[Antennas] 40m mobile antenna e.r.p. compared

Sat Apr 30 12:55:11 EDT 2005

Sam,

Don't limit yourself to a vertical antenna. You can buy a 12' fishing rod 
(black), discard the top whip section, run two parallel wires either inside or 
outside of the pole, and use #24 wire to form a balanced dipole that would 
attach to the diagonal corners of the roof. The wire will be so fine that it 
won't even be noticed, and you can get about 33' on either side if you run it 
diagonally across the roof. Don't use end insulators, use fine fishing line 
to support the 33' ends. Feed at the base with 300 ohm twinlead and you'll 
have a very effective antenna that you can tune on 40, and all the bands 
above that, including the WARC bands,

This full-sized antenna will outperform any mobile whip you can buy. It may 
even work marginally on 80M. With the wires above the flat roof, you have 
less likelihood of inducing RF currents into the ceiling wiring, which may 
happen with radials.

I used this technique on a flat-roofed apartment in Okinawa, Japan, and 
consistently worked the states on 40M running QRP. Trust me, your limiting both 
bandwidth and performance if you use a mobile antenna of any kind.

Paul, K5AF