[TenTec] Open Feed Lines

[Robert & Linda McGraw K4TAX]

Gee, I feel short changed.  I run my balanced feed line up the tower which
has my TV antenna mounted on the side.  The nearest VHF TV station is 85
miles away.  No TVI here, any band, any mode and any power that the
Centurion will produce.

A point on Balanced Feed and baluns.  Most folks don't take the time to
really construct and erect a truly balanced system.  This is problem 1.
Then there's the case where the  little balun in most, yes MOST, tuners is
really inadequate for their stated power levels in the face of a complex Z
which is offered by all non-resonate antenna systems.  For that reason, I
will only use a balun rated at a minimum of  5 KW and the one on my "legal
limit" AM station is rated at 10 KW!  If one wishes to run power, be sure
you have the hardware to handle it.

As to CATV interference, well their signal is supposed to stay "inside"
their cable and it is not supposed to let any outside signal in either for
that matter.  If it does, it's there problem and if a signal gets in from
your station you can bet one is getting out. Illegally!  No questions ask,
no hold barred, it's their problem.  You can bet your sweet bippy that if
the CATV signal interferes with my weak signal VHF or UHF work I'll be all
over their case in a heartbeat.   In one case it did, I wrote several
letters to the CATV folks with no response.  Finally I reported the issue to
the FCC.  The CATV company got a nice letter from the FCC and you'd be
amazed at how many CATV folks showed up in my neighborhood.  Amazingly, the
VHF and UHF CATV radiation got cleaned up too.  Funny how that works.

Finally, if you have problems with RF in the shack, TVI, and etc when using
open wire or balanced feed systems, you need to do some antenna work.  If
changing to coax corrects the problem then that proves that you did not have
a balanced system.

73
Bob, K4TAX


----- Original Message -----
From: "Tom North" <tomnorth@airmail.net>
To: <tentec@contesting.com>
Sent: Thursday, October 17, 2002 11:09 AM
Subject: [TenTec] Open Feed Lines


> Given all the hoorah, I'll add my .02 worth -
> Late last Spring I relocated to my current QTH, which afforded me the
> ability to run abt 100M of loop, very stealthily (yes, I live in one of
> THOSE neighborhoods) from rooftop and thru the trees in a very 'open'
shape.
> I also ran a multiple rod dedicated RF ground for the shack in my yard,
> concealed pretty well in shrubs and ground cover. The feed was a 50' run
of
> window from the balun output of the MFJ-949e to feedpoint. In short,
tuning
> was unimpressive, and sharp in places. RF talked to many things in the
> house, including my PC, printer and smoke detectors. Switching out to
RG-58
> and placing a hb balun at the feed settled things down nicely.
> More recently the PoS grade MFJ got upgraded to a Dentron Super Tuner.
Again
> I went back to see what was up. The only real improvement with the open
feed
> was less tendency for the tuner to saturate on low bands if not within a
> reasonable SWR, attributable to the Dentron, no doubt. Back to the RG-58.
> With the Dentron & loop I can even get an acceptable SWR on 160M, which is
> as it should be. My house is RF quiet.
> I don't care to recall how many times I've read-to-sleep abt the pro's,
> con's and qualities of either method of feed. What I do know is that in my
> situation, I can hear and get out when a band is open. Everything in the
> house and 'hood is happy. Relative line loss and a lot of other things
> become very secondary.
>
> and that's my story, and I'm stickin' to it . . .
>
> 73,
> Tom North  N5OZQ
>
>
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