dB signal sampler. This sampler is usedto couple the output signal level back to the OLCassembly.Signal Sampler (3-3569)This sampler is located at the output of the uplinkand downlink branches and is used for connectingtest equipment to the branch, such as a spectrumanalyzer. The 3-3569 signal sampler capacitivelycouples signals to the sample port at a -50 dBlevel.DC Junction Box (3-6254)This assembly has no internal components and isused to couple battery backup voltage (supplied bythe customer) to the power supply.Power Supply Assembly (3-15503)The power supply assembly consists of two sub-assemblies, an OEM power supply module and afailure switching circuit. The switching circuit isdesigned to pass the output from either the OEMpower supply or the backup batteries to the TNCstyle output connectors which are labeled “24.7VDC Output” located on the assemblies front panelnext to the fuses.The output of the OEM supply (part# 8-15495) isapplied to the output TNC connectors through relayK2 pins 9 and 10. The voltage feed is protected byfuse F1 (10 amp). During normal operation relayK2 is energized connecting pin 9 to pin 10. If ACpower is interrupted relay K2 becomes de-ener-gized connecting pin 9 to pin 8 which is fed fromthe battery backup. This will pass battery voltage tothe output TNC connectors.With AC voltage applied to relay K2 pin 6 will beconnected to pin 7 completing the ground path forthe green LED D2. When K2 is de energized indi-cating AC power failure pin 5 is connected to pin 6completing the ground path for the red LED D1indicating the unit is operating on DC backup volt-age.The Loss of AC Alarm Terminal block is providedfor customer convenience. Under normal systemoperation, when the OEM supply voltage is active,the NC terminal is shorted to the COM terminalbecause pins 5 and 6 are connected by relay K1.K1 is energized whenever the AC power supply isactive. When the system is running on batterybackup voltage the NO terminal is connected to theCOM terminal because pin 5 will now be con-
61-38-05 UserMan page 20 of 38TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 20nected to pin 4. Relay K1 is de-energized when theAC power supply is off.PERFORMANCE SURVEYIt is a good idea to document the performance ofthe system after installation so that a referenceexists for future comparisons. This information canmake troubleshooting an interference problem orinvestigation of a complaint about system perfor-mance much easier. If there are coverage prob-lems with a system, this survey will usually revealthem allowing corrective measures to be takenbefore the system is put into routine use. The fol-lowing is an outline of how to do such a survey.Because the nature of each installation can bequite different, only a broad outline is given.1) Measure the gain of the signal booster beingcareful not to exceed the maximum input level.Figure 9 shows this being done using a signalgenerator and spectrum analyzer. This is basi-cally a substitution measurement. Record themeasured values for each passband.2) Each branch of the signal booster system isequipped with a -50 dB signal sampler port fol-lowing the final output amp (part of the OLCassembly). This port is for the connection of testequipment such as a spectrum analyzer andwill allow the observation of the amplifier outputat a considerably reduced output level. Thisdecoupling figure needs to be added to a mea-sured signal value in order to arrive at the actualsignal level. OLC assemblies appear in sche-matic representation on the specification draw-ings.3) With a spectrum analyzer connected to the sig-nal sampler port for the branch under test (seeFigure 10), have personnel with handheldradios move to predetermined points and keytheir radios. Record the level of these signals asobserved on the analyzer and also record thelocation of the person transmitting. In this way, amap of the systems performance can be gener-ated.4) For branches that amplify signals coming from afixed antenna or station, record the level of allthe desired incoming signals for future refer-ence.FIELD ADJUSTMENTSThe following information is provided in support offield support activities, including routine mainte-nance, repairs, adjustments and tuning. It isDCSampler SamplerDetectorElectronicAttenuatorOLC AssemblyFilter FilterAmpDCControlZEROREFERENCEGAIN10 dB PadSIGNALGENERATORSPECTRUMANALYZERFigure 9: Test equipment interconnection for measuring signal booster gain.
TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 2161-38-05 UserMan page 21 of 38assumed that the procedures will be carried out bya qualified electronics technician observing allstandard safety practices.Filter TuningFilters used in TX RX Systems’ signal boosters arepassive devices of rugged electrical and mechani-cal design. They are tuned at the factory for theoriginal design requirements and require no adjust-ment or maintenance. These devices will stay prop-erly tuned unless they have been physicallydamaged or are tampered with. Filter tuning fallsinto two categories; retuning to the original fre-quency such as when a filter is being repaired orreplaced, or tuning to new frequencies.A number of points need to be considered beforeattempting to tune a signal booster to frequenciesdifferent from the original.1) The Frequency Range Specification for the 61-38-05 signal booster family does not mean thatan individual signal booster is field tunable overthe entire indicated frequency range. This spec-ification only indicates the frequency range forwhich the 61-38-05 components are intended.Many of the filter assemblies used in a particu-lar booster maintain reasonable performanceover a range that is within ± 2% of the originalfrequency. For greater changes in frequency,the performance of the filters may degradeseverely. Therefore some filters may need to bereplaced or modified when large frequencychanges are made.2) In a bidirectional system, will the new inboundand outbound channels have the same fre-quency separation from each other as the origi-nal ones? Frequency separation in bidirectionaldesigns is one of the prime design criteria. If thefrequency separation decreases from the origi-nal, the filters will provide less isolation so thegain may also have to be reduced to prevent thesignal booster from oscillating. Increases in fre-quency separation are more easily accommo-dated.3) If the bandwidth requirement increases, thebandpass filters may not pass all of the new fre-quencies. In most cases, the bandwidth of thebandpass filters cannot be changed by the cus-tomer. DCSampler SamplerDetectorElectronicAttenuatorOLC AssemblyFilter FilterAmpDCControl10 dB PadSPECTRUMANALYZERSIGNAL DISTRIBUTION SYSTEMBOOSTEDRF SIGNALFigure 10: Test equipment interconnection for surveying performance.
