[Antennas] Re: Antennas Digest, Vol 44, Issue 5

[VE7AJJ]

On 9/10/07, VE7AJJ <ve7ajj at gmail.com> wrote:
> > From: <k3hx at verizon.net>
>
> > Some years ago, QST had a piece on how a simple coil
> >
> > mounted between "hot" and ground at the base of a
> >
> > mobile antenna would act to match the low Z of the
> >
> > mobile antenna to 50 ohms.
> >
> > I can't locate the articla and would be grateful for
> >
> > any assistance.  I've got a 6 1/2 foot mast with a
> >
> > homebrew coil/whip that reaonates fine but has @20
> >
> > ohms of R rad.  This for 10 meters.
> >
> > 73,  Tim
> >
> >
>
>
> Some years back I used a similar set-up to what you described.  I
> tried capacitive matching at the input but it didn't work to suit me
> so I moved to the coil.  I used an air wound coil about 1 ¾" in
> diameter and it was positioned over the bottom end of the mast (which
> was also part of the working antenna.)
>
> It is a very simple task to make a lead with an alligator clip on it
> and ground the one end then use the alligator clip to move the tap
> around and locate the optimum connect point to provide best swr.
>
> There was some information in the ARRL handbook but I found it to be
> somewhat sketchy though when I actually tried to make the matching
> coil for myself I could see why the author of the information had not
> felt the need to be more in depth as it was easy to figure out by
> experimentation.
>
> Give it a try and you will see.
>
> Garry/Ve7ajj
>

Thinking about what I said about the tap.  I may have been incorrect.
I believe the end of the coild should be grounded and the feed point
connected to the alligator clip and then that can be moved about the
coil to establish the optimum SWR.

Explaining in person and writing it down sometimes comes up with two
completely different results 8>(

Garry/Ve7ajj