[Towertalk] Tribander anomaly

Mark Mark <AA6DX@arrl.net>
Wed, 08 May 2002 20:08:14 -0700


My humble suggestion .. if it is relatively convenient to do so,   --- well
heck even if it ain't ..spin the lower aerial 90 degrees, which will
change -- not necessarily fix-- the mutual admiration society .. and, then,
let us know .. 73 .. Mark, AA6DX
----- Original Message -----
From: "Jim White" <k4oj@tampabay.rr.com>
To: "W4ZW" <w4zw@comcast.net>; <towertalk@contesting.com>
Sent: Wednesday, May 08, 2002 2:52 PM
Subject: Re: [Towertalk] Tribander anomaly


> can you easily swap feedlines - can you take an out[put rating of exactly
> 100 W at the stn and then see if the saem number of resulting watts exist
at
> the end of both of the coaxes?
>
> I woulod suspect the feedlines - altho the 40-2CD is notorious for being
to
> load up on almost any band!  We have used it to spot multipliers on 20
> meters while the main rig was on the 20 meter stack...
>
> K4OJ
>
>
>
> ----- Original Message -----
> From: "W4ZW" <w4zw@comcast.net>
> To: <towertalk@contesting.com>
> Sent: Wednesday, May 08, 2002 4:01 PM
> Subject: [Towertalk] Tribander anomaly
>
>
> >
> > I have an antenna/tower question for a change of pace.
> >
> > I discovered quite by accident that 15M signals are better on my 402CD
> > CC 40M beam  than on either of the A4S tribanders I currently have up.
> >
> > I was listening  to a pileup the other evening on 15m and realized I was
> > on the 402CD.  Switched to the A4S which is 12' below it and the signals
> > dropped a full S unit.  Wow, that's strange.  I just recently rebuilt
> > all the antennas that were pretty much destroyed in a tropical storm.
> > New aluminum, hardware and feed lines.
> >
> > The 402CD is rebuilt and on a Glen Martin rooftop tower about 70' above
> > ground which is about 18' above sea level in my back yard.  I'm ocean
> > front directly on the Gulf of Mexico on the southern tip of an island
> > with ocean and bay in all directions except NNW.
> >
> > I switched to my second A4S (not rebuilt, but one I kept in the garage
> > for Field Day) that is on a Rohn mast about 6' lower than the first A4S
> > and about 35' away  to the SSE.  Same signal level as the first A4S.
> > Switched back to the 402CD and the DX signals pop up out of the noise.
> > Does the capture area of the 402CD make that much difference?  My wire
> > antennas are still down so I can't compare there, but as soon as the 80M
> > Bob tail and the full wave delta loop are be back up I intend to explore
> > them as well.
> >
> > SWR on both the A4S's are essentially flat 1:1.  They are super on 10
> > and 20 compared to the 402CD, but on 15M the 40CD2 is clearly the better
> > receiving antenna.    The 402CD has a 2.6:1 SWR on 15M and is easily
> > loaded with the auto-tuner on the FT-1000D.  Of course it loads pretty
> > well on 12M and 17M as well.  Maybe the 402CD should be called a
> > quadbander, hi!
> >
> > Any ideas?
> >
> >
> > Jon Hamlet,  W4ZW
>