YOU'RE HEARD, LOUD AND CLEAR. Installation and Operation Manual for T-Pass® Transmit Multicouplers 73-67-11 Series and 73-67-25/25 (High Power) Series Manual Part Number 7-9120 8625 Industrial Parkway, Angola, NY 14006 Tel: 716-549-4700 Fax: 716-549-4772 sales@birdrf.com www.bird-technologies.
Warranty This warranty applies for five years from shipping date. TX RX Systems Inc. warrants its products to be free from defect in material and workmanship at the time of shipment. Our obligation under warranty is limited to replacement or repair, at our option, of any such products that shall have been defective at the time of manufacture. TX RX Systems Inc. reserves the right to replace with merchandise of equal performance although not identical in every way to that originally sold. TX RX Systems Inc.
Manual Part Number 7-9120 Copyright © 2010 TX RX Systems, Inc. First Printing: January 1994 Version Number Version Date 1 04/01/94 2 08/02/94 3 03/27/96 4 11/30/06 5 07/26/10 Symbols Commonly Used WARNING ESD Electrostatic Discharge CAUTION or ATTENTION Hot Surface High Voltage Electrical Shock Hazard Heavy Lifting Bird Technologies Group NOTE Important Information TX RX Systems Inc.
Changes to this Manual We have made every effort to ensure this manual is accurate. If you discover any errors, or if you have suggestions for improving this manual, please send your comments to our Angola, New York facility to the attention of the Technical Publications Department. This manual may be periodically updated. When inquiring about updates to this manual refer to the manual part number and revision number on the revision page following the front cover.
Table of Contents General Description ........................................................................................... 1 Unpacking ............................................................................................................ 4 Installation Overview........................................................................................... 5 RF Cables and Connectors ................................................................................. 5 Intermodulation Considerations ....
Figures and Tables Figure 1: Block diagram of typical system ............................................................ 1 Figure 2: Noise suppression graph for 6.625” cavities .......................................... 2 Figure 3: Noise suppression graph for 10” cavities ............................................... 3 Figure 4: Typical Peg rack model .......................................................................... 4 Figure 5: Typical 19” Relay rack model .......................................
GENERAL DESCRIPTION The model 73-67-11/25-XX-NN Series T-Pass Transmit Combiners are designed to connect multiple transmitters to a common antenna. They use three-port bandpass filters (called T-Pass cavities) and ferrite isolators to provide low channel insertion loss, high isolation between transmitters, high antenna-to-transmitter isolation, high intermodulation suppression, and excellent transmitter noise suppression.
Frequency Range (MHz) 406 - 512 MHz Cavity Type and Diameter 3/4 wave, 6.625” (168 mm) Maximum Continuous Transmit Power 150 Watts Isolator Load Power (Continuous) 73-67-11-2B-nn: 5W/25W [Note 3] ; 73-67-11-2D-nn: 5W/100W Minimum TX-TX Separation at Cavity Loss 215 KHz @ -1.5 dB ; 115 KHz @ -2.
Frequency Range (MHz) 406 - 512 MHz Cavity Type and Diameter 3/4-wave, 10” (254 mm) Maximum Continuous Transmit Power 150 Watt Isolator Load Power (Continuous) 5W/25W [Note 3] Minimum TX-TX Separation at Cavity Loss 150 KHz @ -1.5 dB ; 75 KHz @ -2.5 dB Typical TX-TX Isolation at Minimum Separation (dB) 80 dB Typical Antenna - TX Isolation (dB) 70 dB Typical TX Noise Suppression Depends on cavity loss Nominal Impedance (Ohms) 50 Maximum Input Return Loss (VSWR) -20 dB (1.
The number of channels in the combiner is indicated by the last two digits of the model number in place of the NN designation. All of the information for both installation and expansion is included in this manual. The combiner is easy to install and has been factory tuned in most cases so that no adjustments are necessary. The specifications for the 73-67-11/25-XX-NN family of T-Pass combiners are listed in Tables 1 and 2 for the 6.625” and 10” cavities respectively.
The transmit combiner is a very rugged device and is well packed for damage-free shipping to any place in the world. However, a high impact during shipping can have a detrimental affect. A damaged shipping container is a sure sign of rough handling. The most easily damaged parts of the combiner are the tuning rods. These rods are marked where they exit from the locking nut with a dab of red varnish or other color/type of paint.
Both cavity filters and ferrite isolators isolate the transmitters connected to the combiner from oneanother thus reducing intermodulation interference. However in all transmitter combiners, intermodulation products are reduced in strength but never completely eliminated. They have to be reduced by an amount to meet the federal Communications Commission, 43 + 10 Log(Power Out) rule for spurious output reduction.
