On Mon, 30 May 2005 23:20:27 -0500, Cecil Moore
wrote:

Gary wrote:
I just constructed a homebrew G5RV, 51' on each leg, 32' 9" for the
ladder line matching section.Then there's about 10 turns of RG8X in a
6" dia. coil for a RF choke. It's in an inverted V configuration. It
seems to work well enough on 80 and 40 meters, but the SWR on 20
meters seems a bit high. It's 3:1 at 14.001 and seems to climb
somewhat higher at 14.349. I made the matching section 32' 9" should I
trim some off of the matching section, say down to 32' even or leave
well enough alone ? I can tune it to 1:1 with my manual tuner, though
the best the autotuner can do with it is about 1:6 to 1. I would like
to have it resonant on 20 just because that was the band it was
designed for IIRC.

If the SWR climbs from 14 to 14.35, then the matching section
is too long and resonates the antenna system below 14 MHz. My
matching section is 29 feet on 14.2 MHz using "450" ohm ladder-
line (closer to Z0=388 ohms). But don't expect the get the
SWR much lower than 2:1 on 20m where the antenna is 1.5
wavelengths long.

Ok, thanks Cecil. I suspected the matching section was too long
because as you said the SWR rose the higher I went in frequency. I'll
trim a foot or so off of it. Its not important but I don't know why
the autotuner can only tune it to 1:6 to 1 as I mistakenly tuned 80
into my 20 meter dipole with not much problem. Maybe the letters MFJ
have something to do with it

73 Gary K8IQ