61-38-05 UserMan page 22 of 38TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 224) The amplifier assemblies may have to beretuned. 5) The length sensitive interconnect cables mayneed to be changed.If you are not sure about tuning the signal boostersystem to new frequencies then contact your TXRX Systems, Inc. representative. Our knowledge-able engineering and sales staff are happy to dis-cuss what it will take to tune your system to thenew frequencies.Helical PreselectorsThe helical preselectors are composed of four cas-caded individual helical cavities. The cavities areinterconnected with critical length cables to synthe-size a shaped response. This filter assembly cannot be tuned by tuning the individual cavities, theassembly must be tuned as a whole. The band-width of the filter is determined by the critical align-ment of internal “reactive” components. Bandwidthis therefore fixed by construction in this type of filterThe helical preselectors are pretuned at the factoryfor a specific bandwidth and no attempt should bemade to adjust the bandwidth.REQUIRED EQUIPMENTA two channel network analyzer that simulta-neously displays both transmission and reflectionis best for properly tuning a preselector. A singlechannel tracking generator / spectrum analyzercombination may be adequate but insure that it isaccurate enough to verify factory specifications. Areturn loss bridge would also be required whenusing a tracking generator / spectrum analyzer.Skill and experience are also needed and the per-sonnel doing the work should be thoroughly famil-iar with the test equipment.TUNING PROCEDUREThe following is an outline of the general proce-dure.1) Connect test equipment as shown in Figure 11.2) Set the analyzer to the desired center fre-quency and desired bandwidth.3) Loosen the tuning rod locking nuts.4) If the preselector is severely out of tune, set theanalyzer for 10 dB/div vertical scale and alter-nately adjust the tuning rods in pairs workingfrom the center to the end rods for maximumsignal at the center frequency. Start with thecenter rods and then move to the outer rods.5) Repeat step 4 tuning to maximize the signal atthe center frequency. The response should startto take on the desired shape and symmetry.Setup the analyzer for 2 dB/div and then re-adjust the rods in the same fashion. Make surethat the response is relatively symmetrical. Fineadjust the tuning rods as necessary to adjustsymmetry.6) When using the spectrum analyzer/trackinggenerator, the equipment must be connected asshown in Figure 12 in order to check the returnloss curve. The network analyzer will show thereturn loss curve as a matter of course.7) Lock all tuning rods after the desired responseis obtained. Note that a slight dissymmetry inAnalyzerInputGenerateOutput+30+40+20+100-10-20-30-404 Section Helical PreselectorFigure 11: Preselector tuning.
TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 2361-38-05 UserMan page 23 of 38either the transmission or reflection responsemay be unavoidable.Bandpass FiltersThe bandpass filters pass one narrow band of fre-quencies (the passband) and attenuate all otherswith increasing attenuation above and below thepass frequencies. The insertion loss setting deter-mines the filters selectivity and maximum powerhandling capability. Insertion loss is set at the fac-tory.Cavity tuning follows a two step process. First thecavity is temporarily disconnected from the systemand rough tuned, this will ensure the responsecurve is very close to it's ideal. Next the cavity isreconnected to the system and fine tuned. This isdone in large systems such as the model 61-38-05in order to eliminate any slight distortions whichcould result from interactions with other cavities.The pass frequency is the only field adjustableparameter found in the individual Bandpass reso-nant cavity filters. Adjustment of the tuning rod onthese filters will allow the passband to be centeredat the desired frequency. The insertion loss of eachcavity is not field adjustable.REQUIRED EQUIPMENTDue to the sensitivity of the adjustments, it isstrongly recommended that the proper equipmentbe used when tuning the individual filters, other-wise the filter should be sent to the factory or anauthorized representative for retuning. The follow-ing equipment or it's equivalent is recommended inorder to properly perform the tuning adjustments.1. IFR A-7550 spectrum analyzer with optionaltracking generator installed.2. 7/16” wrench.3. Double shielded coaxial cable test leads(RG142 B/U or RG223/U).4. Female union (UG29-N or UG914-BNC).TUNING PROCEDUREThe following is an outline of the general proce-dure.1. Turn off the system power and disconnect thecables that are attached to the cavity. 2. Setup the analyzer / generator for the desiredfrequency and bandwidth (center of display)and also a vertical scale of 2 dB/div. Set thesweep width of the display to 100 KHz.4. A zero reference must first be established at theIFR A-7550 before making measurements. Thisis accomplished by temporarily placing a"female union" between the generator outputand the analyzer input.5. The flat line across the screen is the generator'soutput with no attenuation, this value willbecome our reference value by selecting the4 Section Helical PreselectorAnalyzerInputGenerateOutput+30+40+20+100-10-20-30-40Bridge50 ohm LoadFigure 12: Observing preselector return loss.
