----- Original Message -----
From: "steve d" <kc8qvo@yahoo.com>
To: <topband@contesting.com>
Sent: Tuesday, January 03, 2006 8:10 PM
Subject: Topband: New guy here. Low noise rx antenna for 1/2 acre lot?
> Hi, I just joined this forum because I am interested in Top Band. I
> figured I can learn more from you guys than the HFPack yahoo group HIHI
> (there are very knowlegeable people on there, but this forum is geared
> more towards 160). I am 20 years old and a sophmore in college. I am
> finnishing out a 2 year engineering scholarship at Sinclair Community
> College in Ohio and then will transfer to OSU this comming fall for
> Mechanical Engineering. I am currently working on WAS-160, all CW. I have
> 26 states, all but about 3 or 4 are from this season.
>
Looks like Ohio State (W8LT) still has a pretty good ham club:
http://arc.org.ohio-state.edu/index.php
They list 80-10 coverage for their HF equipment, but it looks
like the same stuff we had back in the 80's (TS-830S/TL-922),
so if you join you'll have a KW on 160 if you can get an antenna
up. If they were smart enough to keep it, there should be an old
Dentron tuner laying around with a big vacuum cap substituted
for the air variable cap in the output leg which makes a nice tuner
for 160 meters. The station used to be located in the football
stadium which had a gawd aweful high noise level. Looks like
they got moved to the west campus area. Back in the 80's that
area was pretty rural, so it might actually be a decent location for
doing 160 although I suspect its built up quite a bit since I was
there (84 - 89').
Anyway, if you get on from Ohio State you will be helping to
carry on in the tradition of past OSU lowband HF operators
including K8ND, K1LT, N8VW, KU8E, N8SM (sk), and
myself.
> OK, on to my big question here. My station is a Kenwood TS-2000 and
> 160-10m G5RV for tx/rx and a K9AY loop system (4 switchable directions). I
> have noticed that my G5RV picks up about HALF the noise that the K9AY
> loops do, and when I try to use my pre-amp (ICE, 1800-2000kHz) with the
> loops all it does is amplify the noise. The signal/noise ratio remains the
> same, if not lower because now it is louder!!! What kind of rx antenna can
> I use that will drastically recuce my noise? At times the QRN is over S9
> but it is usually around S3, and if I am luckey I can catch some noise
> levels that dont register on the S meter. These readings are with the
> preamp on the rig turned off. I dont really care what the strength of the
> signals are with the antenna or its directivity - I just want a QUIETER
> antenna! I can use the preamp to bring the level back up. I would prefer
> something omni-directional so I can hear stations equally well in all
> directions, and that also makes installing it easi
> er as
> well - no vertical elements to phase (plus I dont have the space for
> phased elements).
How high is your G5RV? You might consider a marconi or
"T" antenna whereby you short the two conductors of your
feedline from the G5RV together at ground level and then feed
this node against some kind of ground radial system. With a
good complement of radials (20 to 30) this will make a pretty
good TX antenna (much better than a low horizontal antenna). .
As far as the RX antennas go, are you seeing any front-to-back
on the K9AY loops? I installed a similar system (switchable in
four directions) at one of the local club stations near my
home here in Los Angeles. Performance isn't stellar, but I do
see signifcant front-to-back. I also seem some noise reduction
when beaming NE or NW as compared to when I beam SE or
SW which makes sense in this case since the area is towards
the south from the antenna location is much more heavily
populated than the area to the north. The other thing that I find
is that signal strength on any given received signal is generally
nearly equal in 3 directions of the 4 directions available and
only down in 1 direction relative to the other 3. This is consistent
with the azimuth pattern of the K9AY loop as it has a very
broad main beam (almost no front-to-side) with a narrow null
off the rear. In any case, if your not seeing any change in signal
levels when you switch directions, then something is wrong with
the system. That should be first on your checklist.
Good luck & 73,
Mike, W4EF (OSU class of 89').
_______________________________________________
Topband mailing list
Topband@contesting.com
http://lists.contesting.com/mailman/listinfo/topband
|