YOU'RE HEARD, LOUD AND CLEAR. Instruction Manual Series-Notch® Cavity Filters 6 5/8” and 10” Diameter Manual Part Number 7-9146 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 7-9146 Copyright © 1996 TX RX Systems, Inc. First Printing: July 1996 Version Number Version Date 1 07/25/96 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.
GENERAL DESCRIPTION The Series-Notch® cavity filter passes a relatively wide band of frequencies (passband) while simultaneously rejecting a very narrow band of frequencies (notch frequency). Minimum separation between passband and notch frequency is 50 KHz. The notch depth is variable from 15 to 25 dB. A variety of models are available that cover the range of frequencies from 30 to 960 MHz. The frequency range that each model will tune across is determined by the cavity's physical length.
dBm 1 MHZ/DIV 300 KHZ/RES 98.00 MHZ 20 dB 1 MHZ/DIV 300 KHZ/RES 98.00 MHZ 40 Passband High Frequency Portion Passband Low Frequency Portion 10 30 0 20 -10 10 Notch Frequency Passband Low Frequency Portion -20 Passband High Frequency Portion 0 -30 -10 Notch Depth Notch Frequency -40 -20 -50 -30 -60 -40 50 dB ATT GEN 0 dBM 10 MSEC 50 dB ATT 10 MSEC GEN 0 dBM Figure 3: Spectrum Analyzer / Tracking Generator display of the Series-Notch filter tuned symmetrically.
TUNING Required Equipment The following equipment or it's equivalent is recommended in order to properly perform the tuning adjustments for the Series-Notch filter. 1. IFR A-7550 Spectrum Analyzer with optional Tracking generator installed. depth is factory set, at which time a relative index label is attached to the top of the cavity next to the loop plate and a calibration mark is stamped into the loop plate itself. The relative index label is used to log specific filter performance.
dB 40 1 98.00 300 MHZ / DIV MHZ KHZ RES 30 20 10 0 -10 -20 -30 -40 50 dB ATT GEN 0 dBM 10 MSEC GENERATE ANALYZER FEMALE UNION Used to set 0 dB reference 0 5 10 15 20 Series-Notch Filter Figure 6: Checking notch depth and notch frequency. (calibrated by factory). Rotating the loop plate assembly and moving the calibration mark above 0 causes the notch depth to be increased. It is adjustable across a useable range of from 15 dB to 25 dB.
range of the filter. The air-plate type has a red mark painted on the access barrel and one-half of the adjusting screw, when the red marks line up the maximum amount of capacitance is achieved. 3. Do not connect the return loss bridge to the cavity, leave the "load" port on the bridge open. This will supply the maximum amount of reflected energy to the analyzer input. A transmitter connected to the filter will operate best when the reflected energy is lowest.
but, only at frequencies where moderate to high attenuation occurs, such as at the notch frequency. Because each of the filters in the multi-cavity arrangement are identical, the passband for the entire arrangement is generally the same as the passband for the individual filters. However, each filters individual insertion loss is also additive. dB 40 1 98.00 300 MHZ / DIV MHZ KHZ RES 30 When tuning a multi-cavity arrangement, each filter is tuned individually prior to interconnecting.
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.
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 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.
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.
