On 1/14/2011 1:05 PM, Rick - NJ0IP / DJ0IP wrote:
> These are not as good today as their reputation was 40 years ago.
> The reason is, we've got more bands to match today, and our transceivers
> demand darn near 50 Ohms.
> The models were 275w and 1KW.
> I had the KW version about 45 years ago.
> Bought the small one about 2 years ago and didn't keep it long.
> The little MFJ-974B (for under $200) was far superior to the Viking in its
> matching range.
> Had the two side by side and used them with several different Openwire fed
> With the mods Jerry did to his Viking, they will match just about anything.
My first "Johnson Matchbox" was not made by E.F. Johnson, it was made by
G. N. Johnson, that is ME. It will match most anything from a short to
an open and I've used it to test twinlead that way.
Were I to have to use an E. F. Johnson Matchbox, I'd be tempted to
change the circuitry making the link effectively variable with a series
variable capacitor on the link ground, maybe change the differential
caps to a switch selecting half a dozen secondary coil taps. I might
have to add a switched padding capacitor for the secondary tuning
capacitor after removing the differential caps. Then maybe I would
prefer to invent a totally different scheme from all that have been made
and that are on the market including automated remote control and
coverage from 500 kHz (maybe 135 kHz) through 146 MHz.
> A much better box is the Annecke, which L.B. Cebik compares (very favorably)
> to the Johnson in his article about link coupled tuners.
> The Annecke had more taps, especially on the TX side, as well as an
> additional variable capacitor on the TX side.
> It was also available in two versions; 200w and 1KW.
73, Jerry, K0CQ
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