Ron, the screwdrivers I'm familiar with out of the 50's and 60's were not
motor driven.
Weren't they called Bandmaster or something like that?
The motorized ones didn't come about until much later.
Placing the coil at the bottom induces a huge degradation in performance.
It would significantly lower the radiation resistance, causing the impact of
ground resistance to be much more severe.
Not a good idea.
73
Rick, DJ0IP
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Ron
Notarius W3WN
Sent: Saturday, November 09, 2013 10:58 PM
To: 'Discussion of Ten-Tec Equipment'
Subject: Re: [TenTec] 160 M antenna
How could this be the forerunner to the "screwdriver" mobile antenna?
His article was published circa 1986, and screwdriver mobile antennas go
back to the 1950's & 60's!
That said...
I could forsee mechanical problems mounting a "screwdriver" at the top of
the antenna, but what if it's at the bottom?
73
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Steve Hunt
Sent: Saturday, November 09, 2013 4:51 AM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] 160 M antenna
Rick,
That's correct!
The only published article I know of was by Tim Forrester G4WIM in RSGB's
RadCom - later included in their book "HF Antenna Collection". In addition
to the basic top-loading principle, Tim described in detail the mechanical
arrangements for the auto tuning whip: a geared motor drove a lead screw
that progressively introduced a core into the loading coil.
Tim won an RSGB award for the article - the design was in many ways a
forerunner of the "screwdriver".
73,
Steve G3TXQ
On 09/11/2013 09:13, Rick - DJ0IP / NJ0IP wrote:
> Steve,
>
> I don't understand what you are describing.
> I think you mean placing a screwdrive-tuned mobile whip on top of a
> metal lower section.
> Correct?
>
> I have never seen or read about this.
> Do you know a source where we can read more on this?
>
> 73
> Rick, DJ0IP
>
>
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