Re: RTTY or CW to check SWR on 7000 I am having problems


Steve Sawicki
 

Mac,
Do you remember the size and number of turns for the High Sierra HS-1500 coil?
Not easy to "find" higher voltag equality MICA caps.......

Regards.
Steve
AB2ET/4

--- In ic7000@yahoogroups.com, D C *Mac* Macdonald <k2gkk@...> wrote:


The matching device needed is simply a coil with the
proper inductance SHORTED from the feedpoint to the
chassis ground. This coil along with a small portion
of the loading coil of the antenna forms an "L" network
to match the very low impedance on 40 and even lower
on 75/80 meters to the 50 Ohm impedance of your coax.
It is virtually lossless.

A fixed capacitor at the same location will also serve
to get you a correct match. Try 1,000 or 470 pFd for
75/80 and 470 or 270 for 40. It's been so long that I
have forgotten the actual starting values. Use good
quality MICA caps, the higher voltage rating the better
(within reasonable phyisical size limits).

With the High Sierra HS-1500 (replaced by HS-1800)
one coil is used for all bands from 80M through 10M.

The old Master Mobile (60s and 70s) setup, there was
a manually variable inductor in the same location that
could be reset for each band. I still have that setup
(that I bought in 1962) out in the garage with lots of
other old stuff.

If you don't need help to match your antenna to 50
Ohm coax, you have an antenna that is excessively and
unnecessarily lossy!

73 - Mac, K2GKK/5
(Since 30 Nov 53)
Oklahoma City, OK

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