[Lowfer] lowfer transmit antenna

[James Fisher]

I have been experimenting with magnetic loop antennas and am now operating
portable on 160 meters. I note that a 250' long conductor in a magloop will
radiate a signal on the 600 meter band with a efficiency of 25% so 4 watts
into the antenna gets you 1 watt eirp. My magnetic loop is made with 2 inch
wide strips of aluminum flashing. The strips are pop rivited together using
20 rivets at each join and the heads and bases of each rivet are soldered
to the aluminum using harbor freight aluminum solder. On 160 meters I
recieved a report of s-9 for a qrp contact at 5 watts ssb with a 100' long
strip of aluminum. Please note that this length is MUCH longer than normal
for a mag loop, but it works really well! Pictures are on facebook- san
angelo amateur radio hams. The magloop was in a delta shape for easy
installation. the feed was a gamma match using 20' of wire wrapped around
the conductor and then grounded to the aluminum at 20' from the apex which
was the coax ground. I tried feedloops but had no luck as the swr's were
very high. The gamma match worked the first time.