On a chilly February day, FARA members conducted another fun Fox Hunt. The exercise took place the afternoon of February 29th, 2020. This time the Fox Den was led by Bob, KN4SPL along with Garth, K4BOX, and Mike, KF4TEK making up the rest of this iteration of the Fox Den.
The hunters gathered in a parking lot of Liberty High School in Bealeton, VA; no one knew where the trail would take them from there. As the clock struck noon the hunters were off. Using various antennas, radios and other devices to assist, they began their searches for the fox. The Fox was transmitting a strong signal and the hunters easily picked up its telltale CW signal. But this time it transmitted for only 20 seconds every minute, making it a dastardly one indeed.
The signal led the hunters to a parking area behind the Moo Thru in Remington, and into the SFSSC Disc Golf Course. After wending around the trails of the course, most of the hunters arrived together in the same general area – each one pointing antennas and adjusting attenuators frantically during the 20-second transmissions. As John, KX4O, stood in front of a tree next to the trail he was heard to exclaim “Aha!” as he located the well-concealed Fox. Congratulations, John!
The signal led the team behind the Moo-Thru in Remington and over into the SFSSC Disc Golf Course. Eventually the winning hunter was John, KX4O! Congratulations John.
A big thank you to the Fox Den for organizing the event! The other hunters who participated in the fun and learning were: Frank, KO4CAP; Justin, KO4BWC, with his son Colt; Bruce, KN4GDX, Allen, AG4VA; Brad, N7IVV; and Rich, K1HTV. Good job team!
John, KX4O, explains his unique experience with searching for the Fox below the slide show.
From KX4O:
I didn’t really mean to participate, but when I stopped by to check things out, I figured why not see what a mobile set up can do.
Lessons learned from FARA’s Fox Hunt veterans
I listened closely to the lessons learned in the run up to and execution of the previous FARA Fox Hunt. I paid particular attention to the need for attenuation via, well, attenuation, working slightly off frequency, working at the 3rd harmonic or some combination thereof.
Booming signal
Gotta hand it to the Fox transmitter. I heard it mobile for miles in every direction around Bealeton. Quite the signal and let’s give it to 2m for being a good band for moving across the land. I tuned 5 kHz or so off to lesson the sensitivity and that did help shrink the area a bit. The real benefit came when tuning to the 3rd harmonic of the Fox transmitter. Same good signal, but much less of it. I wasn’t really searching in any efficient way… just looking at relative signal strength while driving in all directions. Hardly elegant.
The search shrinks
Finally got a booming 3rd harmonic signal heading south 28 at 28/29 intersection after one last unproductive romp through greater Remington. I knew there was public property suitable for Fox Hunt romping west of 29, but wasn’t really sure what state it was in. There really wasn’t a location better for this event on north or south 29 so straight I went to find the little parking lot near Moo Thru… and there the organizers were.
Thank you Garth
Well when you are only mobile and need to perform the final detection, you need something portable. Garth (I think) lent me his Yagi-Uda, HT and attenuator. It quickly became clear the power of the Fox transmitter was stronger than the attenuator’s capability. I finally was just using the HT with a 6 inch coax and nothing else. Then tuned to the 3rd harmonic. Then when finally near the spot, removed the antenna entirely and used the body block trick to null. This barely worked, but well enough to find the tree to stare at for a ridiculous long time… and then there it was.
I think K3FRG provided much of the tips I used in this effort. Thanks!
Next time a jammer happens upon the repeater, I have new tricks to use. Cool.