61-38-05 UserMan page 24 of 38TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 24"MODE" main menu item and choosing the"STORE" command. This will store the flat-linevalue in the analyzer's internal memory.6. Next select the "DISPLAY" main menu item andchoose the "REFERENCE" command. This willcause the stored value to be displayed on thescreen as the 0 dB reference value.7. The resonant frequency of the filter is checkedby connecting the tracking generator to theinput of the cavity filter assembly while thespectrum analyzer is connected to the output,as shown in Figure 13. 8. Insure the IFR A-7550 menu's are set as fol-lows:DISPLAY - lineMODE - liveFILTER - noneSETUP - 50 ohm/dBm/gen1.9. Adjust the pass frequency by setting the peak(minimum loss value) of the response curve tothe desired frequency (should be the center-vertical graticule line on the IFR A-7550's dis-play). The resonant frequency is adjusted byadjusting the tuning rod, which is a slidingadjustment (invar rod) that rapidly tunes the fil-ter's response curve.Pseudo-Bandpass FiltersThe pseudo-bandpass filter passes a relatively nar-row band of frequencies and rejects (notches out)a relatively wide frequency band. These cavity fil-ters are two inch square, helical type resonatorsthat include a tunable notching section, refer toFigure 14. These filters are pretuned and requireno adjustment unless they have been damagedand repaired or tampered with in some way. Theyare passive devices that require no maintenance. Female UnionUsed to determine 0 dB referenceAnalyzerInputGenerateOutput+60+80+40+200-20-40-60-80Tracking Generator2" Sq. BandpassCavity FilterFigure 13: Bandpass filter tuning.Sliding MainTuning Rod(Passband)Main TuningLock NutRejectionNotch TuningCapacitorInput/OutputConnectorsFigure 14: The Pseudo-bandpass filter.
TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 2561-38-05 UserMan page 25 of 38REQUIRED EQUIPMENTDue to the sensitivity of the adjustments, it isstrongly recommended that the proper equipmentbe used when tuning the individual filters, other-wise the filter should be sent to the factory or anauthorized representative for retuning. The follow-ing equipment or it's equivalent is recommended inorder to properly perform the tuning adjustments.1) IFR A-7550 Spectrum Analyzer / Tracking Gen-erator combination.2) Eagle Model RLB150BN3 Return Loss Bridge(35 dB directivity).3) Double shielded coaxial cable test leads(RG142 B\U or RG223/U).4) 50 Ohm load with at least -35 dB return loss(1.10:1 VSWR).5) Insulated metal blade tuning tool for adjustingceramic and/or piston variable capacitors.Similar equipment from other manufacturersshould yield acceptable results.TUNING PROCEDUREThe following general procedure assumes familiar-ity with the use of a tracking generator.1) Set the tracking generator to a center frequencyof the filter to be tuned. Set the tracking genera-tor for 0 dBm output and a 10 dB/div scale.Connect the equipment as shown in Figure 15but leave the load port of the bridge uncon-nected.2) Set a 0 dB return loss reference. For the IFR A-7550 perform the following procedure:a) Make sure that the unit is in "LIVE" modewhen performing step 7.b) From the Mode Menu, "STORE" the abovetrace.c) Switch to the Display Menu and select"REF". The trace should appear at the 0 dBlevel.3) Connect the load port of the bridge to the filteras shown in figure 15.4) Adjust the cavity main tuning rod for maximumreturn loss at the center frequency.5) Set the tracking generator for the center fre-quency of the filter and connect the test leadsas shown in Figure 16 but first temporarily con-nect the leads together through a female barrelconnector and set a zero dB loss reference. Onthe IFR A-7550 proceed as follows:a) Make sure that the unit is in "LIVE" mode whenperforming step 2.LOADREFLECTEDSOURCEAnalyzerInputGenerateOutput+30+40+20+100-10-20-30-40RLB - 150 Bridge2" Square VHFPseudo-Bandpass FilterTracking GeneratorTuneFigure 15: Tuning the Pseudo-bandpass filter for maximum return loss.
61-38-05 UserMan page 26 of 38TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 26b) From the Mode Menu, "STORE" the abovetrace.c) Switch to the Display Menu and select "REF".6) Connect the leads to the cavity as shown in fig-ure 16 and use a tuning tool or small screwdriver to engage the notch tuning capacitor androtate it to obtain maximum attenuation at thenotch frequency. 7) Tighten the cavity main tuning locking nuts.The cavity may be put back into the repeater ampli-fier.Notch FiltersThe notch filter passes a relatively wide band offrequencies while rejecting (notches out) a verynarrow band of frequencies. They are used toimprove the skirt selectivity of associated band-pass filters. These cavity filters are two inchsquare, helical type resonators that include a tun-able notching section, refer to Figure 17. These fil-ters are pretuned and require no adjustment unlessthey have been damaged and repaired or tam-pered with in some way. They are passive devicesthat require no maintenance. REQUIRED EQUIPMENTDue to the sensitivity of the adjustments, it isstrongly recommended that the proper equipmentbe used when tuning the individual filters, other-wise the filter should be sent to the factory or anauthorized representative for retuning. The follow-ing equipment or it's equivalent is recommended inorder to properly perform the tuning adjustments.1) IFR A-7550 Spectrum Analyzer / Tracking Gen-erator combination.2) Eagle Model RLB150BN3 Return Loss Bridge(35 dB directivity).3) Double shielded coaxial cable test leads(RG142 B\U or RG223/U).AnalyzerInputGenerateOutput+30+40+20+100-10-20-30-402" Square VHFPseudo-Bandpass FilterTracking GeneratorTuneFigure 16: Tuning the Pseudo-bandpass filter for maximum attenuation.Sliding MainTuning Rod(Notch)Main TuningLock NutPassbandTuningCapacitorInput/OutputConnectorsFigure 17: The Notch filter.
TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 2761-38-05 UserMan page 27 of 384) 50 Ohm load with at least -35 dB return loss(1.10:1 VSWR).5) Insulated metal blade tuning tool for adjustingceramic and/or piston variable capacitors.Similar equipment from other manufacturersshould yield acceptable results.TUNING PROCEDUREThe following general procedure assumes familiar-ity with the use of a tracking generator.1) Set the tracking generator to a center frequencyof the filter to be tuned. Set the tracking genera-tor for 0 dBm output and a 10 dB/div scale.Connect the equipment as shown in Figure 18but leave the load port of the bridge uncon-nected.2) Set a 0 dB return loss reference. For the IFR A-7550 perform the following procedure:a) Make sure that the unit is in "LIVE" modewhen performing step 7.b) From the Mode Menu, "STORE" the abovetrace.c) Switch to the Display Menu and select"REF". The trace should appear at the 0 dBlevel.3) Connect the load port of the bridge to the filteras shown in figure 18.4) Adjust the cavity main tuning rod for maximumattenuation at the notch frequency.5) Set the tracking generator for the center fre-quency of the filter and connect the test leadsas shown in Figure 19 but first temporarily con-nect the leads together through a female barrelconnector and set a zero dB loss reference. Onthe IFR A-7550 proceed as follows:a) Make sure that the unit is in "LIVE" mode whenperforming step 2.b) From the Mode Menu, "STORE" the abovetrace.c) Switch to the Display Menu and select "REF".6) Connect the leads to the cavity as shown in fig-ure 19 and use a tuning tool or small screwdriver to engage the notch tuning capacitor androtate it to obtain maximum return loss at thecenter frequency. 7) Tighten the cavity main tuning locking nuts.The cavity may be put back into the repeater ampli-fier.LOADREFLECTEDSOURCEAnalyzerInputGenerateOutput+30+40+20+100-10-20-30-40RLB - 150 Bridge2" Square VHFNotch FilterTracking GeneratorTuneFigure 18: Tuning the Notch filter for maximumreturn loss.
61-38-05 UserMan page 28 of 38TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 28Single Section Amplifier SubassembliesAmplifiers with 400 Milliwatt RF power output rat-ings are manufactured by TX RX Systems, Inc. foruse in the model 61-38-05 family of signal boost-ers. These amplifiers utilize bi-polar transistorsoperating as class-A linear amplifiers with varyingRF power output capability. They offer a good com-promise between low noise figure and low levels ofintermodulation distortion. In addition, these ampli-fiers use narrow band impedance matching cir-cuitry which offers significant improvements innoise figure compared to broadband designs. How-ever, narrow band circuits necessitate having totune the matching networks to obtain best perfor-mance. This tuning procedure needs to be donewhen the RF transistor and/or matching networkcomponents are replaced.Each single amplifier section (see Figure 20) usesa bias regulator circuit to keep the RF transistorbiased for constant collector current with changesin temperature. The collector current remains con-stant when these amplifiers are running properly.The actual value of bias current will be different fordifferent types of amplifiers but can also varyslightly if the power supply voltage varies. All ver-sions of the current production bias regulators aredesigned for fixed values of RF transistor collectorcurrent.The multi section amplifier assembly 3-11423 is acombination of individual single section subassem-blies (part # 3-8089) which have a 400 Milliwattoutput power rating per section. These single sec-tion subassemblies are interconnected with shortlengths of double shielded coaxial cable for the RFinterconnection. The individual sections aremounted on a common bracket with a DC distribu-tion wire running internally between sections. Amulti section amplifier is tuned on a per sectionbasis. Never attempt to tune the interconnectedsections.AMPLIFIER TUNINGField repair and tuning of our amplifiers is sup-ported by TX RX Systems Inc. and the followingprocedure will allow satisfactory operation to beobtained. At the factory, TX RX amplifiers are tunedusing two channel network analyzers that allowadjustment of both gain, input/output return lossand verification of reverse isolation. After this tun-ing, the amplifiers are checked with an advancednoise figure measurement system and are finetuned to obtain best noise figure. Because thisequipment is rarely available in even the most wellequipped service centers, we recommend return-ing the amplifier to the factory for repair and retun-ing if the specified noise figure has to be obtained.In actual practice, most of the amplifiers retuned inthe field will exhibit noise figures that range frombeing equal to the published specification orexceed it by 0.5 to 2 dB. Low noise figure may be ofminimal importance in any system where veryweak signal sensitivity is not an issue.REQUIRED EQUIPMENTThe following procedure was developed to be prac-tical as a field bench service procedure. This pro-cedure is intended for single sections only. All multisection TX RX amplifiers are composed of cas-caded single sections interconnected with shortlengths of double shielded coaxial cable. Individu-ally tuned single sections do not require any furtheradjustment when they are connected togetherAnalyzerInputGenerateOutput+30+40+20+100-10-20-30-402" Square VHFNotch FilterTracking GeneratorTuneFigure 19: Tuning the Notch filter for max attenuation.
TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 2961-38-05 UserMan page 29 of 38forming a multi-section subassembly. This proce-dure requires the following equipment:1) IFR A-7550 Spectrum Analyzer / Tracking Gen-erator combination.2) Eagle RLB150N3 Return Loss Bridge or equiv-alent (35 dB directivity).3) Double shielded coaxial cable test leads(RG142 B\U or RG223/U).4) 50 Ohm load with at least -35 dB return loss(1.10:1 VSWR). JFW Industries model 50T-007or equivalent.5) Regulated DC power supply at the requiredvoltage.6) Insulated metal blade tuning tool for adjustingceramic and/or piston variable capacitors.Similar equipment from other manufacturersshould yield acceptable results.ADJUSTMENT PROCEDURE1) Set the tracking generator output level to -20dBm, the desired center frequency and sweepwidth of 20 MHz.2) Connect the test lead together through a femalebarrel connector to obtain a zero dB referencelevel. On the IFR A-7550 proceed as follows:a) Make sure that the unit is in "LIVE" modewhen performing step 2.b) From the Mode Menu, "STORE" the abovetrace.c) Switch to the Display Menu and select "REF".A display with a vertically centered trace shouldbe visible.3) Connect the equipment as shown in Figure 21.4) Remove the amplifier top cover. Engage theOutput Tuning Capacitors one at a time androtate them for maximum gain. Figure 20: Mechanical layout of a single section amplifier subassembly.Bias RegulatorCircuit BoardOutput TuningCapacitorsRF BoardInput TuningCapacitors
61-38-05 UserMan page 30 of 38TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 305) Engage the Input Tuning Capacitors one at atime and rotate them for maximum gain.NOTE: If the gain peaks at a levelabout 60% of maximum, one of thevariable capacitors should be rotated180° and steps 4 and 5 repeated.6)Connect the return loss bridge tothe tracking generator as shown inFigure 22 but do not connect it to theamplifier. Leave the test port on thebridge open.7) Set up the 0 dB return loss reference. For the IFR A-7550 do the following procedure:a) Make sure that the unit is in "LIVE" mode when performing step 7.b) From the Mode Menu, "STORE" the above trace.c) Switch to the Display Menu and select "REF". The trace should appear at the 0 dB level.8) Connect the bridge and load to the amplifier asshown in figure 22 and see if the input returnloss is down -16 dB or more. If it is, skip to step10.9) Alternately adjust the input tuning capacitors forincreased return loss. A return loss of -20 to -30dB loss should be obtained with maximum lossat the center frequency.10) Reverse the connections as shown inFigure 23 and see if the output return loss is -16 dB or more. If it is, skip to step 12.11) Alternately adjust the output tuning capacitorsfor increased return loss. It should be possibleto obtain -20 to -30 dB loss with maximum lossat the center frequency.NOTEGENERATEOUTPUTANALYZERINPUT+40+30+20+100-10-20-30-40BRIDGEDCAMPLIFIERINPUTOUTPUT50 OHMLOADFigure 22: Measuring input return loss.GENERATEOUTPUTANALYZERINPUT+40+30+20+100-10-20-30-40DCAMPLIFIERINPUTOUTPUTFigure 21: Measuring amplifier gain.
TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 3161-38-05 UserMan page 31 of 3812) Due to interaction, tuning the output circuitryaffects the input tuning and vise-versa. Repeatsteps 8 through 11 until acceptable input andoutput return loss occurs without further tun-ing. 13) Connect the equipment as shown in Figure 24but connect the test leads together through afemale barrel connector and repeat the zeroreference procedure of step 2.14) Using the figure 24 connection, verify that thereverse isolation is at least -20 to -22 dB. Thisvalue will occur normally as the result of propertuning.The greater the reverse isolation the better as thisvalue must exceed the gain of the amplifier or oscil-lation may occur. If after proper tuning this valueremains low, it may indicate a bad bypass capacitoror defective RF transistor.Output Level Control (OLC)The OLC circuits are preset at the factory to limitthe RF power output of the signal booster branch tothe maximum two-carrier level as indicated on thespecification drawing. DO NOT attempt to adjustor change this setting. This setting will be ade-quate for protecting the final amplifier stage andlimiting intermodulation products.OLC voltage data sheets are included with theequipment shipment and list the actual OLC volt-age values in relation to the degree of overloaddetected for your unit. These sheets also recordthe measured 1 dB compression point for thebranch and the calculated output intercept pointbased on this compression point data.CHECKING FOR OVERLOADMeasurement of the DC voltage developed by theOLC circuitry is a way to determine the degree ofinput signal overload. In normal operation, up to 10dB of overload on an intermittent basis is consid-ered acceptable in most installations. Higher levelsGENERATEOUTPUTANALYZERINPUT+40+30+20+100-10-20-30-40DCAMPLIFIERINPUTOUTPUTFigure 24: Measuring reverse isolation.GENERATEOUTPUTANALYZERINPUT+40+30+20+100-10-20-30-40DC50 OHMLOADBRIDGEAMPLIFIERINPUTOUTPUTFigure 23: Measuring output return loss.
