"Dr. Slick" wrote in message
om...
Hi,

I recently tuned up a VHF dipole, and i got
a double-dip, double resonance for the swr, and
also the minimum swr was around 1.3:1


At what two frequencies? What construction, feed type...? What method
of measurement and equipment type/numbers?

First, let's determine if there even is a problem with the antenna...



I did some modifications, and the double
resonance was was gone, plus the swr was down
to less than 1.1:1

What mods?

73,
--
Steve N, K,9;d, c. i My email has no u's.




I'm certain that one of two things (or a
combo of both) did the trick, but i wanted to
see if any of you seasoned antenna boys could
guess what the problem was.

Thanks for your input!
Slick

"Dr. Slick" wrote in message
om...
Hi,

I recently tuned up a VHF dipole, and i got
a double-dip, double resonance for the swr, and
also the minimum swr was around 1.3:1
but i wanted to
see if any of you seasoned antenna boys could
guess what the problem was.

twarnt no problem - if the dipole was 'clean' the double-dip may be due to
how close you were to it, the coax length, a nearby object, - your presence
near the antenna, the way you held your mouth while taking the measurements,
the measurement methods themselves, a passing cloaked Klingon bird of prey,
an ionized whif of exhaled air, or something none of us have ever seen.
(many causes - most just accept it is as - in Walter Cronkite's words
"That's the way it is.")


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Nilla Wafer wrote:
"Were the two halves of the dipole of equal length?"

The adjacent close-spaced wire ends have much mutual resistance and in
most cases there os a considerable conductance between them too. In
these cases, they resonate as a unit. But, imbalance enhaces radiation
from the feedline which can produce a separate resonance.

Best regards, Richard Harrison, KB5WZI

On Fri, 12 Nov 2004 10:14:52 -0600, (Richard
Harrison) wrote:
But, imbalance enhaces radiation
from the feedline which can produce a separate resonance.

Hi Richard.

However, out stellar designer has managed to negate that through a
"marijuana garden variety dipole" with radials. ;-)

I wonder who would be more interested. The DEA or the PTO?

73's
Richard Clark, KB7QHC

Richard Clark wrote:
However, out stellar designer has managed to negate that through a
"marijuana garden variety dipole" with radials. ;-)

Radials? I missed that. How are the radials coupled to
the dipole?
--
73, Cecil, W5DXP

On Fri, 12 Nov 2004 11:34:39 -0600, Cecil Moore
wrote:
Radials? I missed that.

On 11 Nov 2004 12:20:02 -0800, (Dr. Slick) wrote:
Hint: no inductive choke was needed, and the radial
lengths remained the same.

Problem: Unconventional usage leads to unconventional claims; shortly
followed by unconventional physics offered as proof in terms of
unconventional usage - familiar?

Dr. Slick wrote:
I'm certain that one of two things (or a
combo of both) did the trick, but i wanted to
see if any of you seasoned antenna boys could
guess what the problem was.

Dear Dr -

This is just a WAG, but were you supporting the dipole on an aluminum
ladder at first? Then substituted a non-metalic support?

Thanks for the interesting topic - I see it has long legs!

Lee H, NB7F
antenna boy...

Along those same lines: did you swap a metal mast for a fiberglass one?

NB7F
antenna boy