[Johnson] Matchboxes in general

[Richard Peterson]

Bob:

I’ve owned the Johnson Matchbox Jr. and a friend of mine owned the Johnson 
KW version. Now, bear in mind what follows is personal experience. I am not 
an engineer.

The matchboxes are beautifully built. Mine had too many screws because, in 
the early days of TVI, they thought they had to shield the tuner. Wrong.

It was my experience that the Jr. had a little more tuning range than the KW 
version. Other hams have said that, too.

But remember when they used to talk about tuned feeders? Have you see the 
tables in the old ARRL Handbooks that show what feedline length you need to 
use with your center fed, ladder line antenna?

That’s because the old-style balanced tuners (like the Matchboxes) would not 
always handle any random feedline length. Their tuning range is pretty 
limited. My Jr. and my friend’s KW wouldn’t tune many loads unless we fussed 
with adding additional L or C. It was a major pain in the butt.

Yes, they will offer balance. That is nice, but not always necessary. And I 
even ran a test … I used my Junior in a 40 meter QSO, took it out, and went 
to my home-brew high-pass T network that was unbalanced. Nobody on the other 
end could tell any difference at all. And that T network will match anything 
I have thrown at it.

If you can put up a feedline that is a specific length, and an antenna that 
is a specific length, the Matchbox will work. Else, it will work on some 
bands, and not others; or it will work on all bands; or it will work on NO 
bands at all.

The T network is the most common commercial unit today, and actually the way 
to go, in my view. But not all commercial units are T networks, and I am not 
an authority on what is out there.

Lew McCoy (whom I knew – he used to live here in Silver City, NM) led the 
direction toward T networks with his Ultimate Transmatch, which is a 
modified T. In truth, that is what I use. Recently, I have used a really 
large balun that I built and tested and it does provide some decent balance 
from 160-20, but I could never make a balun that would work properly from 
160-10. But that’s no big deal.

Why do I use a balun? Beats me. But it might keep the RF field down a little 
bit in my operating position.

And yes, it can handle the power – I run my Johnson Desk through it.

I hope this helps a little bit.

Richard, WB5NEN



From: Robert Nickels <w9ran at oneradio.net>
To: Richard Peterson <zapp11 at hotmail.com>
Subject: Re: [Johnson] Thirty years of ladder line
Date: Mon, 24 Oct 2005 22:27:35 -0500

Richard Peterson wrote:

>Not to beat this issue to death, but I like ladder line, and once you've 
>used it, you will really like it.
>
>But I agree with the warning that using metal standards to support it is 
>not the best idea. I think a good tuner will overcome that, however...but 
>remember, a Johnson Matchbax has a fairly limited tuning range compared 
>with the more modern high-pass T networks that so many of us use.
>
Hi Richard,

As one who's hoping to put his first ladder-line fed antenna up yet this 
fall, this thread is timely for me as well.  I'd be interested in 
recommendations for KW tuners, as I'd been thinking the Big Johnson (!) was 
the one.

Thanks and 73,
Bob W9RAN