61-38-05 UserMan page 32 of 38TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 32generally cause noticeable gain reductions to otherchannels on the system and may also exceed themaximum input level.Connect the positive lead of a multimeter set tomeasure DC voltage on a 0-20 volt scale, to theOLC voltage test point on the OLC assembly. Fig-ure 8 shows the location of the test point on the 3-6280 OLC assembly. The negative lead of the mul-timeter is connected to the chassis. (The black testprobe jacks on the voltage regulator assembly areconvenient for this). Compare the measured volt-age readings with those on the OLC test datasheet to see what degree of overload, if any, is tak-ing place. Refer to the section in this manual titled"Gain Reduction Methods" to correct an excessiveoverload condition.MAINTENANCE AND REPAIRSignal boosters manufactured by TX RX Systems,Inc. can function reliably for 10 or more years withlittle or no maintenance. However, if the amplifiersare subjected to excessively high signal levels,power surges or lightning strikes, failures mayoccur. The following procedures may be followedfor detecting a malfunctioning unit or as part of aperiodic maintenance program.1) Heat sinks for the power amplifiers should becleared of dust and debris.2) Inspect the units to see that the LED DC indica-tors are lit (remove any dust or debris that mayobscure the LEDs). This will verify that DCpower is flowing properly. Check all hardwarefor tightness.3) Compare system performance to initial perfor-mance levels measured when the system wasfirst installed. The lack of signal can be traced toa malfunctioning amplifier by progressive signalmonitoring from the output (far end) to the inputend of the system noting the area where thesignal returns to normal level. The next amplifiertoward the output end of the system will proba-bly be the one that failed.orMeasure the gain of each branch at any conve-nient frequency in the working frequency bandsto verify that the gain specifications are beingmet. If the gain values fall below that specifiedfor a given model check the following:A) Open the signal booster cabinet and inspect forany loose or broken connections or cables, andrepair as necessary.B) Measure the output of the power supply andpower regulators to see that the proper operat-ing voltage is being maintained.C) If the operating voltage is proper but the gain isstill low, measure the gain of each amplifierstage until the one with low gain is isolated.Replace a low gain amplifier with a new ampli-fier stage to correct the problem.RECOMMENDED REPLACEMENT PARTSOne each of the following: Power Amplifier Assem-bly 3-11792, 1stg/3stg Amplifier Assembly 3-11423, Voltage Regulator Assembly 3-5969, andPower Supply Assembly 3-15503.CONVERSION CHARTA Power in Watts to dBm conversion chart isincluded on the following three pages. Most of thesetup and conversion procedures refer to powerlevels in dBm more often than in Watts. This ismuch more convenient when dealing with thepower levels and gain figures of signal boosters.The chart allows easy conversion between the twoscales when necessary.
TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 3361-38-05 UserMan page 33 of 3861-38-05 Signal Booster Family Specifications by Part Number------------------------------------------------------------------- Part Numbers -------------------------------------------------------------------Specification 61-38-05331 61-38-05251 61-38-04401 61-38-04359Frequency Range (MHz) 138 - 144 148 -174 148-174 138 - 144 Minimum Guard Band (MHz) 5.85 9 3.04 4.02Number of Passbands 2222Pass Bandwidth 150 KHz 1 MHz 1.) 1.965 MHz Single Channel 2.) Single Channel 1.56 MHzMaximum Gain (dB) 88 88 88 88Maximum Input Signal Level (dBm) -20 -20 -20 -20Maximum Output Power (1 carrier)Watts +28 +28 +26 +27Gain Set Method--fixed-pads (dB) -3 , -6, -10 -3 , -6, -10 -3 , -6, -10 -3 , -6, -10Gain Adjust Range (dB) 0, -3, -6, -9, -10, -13, -16, -19 0, -3, -6, -9, -10, -13, -16, -19 0, -3, -6, -9, -10, -13, -16, -19 0, -3, -6, -9, -10, -13, -16, -191 dB Compression Point (dBm) 31 31 31 313rd Order Output IP (dBm) 39 39 39 39Output RF Sampler (dB) -50 -50 -50 -50System Noise Figure (dB) without pads 6.5 6.5 6.5 6.5Operating Temperature Range (°C) -30 to +60 -30 to +60 -30 to +60 -30 to +60Nominal