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Frequency Type -10.7 Type   +10.7 Type
121.5 MHz
Civil Aviation Emergency 110.8 VOR   132.2 Comm
121.6 MHz
Non-CAP ELT Training 110.9 ILS   132.3 Comm
121.775 MHz
CAP Practice Beacons 111.075 none   132.475 Comm
243.0 MHz
Military Emergency/Guard 116.15 VOR   126.85 Comm
243.2 MHz
2nd Harmonic of 121.6 MHz 116.25 VOR   126.95 Comm
243.55 MHz
2nd Harmonic of 121.775 MHz 116.425 none   127.125 Comm
251.9 MHz
Military ELT Training 120.60 Comm   131.3 Comm
282.8 MHz
Military Survivor Voice 136.05 none   146.75 Amateur Radio

For VHF frequencies selected in the L-Tronics LA-Series DF, the unit may interfere with the selected frequency +/- 10.7 MHz (the intermediate frequency). It may interfere with either aircraft communications or navaids according to the chart above.

For UHF frequencies selected in the DF unit, interference on the half harmonic of the selected frequency +/- 10.7 MHz.

Those interfered frequencies listed as "none" could possibly still interfere with a nearby ILS, VOR, or Communications frequency but the chances are far more remote. The interfered frequencies for 282.8 MHz are both outside the aviation navigation and communication bands, but the upper frequency is within the Amateur Radio spectrum.

This list is not all inclusive. If you have additional frequency crystals installed in your DF unit that are not listed here you must calculate the interfered frequencies using the following equations: VHF DF Freq +/- 10.7 UHF (DF Freq +/- 10.7)/2

Interference may possibly occur when using an LH-series L-Per portable DF unit.   Of special note might be conflicts with amateur radio frequencies.

For more information on some of the lesser-known frequencies listed in this table, see the UHF L-Per Training page.


This page of the CAP Emergency Services Resources website was last updated 01/06/2009

1998 - 2006 Scott E. Lanis.  All Rights Reserved.