Hi Robert,
Won't work.
If you look at the insides of the JVM you will notice that it is built
(physically) symmetrical.
If you want to use the roller inductor and maintain the symmetry, you would
have to find a mechanical way for the shorter link coil to fit around the
roller coil and move back and forth with it.
That is basically impossible.
The best way to get better coverage on those two WARC bands is to apply the
mod I describe on my web, here:
www.dj0ip.de/antenna-matchboxes/symmetrical-matchboxes/j-viking-upgrade/
In the past, I have played with the taps on my Annecke (which is
fundamentally the same as the Johnson) and for 40m, moved the two 40m taps
about 1/2 turn towards the middle of the coil. This reduced the inductance
slightly and enabled me to get a better match on 30m.
I did the same for 17m but moved the taps a half turn towards the inside on
20m.
If that doesn't work, then move the 15m taps a half turn towards the
outside.
What works best depends on the impedance of your antenna as seen at the
shack end of the feedline.
This worked for me but the Annecke already had the mod described in the link
above.
I have never tried this on a JVM.
You must be very careful when soldering these coils. Don't melt them.
73 - Rick, DJ0IP
(Nr. Frankfurt, Germany)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Dry Martini
Holding Company??
Sent: Monday, July 25, 2016 1:07 AM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] OT: Question to the group
Rick,
I have a JVM, and it is working well for me on all but 30 and 17m. I
recently bought a roller inductor to build a McCoy transmatch. However,
could I replace the coil in the JVM, and would this more trouble than it is
worth?
Tnx,
Robert
KG4KGL
> On Jul 18, 2016, at 12:00, rick@dj0ip.de <Rick@dj0ip.de> wrote:
>
> FULL AGREEMENT GARY, EVERY WORD.
>
> RECOMMENDATION TO ALL: if you can find a good JVM, buy it. You'll never
regret it.
>
>
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