As I have been told, the Johnson Matchbox was rated for AM, double sideband,
full modulation. I would think that it would be able to used with moderately
more power for SSB, but since I am not an engineer, I can't say that with
final authority! For balanced lines and balanced antennas, they are great,
although their matching range is a hair on the narrow side. Not lossy like
tuners with baluns (it's usually the balun that gives you alot of loss, and
the balance in a balun is not as perfect as the old link coupled tuner). For
coax, ther "L" is king. VERY, VERY low loss and with enough inductance and
capacitance, you can match about anything. But you will definately need alot
of capacitance (that is why Ten Tec has a space on the back of their tuners.
You can add more capacitance externally if you need to. Especially on 160).
Just remember, when talking tuners, look at what the QRP guys use. They need
the lowest loss possible so they use the lowest loss components. What works
well for QRP works well for QRO (it just takes BIGGER components). Vern
N2YZS
----- Original Message -----
From: "Carter Grabarczyk" <k8vt@ameritech.net>
To: <tentec@contesting.com>
Sent: Tuesday, July 01, 2003 9:36 PM
Subject: Re: [TenTec] T tuner (transmatch) losses?
>
>
> denton wrote:
> > Too bad no one is making the old link coupled transmatches anymore...I
have
> > a Johnson Matchbox..the 250 watt version...that I use for a basis of
> > efficiency testing.
> > Nothing I have ever homebrewed or anything commercialy available
nowadays I
> > have tried can really match the balance or efficiency ability of the old
> > Matchbox, as far as matching to either one of my delta loops fed with
450
> > ohm ladder line.
>
> I also have a Johnson (well OK, a Nye Viking *identical* clone) 250 watt
> matchbox with SWR bridge. As these were fairly beefy and built in the AM
> days, does anyone know what power it can take on SSB, RTTY and CW or is
> 250 w really it?
>
> Thanks,
> 73/Carter/K8VT
>
> P.S.
> It followed me home from a (non-ham) flea market. A CB'er was selling it
> and the CB rig together for $15. I asked him if he would take $10 for
> the tuner and he could keep the rig. We both walked away happy! <g>
>
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