Greetings to all,
Sorry its taken so long to get back to everyone concerning my problem
with the horizontal loop that I put up to replace my dipole, but I've
spent more time traveling in the last month then normal. I had a lot of
suggestions as to what the problem might be and things to check. What I
found to date is a bad ground wire from the tuner. By replacing it I
was able to tune the antenna up from 10 through 40 meter, however, I
can't get the tuner to handle either 80 or 160m. I'm going to try and
add some additinal length to see if that will help. I can't see where
there is any arcing or shorts within the tuner or the antenna. I'm also
ordering out a 4:1 balun to place into the line to eliminate the balum
in the tuner. There have been a couple of cases where the balum seem to
shut down, I think, because I will transmit, the swr goes thru the roof
and it sounds, on receive, like I'm listening thru a 40' pipe. I wait
about 5 minutes and the reception comes back to normal, but it remains
normal on my other antenna. I haven't been able to find a short or cold
solder joint anywhere. Just for information, with the dipole, I fed it
with RG-58 stright into the tuner, whereas, with the loop, the
ladderline runs into the tuner.
Thats where I'm at for now, I'll update everyone more as things
progress.
I would like to thank Pete, KS4XG, Jerry, NO2T, John, N3HBX, Rick, N6CR,
Ken, K4XL, LB, W4RNL, Scott, N1SP and Ed, NA5B for all their suggestions
and comments. Again, sorry about how long its taken to get this far.
73,
Bob N8YGG
Original Message........
I'm having a problem with either my antenna tuner or with my antenna. I
recently replaced my 265' dipole, fed with coax, with a 270' horizontal
loop, fed with 450 ohm ladder line. Iwas able to tune the dipole to
work all bands but with the loop and the ladder line i can't load the
antenna on any band. When adjusting the tuner, it seems to act strange.
Its a Vectronics model vc300, sold by a local hamshop with their own
label. The inducter and the transmitter controls seem to have some
effect but the antenna control has no effect. After getting the swr
down to 1.6 or so,with 10 watts and I move to 100 watts, its shutting
down the transmitter and the swr meter goes off the scale. I've tried
to tune the loop on all bands from 10-160 with the same effect. I
talked to the ham shop and they have never heard of a problem with
tuning ladder line. I've e-mailed a message to Vectronics and haven't
gotten a reply. I've checked the loop and there isn't a break in the
wire. Any ideas? Should I change tunners? If so, what do you
recommend. I read the thread before on the MFJ-939s and it doesn't
sound like they are highly though of. The local shop has a Heath Kit
model 2040. would that be better?
Thanks for the time and sorry about the bandwidth, but I'm not sure of
what to do.
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