On a few recent towing expeditions in Eloy, the pilots all complained of interference on 151.925, but since I remained on the ground, I never heard it and more or less dismissed it as operator error, telling said pilots to adjust the squelch on their radios. When I towed up from Eloy on Wednesday my arrogance was repaid with interest. I suspect there is a packet service of some type operating on an adjacent frequency, using a tower on Newman Peak as a repeater. Next time I'm out there, I'll try to isolate the frequency in question and either contact the licensee or the FCC.

In the meantime, before heading out to Eloy next time, please ensure your radios are programmed for all the USHPA frequencies, the call sign for which is WPRY420:
151.505
151.625
151.925
151.955
158.400
In general I like to avoid 151.505 in this part of the state because Lifeline was using it to dispatch its EMS helicopters a few years ago, and I think they still are. Lifeline probably uses squelch codes so they're (mostly) not bothered by our transmissions, but we're stuck hearing all of theirs (unless we start using squelch codes). In any case, until most of our pilots are licensed HAMs, we'll need to experiment with various USHPA frequencies in each area to work out which ones are not cluttered with interference.

Now I will repeat my request to those of you who have not yet done so: please get your HAM license. The HAM frequencies allocated for simplex voice communications are generally free of interference and traffic. In the rare case we find actual HAMs chatting on a frequency we're using during flight, they are always curious about what we're doing, happy to move to another frequency to stay out of our way, and in some cases they've offered to provide retrieve.
You need only a Technician license (the lowest level) to do what most pilots want to do, talk on the 2M HAM band (frequencies in the range of 144-148 MHz). You can even use APRS with only a Technician license.
Unlike the old days, a Technician license no longer requires Morse code skills. You need only pass a simple test.
Plenty of resources are available to help you prepare for the test including:
http://www.arrl.org/
http://qrz.com/hamtest/
http://www.hamradiolicenseexam.com/
I imagine that a web search will turn up many more. There are also books on the topic:
http://www.amazon.com/ARRL-Ham-Radio-Li ... io+license
http://www.amazon.com/ARRL-Inc-Tech-lic ... th+edition
When you're ready to take the test, connect with your local HAM club to determine the location and time of the next exam session.
http://www.azqsoparty.org/azclubs.html
http://www.arrl.org/find-a-club
If you have questions or need help, please post here or contact me.