[Antennas] Interaction Between 40m Attic Dipole and Cable TV Coax

Wed, 5 Nov 2003 10:59:32 -0600

Merv,

  This is not a TVI issue. And, I completely agree with your statement
regarding the difference in SWR (I've done those sorts of calculations
before and have seen the numbers).

  My primary concern is actually in the shift in resonance of the antenna
due to the mutual coupling. Even with the cable TV coax disconnected, the
40m antenna is not resonating where I want it to (too low). My concern is
that when I do get a chance to get up there and tune the 40m section, I may
very well find that as I try to center the antenna's resonance, the minimum
SWR will continue to climb due to the interaction. Therefore, I thought I
would try to gather some information on the issue ahead of time just in case
I have problems when I do manage to get up there and tune the antenna.

  Thanks! -Michael N9BDF

-----Original Message-----
From: Merv Stump [mailto:[email protected]]
Sent: Wednesday, November 05, 2003 10:45 AM
To: 'Linden, Mike (BRC-Hes)'; [email protected]
Subject: RE: [Antennas] Interaction Between 40m Attic Dipole and Cable
TV Coax

Michael, if you are attempting to resolve a TVI problem then you may
have no choice except to pursue this.  However, if your goal is simply
to get your swr down from 1.4 to 1.2 then I assure you, you are wasting
your time.  To begin with I submit that the difference between 1.4 and
1.2 is within measurement error of most amateur equipment.  Even if
these measurements are accurate neither you nor your equipment will ever
know the difference.

Regards, Merv W2OE