3) Verify proper operation of each channel by measuring the power output for each individual channel. TRANSMITTER COMBINER CHECKOUT It is recommended that the performance of the transmitter combiner be checked initially and data recorded for future reference. This is done by measuring the input and output power of each channel and recording the data. Figure 7 shows the equipment hook up.
ing action of filters. Since the filters are usually tuned using laboratory grade 50 ohm loads, the tuning adjustment that produces this improved match will be slightly different than the factory adjustment. While this tuning may produce slightly greater power output readings, it will rarely produce any discernible change in system performance and may detune any notching circuitry contained in the cavities.
Coarse Tuning Rod Fine Tuning Rod Coarse Tuning Lock 10-32 Cap Screw Input/Output Port Cavity Resonator Loop Plate Assembly Input/Output Port Calibration Mark Loop Plate Hold Down Screws Calibration Index Loop Plate Assembly Fine Tuning Lock Knurled Thumb Nut Calibration Index Figure 9: T-Pass cavity tuning controls details. 4) Tighten the fine tuning locking mechanism.
Spectrum Analyzer Bird SignalHawk PROCEDURE 1) Set the spectrum analyzer for the desired center frequency (display center) and vertical scale of 10 dB/div. Set the signal generator for the desired center frequency. 2) Connect the return loss bridge to the spectrum analyzer and signal generator as shown in figure 10 but do not connect it to the cavity. Leave the test port (called the load port) on the bridge open. 3) Set up a 0 dB return loss reference display on the spectrum analyzer.
4) Fine tune each channel using the fine tuning procedure starting with channel 1 and proceeding to the next higher channel. After tuning all channels, repeat this step a second time to verify that their is no more channel interaction. (1) Cavity and isolator mounting hardware. 5) Verify channel losses if desired using the checkout procedure outlined previously. PEG RACK PROCEDURE (6.
Figure 11: Peg-rack mounting details. cable sheet. Follow the procedure outlined below under Setting Cavity Insertion Loss. 11) Fine tune the T-Pass cavity of the expansion channel according to the fine tuning procedure outlined earlier. RELAY RACK PROCEDURE (10” CAVITIES) NOTE Because of their width, 10” cavities are mounted in relay racks with a vertical orientation as shown in Figure 12. 1) Install the expansion cavities to the rack above existing channels using four mounting screws.
Screw Screw Screw Screw Figure 12: Relay rack mounting details. Ten-inch cavities shown as an example. 5) Fine tune the T-Pass cavity of the expansion channel according to the fine tuning procedure outlined earlier. 1) Determine the location of the expansion channel in the rack by consulting the new THRULINE cable chart. RELAY RACK PROCEDURE (6.625” CAVITIES) Because of their width, 6.625” cavities are mounted on relay racks in a horiNOTE zontal or ientation on cavity deck plates.
4) Rotate the cavity body so that the connectors are oriented the same as those on the other cavities in the system. Secure the new cavity to the brackets using (2) stainless band clamps. 5) Tighten the cavity mounting band clamps. 6) Connect the black isolator-to-cavity cable using a pair of cable pliers to tighten-up the connectors. 7) Connect the new channel to the combiner using the proper length T-Pass Thruline cable. Use a pair of cable pliers to tighten these connections.
Cavity Loss (dB) Coupling Loop Type TXRX Part # Reference Notch Depth T-Pass 3-3724 -9.2 Bandpass 2-0675 -12 T-Pass 3-3724 -7.4 Bandpass 2-0675 -10.2 T-Pass 3-3724 -5.6 Bandpass 2-0675 -8.8 T-Pass 3-3724 -4.4 Bandpass 2-0675 -8.0 T-Pass 3-3724 -3.6 Bandpass 2-0675 -7.2 1.0 1.5 2.0 2.5 3.0 Table 3: Cavity insertion loss reference loop settings. Cavity Loss Setting Procedure 1 This procedure uses precision rotary attenuators, a signal generator and an RF millivolt meter.
Modulated Signal Source RF Voltmeter 1 All cables are 50 Ohm coaxial. Double shielded cables preferred. 0 00 00 0 00 ZERO SET 2 3 4 56 7 8 9 3 10 ZERO SET 50 Ohm Adaptor UG914/U Female-Female Connector 0.1 dB/Div. 1.0 dB/Div. 10 dB/Div. 10 dB Attenuator Pads Rotary Attenuators Set to Loop Reference Settings Figure 14: Setting loop adjustment reference level. tor pads. UG-201 BNC to N adapters are used when connections to N connectors are needed. shown.
