RadioBanter - View Single Post - Modification of G5RV

December 25th 04, 08:09 PM

wrote:
I am using a G5RV and an Icom 756Pro II. The auto antenna tuner will
tune the antenna fine except in the area of 3963.5 and up to at least
4.0385. I use 4.0385 as a member of MARS. Right now my SWR "as
shown" is well into the "red zone".

Is there any way to modify the antenna to get it to be a better match
so that the auto tuner can do its thing. The antenna is the shortened
or Jr. version with a ladder wire lead in.

Would changing the lead in to RG8 coax be a help??

Sure will appreciate some help. I am a novice at this and it is
important that I am able to use 4.083.5.

If it doesn't have to be an all band antenna, I would change to a coax
fed half wave dipole. You wouldn't need a tuner,
except to drop farther down the band, and your efficiency would
be high. To work all bands using the ladder line, I would get a
good external tuner. But the coax fed dipole will have the better
signal on 75m by a noticable amount over the jr-g5rv. The internal
radio
tuners are not really meant to match ladder line fed antennas. I
wouldn't
try to load anything over about a 5:1 mismatch with one myself. I
consider
them as "line flatteners" mainly. IE: good to provide a wider usable
bandwidth, with an already half decent match. MK