Cecil Moore wrote:
Dave wrote:
I do appreciate all of the feedback, and the patience with my ignorance.

Have you considered a screwdriver antenna? Many hams
try a whip with an autotuner, are dissatisfied, and
wind up with a screwdriver antenna for a 12 dB
improvement, at least on 3.8 MHz.


-----------


(Spoken in Columbo's voice and mannerisms)"Uh, podden me, Cec, butta,
12db improvement compared to what?"

A 108" whip tuned with an electronic autotuner at the base, on the
trailer hitch attached to an average car should be just as (was gonna
use the words efficient and effective - but thought better of it) as a
short little whip mounted in PVC pipe at the same location, but using a
mechanical tuner (screwdriver) instead of an electronic autotuner such
as an AH-4.

Yes, I have considered a screwdriver antenna, just don't know where to
put it on my minivan(s).

As you can tell, I'm coming in late on this one. Thanks for your patience.


Ed, NM2K

On Mon, 12 Nov 2007 10:51:58 -0500, Ed Cregger
wrote:

A 108" whip tuned with an electronic autotuner at the base, on the
trailer hitch attached to an average car should be just as (was gonna
use the words efficient and effective - but thought better of it) as a
short little whip mounted in PVC pipe at the same location, but using a
mechanical tuner (screwdriver) instead of an electronic autotuner such
as an AH-4.

Hi Ed,

This is a bit garbled, but the sense is there.

You are comparing a bad installation to a bad installation - yes one
will be as efficient/effective as the other.

The tuner at the base of the whip has invested resonance in the wrong
place. A coil at the base of a whip also invests resonance in the
wrong place. A coil higher in the whip invests resonance in the
better places by degree.

Ostensibly, the premium degree of coil placement is one half to two
thirds the way up the whip. A screwdriver antenna attempts to make
this resonance investment. If you will note, the coil section falls
between a lower tube and an upper whip.

There is a world of discussion as to why it is better that I will
leave to others to fill in.

73's
Richard Clark, KB7QHC

Ed Cregger wrote:
Cecil Moore wrote:
Have you considered a screwdriver antenna? Many hams
try a whip with an autotuner, are dissatisfied, and
wind up with a screwdriver antenna for a 12 dB
improvement, at least on 3.8 MHz.

(Spoken in Columbo's voice and mannerisms)"Uh, podden me, Cec, butta,
12db improvement compared to what?"

Compared to the aforementioned "whip with an autotuner".
--
73, Cecil http://www.w5dxp.com