Modulated Signal Source RF Voltmeter UG-28A/U UG-57B/U T-Pass Loop 50 Ohm Adaptor Short Circuit Connector 3-1268 from top of rack 10 dB Pad 10 dB Pad 0.1 dB/Div. 1.0 dB/Div. 10 dB/Div. Rotary Attenuators Set to Loop Reference Settings Bandpass Loop turned upside down with connector inserted into cavity. Loop visible and screws tight. Figure 15: Setting the T-Pass loop using step attenuators. 8) Repeat steps 6 and 7 until the minimum meter reading is equal to the reference level from step 2.
Modulated Signal Source RF Voltmeter UG-28A/U UG-57B/U Bandpass Loop 50 Ohm Adaptor 10 dB Pad 10 dB Pad 0.1 dB/Div. 1.0 dB/Div. 10 dB/Div. Rotary Attenuators Set to Loop Reference Settings Small Circle on Bandpass Loop indicates ground end of loop and should be oriented as shown. Previously calibrated T-Pass Loop 3-1268 short circuit removed. Figure 16: Setting the bandpass loop using step attenuators. the index mark points to a slightly lower number on the calibration index.
Signal Generator UG-28A/U UG-57B/U T-Pass Loop 10 dB Pad 10 dB Pad Short Circuit Connector 3-1268 from top of rack Bandpass Loop turned upside down with connector inserted into cavity. Loop visible and screws tight. Spectrum Analyzer Bird SignalHawk Figure 17: Setting a T-Pass loop for specific cavity insertion loss. 2) Connect the test leads to the spectrum analyzer; turn it on and let it warm up for at least 30 minutes.
slightly less than the reference. The Notch depth will tend to increase slightly as all three locking screws are tightened. 5) If the Reference Notch Depth is 8 dB or less then set the display for a vertical range of 2dB/ div otherwise set it for 10dB/div. 12) Remove the bandpass loop and place it back into the cavity with the connector-end up. 6) Temporarily connect the test leads from the spectrum analyzer together through a UG-914 BNC union to set the zero reference.
necessary to rotate the loop for a notch depth that is slightly less than the reference. The Notch depth will tend to increase slightly as all three locking screws are tightened. 11) Tighten all loop locking screws. The cavity loss is now set. The cavity will have to be tuned to its operating frequency following the procedures outlined earlier in this manual.
Appendix A UHF Isolators (Compact Style) GENERAL DESCRIPTION Isolators perform two important functions. Their primary function is to keep other RF frequencies out of the transmitter so that intermodulation products cannot be generated. Isolators have a substantial amount of reverse isolation. They also insure that the transmitter never sees any significant reflected power so it will always operate with maximum stability at full-power output.
5) Inject a test signal (-10 dBm) from the tracking generator into the output port of the isolator. The test signal should sweep across the operating bandwidth of the isolator. Measuring Insertion Loss (S21) The insertion loss of your isolator can be verified by performing the following procedure in a step-bystep fashion. 6) Compare your displayed waveform against the example shown in Figure A3 as well as the specification listed in table A1.
2) Disconnect the input and output cable to the isolator. 3) Connect a tracking generator and spectrum analyzer to the input and output ports of the isolator respectively, as shown in Figure A2. 4) Make sure that a 50 Ohm load is connected to the load port of the isolator. If you are testing the isolator on the bench make sure you connect a load. If you are testing the isolator while it is still mounted on the system rack/cabinet leave the existing load connected.
TXRX Systems Part # Freq Range (MHz) Isolation (dB) (min) Insertion Loss (dB) (max) TXRX Systems Part # Freq Range (MHz) Isolation (dB) (min) Insertion Loss (dB) (max) 3-8195P 295 - 400 18 0.60 3-20721PL 300 - 350 23 0.22 3-23018P 390 - 420 25 0.25 3-10010PL 350 - 400 23 0.22 3-23269P 380 - 400 25 0.25 3-23425PL 380 - 400 25 0.22 3-8191P 406 - 430 25 0.35 3-8196PL 406 - 430 25 0.22 3-22401P 430 - 450 25 0.35 3-8201PL 430 - 450 25 0.
RX Systems Inc. 8625 TX Industrial Parkway, Angola, NY 14006 7-9120-5 Tel:Manual 716-549-4700 Fax: 716-549-4772 07/26/10 sales@birdrf.com Page 26 www.bird-technologies.