Impedance (ohms) 50 50 50 50VSWR 2.0 : 1 2.0 : 1 2.0 : 1 2.0 : 1Input / Output Connectors Type 'N' female Type 'N' female Type 'N' female Type 'N' femaleRF Sampler Port Connectors BNC female BNC female BNC female BNC femaleAC Input Voltage (VAC) 100-120 / 200-240 @ 50/60 Hz 100-120 / 200-240 @ 50/60 Hz 100-120 / 200-240 @ 50/60 Hz 100-120 / 200-240 @ 50/60 HzDC Backup Input Voltage (VDC) 24 - 29 VDC 24 - 29 VDC 24 - 29 VDC 24 - 29 VDCUnit Current Drain 2 Amps DC, <0.5 Amps AC 2 Amps DC, <0.5 Amps AC 2 Amps DC, <0.5 Amps AC 2 Amps DC, <0.5 Amps ACHousing G1: Painted Steel to NEMA 4 G1: Painted Steel to NEMA 4 G1: Painted Steel to NEMA 4 G1: Painted Steel to NEMA 4G2: Stainless Steel to NEMA 4X G2: Stainless Steel to NEMA 4X G2: Stainless Steel to NEMA 4X G2: Stainless Steel to NEMA 4XNominal Size (in./ mm) 24 x 20 x 10 (610 x 508 x 254) 24 x 20 x 10 (610 x 508 x 254) 14 x 19 x 23 (356 x 483 x 585) 36 x 30 x 12 (915 x 762 x 305)Net Weight (Lbs / Kg) 70 (31) 70 (31) 50 (23) 220 (96)
61-38-05 UserMan page 34 of 38TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 3461-38-05 Signal Booster Family Specifications by Part Number---------------------------------------------- Part Numbers ----------------------------------------------Specification 61-38-03324 61-38-04742 61-38-04744Frequency Range (MHz) 138 - 144 138 - 144 138 - 144 Minimum Guard Band (MHz) 4.21 3 2.805Number of Passbands 222Pass Bandwidth 500 KHz/1.0 MHz 1.0 MHz Max 1.185 MHz1.0 MHz 900 KHz/150 KHzMaximum Gain (dB) 88 88 88Maximum Input Signal Level (dBm) -20 -20 -20Maximum Output Power (1 carrier) Watts +26 +26 +26Gain Set Method--fixed-pads (dB) -3 , -6, -10 -3 , -6, -10 -3 , -6, -10Gain Adjust Range (dB) 0, -3, -6, -9, -10, -13, -16, -19 0, -3, -6, -9, -10, -13, -16, -19 0, -3, -6, -9, -10, -13, -16, -191 dB Compression Point (dBm) 31 31 313rd Order Output IP (dBm) 39 39 39Output RF Sampler (dB) -50 -50 -50System Noise Figure (dB) (without pads) 6.5 6.5 6.5Operating Temperature Range (°C) -30 to +60 -30 to +60 -30 to +60Nominal Impedance (ohms) 50 50 50VSWR 2.0 : 1 2.0 : 1 2.0 : 1Input / Output Connectors Type 'N' female Type 'N' female Type 'N' femaleRF Sampler Port Connectors BNC female BNC female BNC femaleAC Input Voltage (VAC) 100-120 / 200-240 @ 50/60 Hz 100-120 / 200-240 @ 50/60 Hz 100-120 / 200-240 @ 50/60 HzDC Backup Input Voltage (VDC) 24 - 29 VDC 24 - 29 VDC 24 - 29 VDCUnit Current Drain 2 Amps DC, <0.5 Amps AC 2 Amps DC, <0.5 Amps AC 2 Amps DC, <0.5 Amps ACHousing G1: Painted Steel to NEMA 4 G1: Painted Steel to NEMA 4 G1: Painted Steel to NEMA 4G2: Stainless Steel to NEMA 4X G2: Stainless Steel to NEMA 4X G2: Stainless Steel to NEMA 4XNominal Size (in./ mm) 30 x 20 x 8 (762 x 508 x 203) 30 x 20 x 8 (762 x 508 x 203) 30 x 20 x 8 (762 x 508 x 203)Net Weight (Lbs / Kg) 75 (33) 75 (33) 75 (33)
TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 3561-38-05 UserMan page 35 of 38dBm dBw Watts Volts (50Ω)80 50 100000 2236.0779 49 79432.82 1992.978 48 63095.74 1776.1777 47 50118.72 1583.0176 46 39810.72 1410.8675 45 31622.78 1257.4374 44 25118.86 1120.6973 43 19952. 62 998.8172 42 15848.93 890.1971 41 12589.25 793.3970 40 10000 707.1169 39 7943.28 630.2168 38 6309.57 561.6767 37 5011.87 500.5966 36 3981.07 446.1565 35 3162.28 397.6464 34 2511.89 354.3963 33 1995.26 315.8562 32 1584.89 281.561 31 1258.93 250.8960 30 1000 223.6159 29 794.33 199.2958 28 630.96 177.6257 27 501.19 158.356 26 398.11 141.0955 25 316.23 125.7454 24 251.19 112.0753 23 199.53 99.8852 22 158.49 89.0251 21 125.89 79.3450 20 100 70.7149 19 79.43 63.0248 18 63.1 56.1747 17 50.12 50.0646 16 39.81 44.6245 15 31.62 39.7644 14 25.12 35.4443 13 19.95 31.5942 12 15.85 28.1541 11 12.59 25.09dBm dBw Watts Volts (50Ω)40 10 10 22.3639 9 7.94 19.9338 8 6.31 17.7637 7 5.01 15.8336 6 3.98 14.1135 5 3.16 12.5734 4 2.51 11.2133 3 2 9.9932 2 1.59 8.931 1 1.26 7.9330 0 1 7.0729 -1 0.79 6.328 -2 0.63 5.6227 -3 0.5 5.0126 -4 0.4 4.4625 -5 0.32 3.9824 -6 0.25 3.5423 -7 0.2 3.1622 -8 0.16 2.8221 -9 0.13 2.5120 -10 0.1 2.2419 -11 0.08 1.9918 -12 0.06 1.7817 -13 0.05 1.5816 -14 0.04 1.4115 -15 0.03 1.2614 -16 0.03 1.1213 -17 0.02 112 -18 0.02 0.8911 -19 0.01 0.7910 -20 0.01 0.719 -21 0.01 0.638 -22 0.01 0.567 -23 0.01 0.56-2400.455-250 0.44-2600.353-2700.322-2800.281-2900.25Power Conversion ChartdBm to dBw: Watts: Microvolts
