Foxhunt Antenna Build Night
A successful evening of fun and learning was had, and no holes burned in tables or fingers! Four more Fox Hunt antennas were built tonight, and we still have plenty of parts ‘n pieces for more. I know there were a few out there that stayed back for the weather. Drive home at 8:30pm was starting to get slippery with about 3/4″ of very wet snow on roads. Here’s the ppt presentation for tonight in pdf form. Since it was lab night, it was very informal, so some key information on some slides is verbal and not visual. It’s amazing how simple these beams are to get to tune, only a simple “hair pin” match is used (5″ of wire shorts the coax at the driven element feed point). All four plus the one built last month were well with specs, less than 1.5:1 SWR across the 2M band.
The award for best performing antenna (per the analyzer) goes to Devon (KC1SDD)and Kirby (KC1RWR). Here’s the plot on my analyzer , where the top of the screen is 1.58:1SWR for reference. On the W1WQM repeater input (144.550 MHz) it was very close to 1:1. The marker (dotted vertical line to the right of the ‘Vee’) at the time of the photo was taken, shows the SWR near 146.520 (2M simplex freq) at 1.16:1! That particular beam had a rather long 10′ piece of RG-174 coax (.11″ / 2.79mm diameter) which is little lossy at VHF. Specs state RG-174 to have ~0.116dB loss per foot. But is nice, flexible cable to pass though window or door gaskets in a vehicle while hunting the fox! All other antennas built tonight were using larger RG-58, which has about ~0.071dB loss per foot.
Kriss, KA1GJU