DF In My Living Room
I recently purchased a brand-spankin'-new L-Tronics LH-16 Little L-Per. I felt it was the next reasonable piece of equipment that could help myself be mission ready. When I combine that thought with the fact that my squadron didn't have its own L-Per, well, rather than wait until they could raise $500 I'd just fork it out myself. Not that the tax deduction will help me any since I don't own my own home (grumble grumble).
I was very excited when the package came in the mail . . . Christmas had come early! In additon to the standard items, my new L-Per included 2 special-order crystals: one for 251.9 MHz and another for 243.55 MHz. The first will be used to DF military practice beacons and the second will DF CAP 121.775 MHz practice beacons at short range. See UHF L-PER TRAINING on this site for more information about this subject.
The big surprise came when I turned the unit on inside of my living room. I was receiving a signal on 243.0 MHz! What in the world!?? The signal was obviously not a beacon: it was carrier only. The controlling facilities here on the AF base frequenty transmit on 243.0 for a variety of reasons, but this was not eminating from their broadcast antennas, either. The signal was admittedly very weak: I had the sensitivity nearly maxxed but was sure this wasn't just "static" because I had reliable deflection in the DF mode.
Interested, I DFed the signal. The source ended up being a power strip behind my entertainment center! The signal was so weak that it couldn't even be reliably DFed in the next room. In another room in my house, however, I found that I could DF to my printer on 121.6 MHz.
The moral of the story? Radio frequency (RF) noise comes in all shapes and sizes from all manner of devices. It is often very weak but also can be found from any complex electronic device. Keep this in mind when you're looking for the real ones--at close ranges, two signals can be very difficult to sort out. Maybe try DFing around your house for practice and just to see what radiates. Its geeky but fun! It is well documented that occaisionally these type of RF radiators will activate the SARSAT system--one of the many reasons for the elimination of primary alerting on 121.5 and 243.0 MHz. In any case, good luck and good hunting!
This page of the CAP Emergency Services Resources™ website was last updated 07/01/2008
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