61-38-05 UserMan page 36 of 38TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 36dBm dBw Watts uVolts (50Ω)0 -30 1.0000E-03 223606.8-1 -31 7.9433E-04 199289.77-2 -32 6.3096E-04 177617.19-3 -33 5.0119E-04 158301.49-4 -34 3.9811E-04 141086.35-5 -35 3.1623E-04 125743.34-6 -36 2.5119E-04 112068.87-7 -37 1.9953E-04 99881.49-8 -38 1.5849E-04 89019.47-9 -39 1.2589E-04 79338.69-10 -40 1.0000E-04 70710.68-11 -41 7.9433E-05 63020.96-12 -42 6.3096E-05 56167.49-13 -43 5.0119E-05 50059.33-14 -44 3.9811E-05 44615.42-15 -45 3.1623E-05 39763.54-16 -46 2.5119E-05 35439.29-17 -47 1.9953E-05 31585.3-18 -48 1.5849E-05 28150.43-19 -49 1.2589E-05 25089.1-20 -50 1.0000E-05 22360.68-21 -51 7.9433E-06 19928.98-22 -52 6.3096E-06 17761.72-23 -53 5.0119E-06 15830.15-24 -54 3.9811E-06 14108.64-25 -55 3.1623E-06 12574.33-26 -56 2.5119E-06 11206.89-27 -57 1.9953E-06 9988.15-28 -58 1.5849E-06 8901.95-29 -59 1.2589E-06 7933.87-30 -60 1.0000E-06 7071.07-31 -61 7.9433E-07 6302.1-32 -62 6.3096E-07 5616.75-33 -63 5.0119E-07 5005.93-34 -64 3.9811E-07 4461.54-35 -65 3.1623E-07 3976.35-36 -66 2.5119E-07 3543.93-37 -67 1.9953E-07 3158.53-38 -68 1.5849E-07 2815.04-39 -69 1.2589E-07 2508.91dBm dBw Watts uVolts (50Ω)-40 -70 1.0000E-07 2236.07-41 -71 7.9433E-08 1992.9-42 -72 6.3096E-08 1776.17-43 -73 5.0119E-08 1583.02-44 -74 3.9811E-08 1410.86-45 -75 3.1623E-08 1257.43-46 -76 2.5119E-08 1120.69-47 -77 1.9953E-08 998.82-48 -78 1.5849E-08 890.2-49 -79 1.2589E-08 793.39-50 -80 1.0000E-08 707.11-51 -81 7.9433E-09 630.21-52 -82 6.3096E-09 561.68-53 -83 5.0119E-09 500.59-54 -84 3.9811E-09 446.15-55 -85 3.1623E-09 397.64-56 -86 2.5119E-09 354.39-57 -87 1.9953E-09 315.85-58 -88 1.5849E-09 281.5-59 -89 1.2589E-09 250.89-60 -90 1.0000E-09 223.61-61 -91 7.9433E-10 199.29-62 -92 6.3096E-10 177.62-63 -93 5.0119E-10 158.3-64 -94 3.9811E-10 141.09-65 -95 3.1623E-10 125.74-66 -96 2.5119E-10 112.07-67 -97 1.9953E-10 99.88-68 -98 1.5849E-10 89.02-69 -99 1.2589E-10 79.34-70 -100 1.0000E-10 70.71-71 -101 7.9433E-11 63.02-72 -102 6.3096E-11 56.17-73 -103 5.0119E-11 50.06-74 -104 3.9811E-11 44.62-75 -105 3.1623E-11 39.76-76 -106 2.5119E-11 35.44-77 -107 1.9953E-11 31.59-78 -108 1.5849E-11 28.15-79 -109 1.2589E-11 25.09Power Conversion ChartdBm to dBw: Watts: Microvolts
TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 3761-38-05 UserMan page 37 of 38dBm dBw Watts uVolts (50Ω)-80 -110 1.0000E-11 22.36-81 -111 7.9433E-12 19.93-82 -112 6.3096E-12 17.76-83 -113 5.0119E-12 15.83-84 -114 3.9811E-12 14.11-85 -115 3.1623E-12 12.57-86 -116 2.5119E-12 11.21-87 -117 1.9953E-12 9.99-88 -118 1.5849E-12 8.9-89 -119 1.2589E-12 7.93-90 -120 1.0000E-12 7.07-91 -121 7.9433E-13 6.3-92 -122 6.3096E-13 5.62-93 -123 5.0119E-13 5.01-94 -124 3.9811E-13 4.46-95 -125 3.1623E-13 3.98-96 -126 2.5119E-13 3.54-97 -127 1.9953E-13 3.16-98 -128 1.5849E-13 2.82-99 -129 1.2589E-13 2.51-100 -130 1.0000E-13 2.24-101 -131 7.9433E-14 1.99-102 -132 6.3096E-14 1.78-103 -133 5.0119E-14 1.58-104 -134 3.9811E-14 1.41-105 -135 3.1623E-14 1.26-106 -136 2.5119E-14 1.12-107 -137 1.9953E-14 1-108 -138 1.5849E-14 0.89-109 -139 1.2589E-14 0.79-110 -140 1.0000E-14 0.71-111 -141 7.9433E-15 0.63-112 -142 6.3096E-15 0.56-113 -143 5.0119E-15 0.5-114 -144 3.9811E-15 0.45-115 -145 3.1623E-15 0.4-116 -146 2.5119E-15 0.35-117 -147 1.9953E-15 0.32-118 -148 1.5849E-15 0.28-119 -149 1.2589E-15 0.25dBm dBw Watts uVolts (50Ω)-120 -150 1.0000E-15 0.22-121 -151 7.9433E-16 0.2-122 -152 6.3096E-16 0.18-123 -153 5.0119E-16 0.16-124 -154 3.9811E-16 0.14-125 -155 3.1623E-16 0.13-126 -156 2.5119E-16 0.11-127 -157 1.9953E-16 0.1-128 -158 1.5849E-16 0.09-129 -159 1.2589E-16 0.08-130 -160 1.0000E-16 0.07-131 -161 7.9433E-17 0.06-132 -162 6.3096E-17 0.06-133 -163 5.0119E-17 0.05-134 -164 3.9811E-17 0.05-135 -165 3.1623E-17 0.04-136 -166 2.5119E-17 0.04-137 -167 1.9953E-17 0.03-138 -168 1.5849E-17 0.03-139 -169 1.2589E-17 0.03-140 -170 1.0000E-17 0.02-141 -171 7.9433E-18 0.02-142 -172 6.3096E-18 0.02-143 -173 5.0119E-18 0.02-144 -174 3.9811E-18 0.01-145 -175 3.1623E-18 0.01-146 -176 2.5119E-18 0.01-147 -177 1.9953E-18 0.01-148 -178 1.5849E-18 0.01-149 -179 1.2589E-18 0.01-150 -180 1.0000E-18 0.01Power Conversion ChartdBm to dBw: Watts: Microvolts
61-38-05 UserMan page 38 of 38TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 38NOTES

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