[TenTec] KW 107 Supermatch

[Dr. Gerald N. Johnson]

Yah, I'm going to LEAP in here. First its Jerry, not Gerry. Its been 
Jerry all my life and I'm not changing now on my 69th birthday. I don't 
know my mother's reasoning, but that's the way it is. I do answer to 
Gerald, but generally not on the ham bands. At home being called Gerald 
generally was a precursor to unpleasant events.

I've not used the Z-Match ever. I can see the problems with loaded Q 
depending a great deal on frequency and load Z. I know I've heard WA0ROI 
(owner of a wall full of Tentecs and Cubics) mention more than once he 
like the Z-Match tuners of old, thought they had great versatility. But 
I doubt the one he used long ago would handle his PA outputs now.

In crowded RF environments like big cities and all of Europe I like the 
concept of more tuned circuits in front of the receiver. Because no 
matter how great the receiver's dynamic range it can perform better with 
less out of band RF on the front end. It still can't hack another ham in 
the same block on another band or the same band, the best receiver isn't 
that good. Then tuning reduces transmitter mixer spurs and harmonics. 
While rigs meet regulations, sometimes the neighbor still sees the 
harmonics because only 50 or 60 dB down isn't weaker than the signals 
the neighbor wants to watch on TV.

73, Jerry, K0CQ

On 2/18/2011 11:51 AM, Rick - NJ0IP / DJ0IP wrote:
> Tom,
>
> First of all, if I say "yes", Gerry will jump in my case!  ;-)
>
> This is a clasical Z-Match - the 2-coil version.
> It is the high power version built about 30 years ago (or more).
> It was designed for openwire from the get go and is pretty good for matching
> typical open wire antennas.
> Like the Viking, it adds selectivity, which is useful for the receiver and
> for suppressing harmonics.
> However with today's good receivers (the good ones), you don't need it for
> that reason.
>
> It has no bandswitch, so that is one less source of trouble.
> Instead it has two sets of connections for the openwire.
> You have to move the feedline back and forth to change from 80/40 and
> 20/15/10.
> However, if you have some wild impedances, it can happen that you need to
> use the other input - generally only true when working 40m or 20m.
>
> It also tunes the WARC bands, matches them quite well.
> Which input 30m uses depends on the antenna.  Can go either way.
>
> Sounds good up to this point.
>
> However, when you get impedance extremes, this box has an awful lot of loss.
> They were condemned by many people because of this.
> As long as you know that and make sure your antennas are never more than
> about 1000 Ohms, they work OK.
> You do that by changing feedline lengths.
>
> The answer to your question depends on the price.
>
> A better box in my opinion is the big MFJ Symmetrical matchbox.
> If the auction price comes anywhere close to that, go with the MFJ.
>
> Maybe Gerry has some other reasons why not to use a Z-match.
> I'm sure Steve is quite familiar with it; probably more than the rest of us.
>
> At the end of the day, there is theory and practice.
> I have the low power version, the KW EZEE Match, and I'm not parting with
> it.
> I haven't used it for 20 years, but I'm keeping it as a backup symmetrical
> matchbox.
>
> When I was using it regularly, I used it with:
> - 2x 13m doublet
> - 2x 17m doublet
> - 2x 20m doublet
> - 84m Horizontal Loop
> - 42m Horizontal Loop
> - Vertical Dipole (2x 5m)
>
> Our club(s) turned in lots of good field day results with these antennas
> (especially the loop), using that Z-match.
> I had lots of successful mini-expeditions with these combinations.
>
> There are better matchboxes.
> Some are expensive, others are not to be found (because nobody parts with
> them [think "Annecke"]).
>
> 73
> Rick
>
> -----Original Message-----
> From: tentec-bounces at contesting.com [mailto:tentec-bounces at contesting.com]
> On Behalf Of tom stewart
> Sent: Friday, February 18, 2011 11:48 AM
> To: TenTec at contesting.com
> Subject: [TenTec] KW 107 Supermatch
>
> Is this a good tuner for balanced lines? Is it worth pursuing?
>
> Thanks- Tom N7ESE
>