YOU'RE HEARD, LOUD AND CLEAR. Instruction Manual Vari-Notch® Cavity Filter 4” Diameter Manual Part Number 7-9150 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 7-9150 Copyright © 2007 TX RX Systems, Inc. First Printing: October 1996 Version Number Version Date 1 10/18/96 2 07/19/07 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.
+10 0 -10 Passband -20 -30 -40 Rejection Notch -50 -60 -70 Analyzer Input Generate Output Figure 1: Spectrum Analyzer/Tracking Generator display of the lowpass 4” Vari-Notch filter. Response curve shown for model number 15-52-01 (215-250 MHz) GENERAL DESCRIPTION The 4" Vari-Notch® cavity filter is designed to pass a relatively narrow band of frequencies (passband) while simultaneously rejecting a wide band of frequencies (rejection notch).
Tuning Rod Schematic Symbol 1/4" Shaft Locking Nut Loop Assembly Cavity Resonator Input/Output Ports Variable Capacitor Figure 2: The 4” Vari-Notch filter. Tuning Procedure Tuning of the filter requires adjustment of the passband and the rejection notch. The passband is adjusted while observing the return loss response and the rejection notch is adjusted by monitoring the output of a tracking generator after it passes through the filter.
+40 +40 +30 +30 +20 +20 +10 +10 0 0 -10 -10 -20 -20 -30 -30 -40 -40 Generate Output Analyzer Input REFLECTED RLB - 150 Bridge SOURCE REFLECTED RLB - 150 Bridge Generate Output LOAD Figure 3: Setting the return loss reference. SOURCE Analyzer Input LOAD 4" Diameter Vari-Notch Filter 7. Connect the "load" port on the RLB to one of the input /output ports and make sure the remaining port is connected to a 50 ohm load; refer to Figure 4.
+10 0 -10 -20 -30 -40 -50 -60 -70 Analyzer Input Generate Output Also, the interconnecting cable between the two filters, when cut to the correct length (odd multiple of a 1/4 λ), will provide up to 6 dB of additional attenuation due to a mismatch of impedance between the cable and the filters. The 6 dB of mismatch attenuation does not occur at the filters passband but, only at frequencies where moderate to high attenuation occurs, such as at the rejection notch frequency.
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 TX RX Systems Inc.
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.
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.
