[Antennas] SOME INFO PLEASE ON GAP 160 80 40

Fri Nov 26 09:11:26 EST 2004

Several people inquired about my WARC dipoles, so here goes:
They are made entirely from 450 Ohm ladderline. Each half of the flat-top 
has one of the 450 Ohm wires 22' 4" long, with the 2'nd wire cut 12' 10½" 
long, both wires connected together at the feedpoint. The unused wire 
beyond the cut is left in place. The 450 Ohm feedline is 43' 4½" long, and 
connects directly to 50 Ohm coax to the equipment. I first cut the antenna 
for resonance measured at the antenna, then connected ½ wavelength (plus a 
bit) of 450 Ohm ladderline and trimmed it for minimum swr.
Results:
Resonance
10.106 Mc. swr 1.1
18.104 1.9
24.626 1.1
at 24.95 1.9
Suspecting that the close proximity (13/16" in the ladderline) of the 10 and 
18 Mc. antenna elements might compromise 18 Mc. operation, I suspended the 
18 Mc. antenna 8" below the 40 meter element in the 2'nd dipole, and there 
was NO DIFFERENCE. The 18 Mc. elements had to be 10 or so inches longer for 
resonance.
This is certainly a compromise antenna, but useful and quick.
Richard Brunner, AA1P 