YOU'RE HEARD, LOUD AND CLEAR. Instruction Manual Bandpass Cavity Filters 6 5/8” and 10” Diameter Manual Part Number 7-9145 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 one year 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 7-9145 Copyright © 1996 TX RX Systems, Inc. First Printing: August 1996 Version Number Version Date 1 08/05/96 Symbols Commonly Used WARNING ESD Elecrostatic Discharge CAUTION or ATTENTION Hot Surface High Voltage Electrical Shock Hazard Use Safety Glasses Bird Technologies Group NOTE Important Information TX RX Systems Inc.
dBm 1 MHZ/DIV 300 KHZ/RES 98.00 MHZ 10 0 INSERTION LOSS -10 -20 -30 -40 PASS FREQUENCY -50 -60 -70 40 dB ATT 10 MSEC GEN 0 dBM Figure 1: Spectrum Analyzer / Tracking Generator display of the Bandpass filter. Response curve shown for model # 11-29-01 (88 - 108 MHz) GENERAL DESCRIPTION The Bandpass cavity filter passes one narrow band of frequencies (passband) and attenuates all others with increasing attenuation above and below the pass frequency.
Schematic Symbol Cavity Resonator Coarse Tuning Rod Coarse Tuning Lock 10-32 Cap Screw Loop Plate Assembly Calibration Index Input/Output Port Calibration Mark Calibration Mark Input/Output Port Calibration Index Loop Plate Assembly Fine Tuning Rod Fine Tuning Lock Knurled Thumb Nut Loop Plate Hold Down Screws Figure 2: The Bandpass filter. labeled in figure 1. All of the physical components of the filter are labeled in figure 2, with the adjustable parts shown in emboldened italics.
2. The resonant frequency of the filter is checked by connecting the tracking generator to the input of the cavity filter while the spectrum analyzer is connected to the output, as shown in figure 3. dB 8 50 98.00 300 KHZ / DIV MHZ KHZ RES 6 4 2 0 -2 -4 -6 -8 40 dB ATT GEN 0 dBM 10 MSEC adjustment (invar rod) that rapidly tunes the filter's response curve. The resonant frequency is increased by pulling the rod out of the cavity and is decreased by pushing the rod into the cavity.
decreases it). The insertion loss is adjustable across a useable range of from 0.5 dB to 3.0 dB. It is important to set both loops to the same index number so that the cavity's insertion loss remains balanced. cause the stored value to be displayed on the screen as the 0 dB reference value. 4. Connect the generator output and analyzer input to the input/output ports of the loop plates and the insertion loss will be displayed on the IFR A-7550's screen, refer to figure 3. 5.
The filter's loop plate assembly may be changed in order to convert the cavity from one type of filter to another. Conversion kits can be ordered which contain all required parts for the conversion. The available conversion kits are listed by part number in table 2. Refer to the appropriate TX RX Systems Inc. manual for the specific filter type once the kit is installed.
Power Ratio and Voltage Ratio to Decibel Conversion Chart Loss or Gain +9.1 dB -9.1 dB Power Ratio 8.128 0.123 Voltage Ratio 2.851 0.351 - dB + Voltage Ratio 1 0.989 0.977 0.966 0.955 0.944 0.933 0.923 0.912 0.902 0.891 0.881 0.871 0.861 0.851 0.841 0.832 0.822 0.813 0.804 0.794 0.785 0.776 0.767 0.759 0.75 0.741 0.733 0.724 0.716 0.708 0.7 0.692 0.684 0.676 0.668 0.661 0.653 0.646 0.638 0.631 0.624 0.617 0.61 0.603 0.596 0.589 0.582 0.575 0.569 Power Ratio 1 0.977 0.955 0.933 0.912 0.891 0.871 0.851 0.
Bird Technologies Group TX RX Systems Inc.
Bird Technologies Group TX RX Systems Inc.
Bird Technologies Group TX RX Systems Inc.
Isolation Curves for Transmitter/Receiver The curves shown below for use with filters, duplexers, and multicouplers, indicate the amount of isolation or attenuation required between a typical 100 watt transmitter and its associated receiver at the TX (carrier suppression) and RX (noise suppression) frequency which will result in no more than a 1 dB degradation of the 12 dB SINAD sensitivity.
POWER IN/OUT VS INSERTION LOSS The graph below offers a convenient means of determining the insertion loss of filters, duplexers, multicouplers and related products. The graph on the back page will allow you to quickly determine VSWR. It should be remembered that the field accuracy of wattmeter readings is subject to considerable variance due to RF connector VSWR and basic wattmeter accuracy, particularly at low end scale readings.
POWER FWD./REV. VS VSWR 500 400 V S W R 300 200 100 1.1:1 FORWARD POWER (Watts) 50 40 1.15:1 30 1.2:1 20 1.25:1 1.3:1 10 1.4:1 5.0 4.0 1.5:1 3.0 1.6:1 1.8:1 2.0 2.0:1 1.0 2.5:1 3.0:1 0.5 40 20 10 8.0 6.0 4.0 2.0 1.0 0.8 0.6 0.4 0.2 REFLECTED POWER (Watts) FOR OTHER POWER LEVELS MULTIPLY BOTH SCALES BY THE SAME MULTIPLIER Bird Technologies Group TX RX Systems Inc.
Power Conversion Chart dBm to dBw to Watts to Volts dBm dBw Watts Volts 50Ω dBm dBw Watts Volts 50Ω 80 50 100kW 2236 18 -12 63 mW 1.78 75 45 31.6 kW 1257 17 -13 50 mW 1.58 70 40 10.0 kW 707 16 -14 40 mW 1.41 65 35 3.16 kW 398 15 -15 32 mW 1.26 60 30 1000 224 14 -16 25 mW 1.12 55 25 316 126 13 -17 20 mW 1.00 50 20 100 70.7 12 -18 16 mW 0.890 45 15 31.6 39.8 11 -19 13 mW 0.793 40 10 10.0 22.4 10 -20 10 mW 0.707 38 8 6.31 17.
Free Space Path Loss Estimator Path Length (miles) Frequency in MHz 50 150 170 450 500 800 900 0.1 50.58 60.12 61.21 69.66 70.58 74.66 75.68 0.25 58.54 68.08 69.17 77.62 78.54 82.62 83.64 0.5 64.56 74.10 75.19 83.64 84.56 88.64 89.66 1 70.58 80.12 81.21 89.66 90.58 94.66 95.68 2 76.60 86.14 87.23 95.68 96.60 100.68 101.71 3 80.12 89.66 90.75 99.21 100.12 104.20 105.23 4 82.62 92.16 93.25 101.71 102.62 106.70 107.73 5 84.56 94.10 95.19 103.
Return Loss vs. VSWR Watts to dBm Return Loss VSWR Watts dBm 30 1.06 300 54.8 25 1.11 250 54.0 20 1.20 200 53.0 19 1.25 150 51.8 18 1.28 100 50.0 17 1.33 75 48.8 16 1.37 50 47.0 15 1.43 25 44.0 14 1.50 20 43.0 13 1.57 15 41.8 12 1.67 10 40.0 11 1.78 5 37.0 10 1.92 4 36.0 9 2.10 3 34.8 2 33.0 1 30.
8625 Industrial Parkway, Angola, NY 14006 Tel: 716-549-4700 Fax: 716-549-4772 sales@birdrf.com www.bird-technologies.
