[TenTec] Optimizing 238 settings?

Joel R. Hallas jrhallas at optonline.net
Mon Dec 28 06:29:42 PST 2009


I can't think of a reason that they wouldn't. In fact it is even more
important with a T match, since there are an infinite number of combinations
that can provide a match. The point is that the wire in inductors has
resistance that contributes to loss, while an air dielectric capacitor has
much less loss. Thus less inductance generally means less loss, all else
being equal.

Someone mentioned that measuring the output is an even better way to be sure
you have the best settings. While they suggested a wattmeter (the
calibration will not be meaningful since it is not a 50 ohm system at the
output of the tuner), a better choice might be a relative current indicator
such as the simple one described in the Sept 09 QST article by Paul Danzer,
N1II. MFC also offers an RF ammeter, and there used to be many at hamfests
from WW2 equipment. Using a transformer to couple to a pilot bulb can also
work, and doesn't steal much power. If you have a balanced output, having 2
meters or transformers will allow you to check balance as well. 

It's also worth reading the article "Keeping Current with Antenna
Performance," by Eric Nichols in Feb 09 QST. He actually proposes the idea
of not worrying about the match between the tuner and radio as you maximize
tuner output, although that does have some risks. 

Regards, Joel
Joel R. Hallas, W1ZR

-----Original Message-----
From: tentec-bounces at contesting.com [mailto:tentec-bounces at contesting.com]
On Behalf Of Richards
Sent: Monday, December 28, 2009 4:29 AM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] Optimizing 238 settings?

Do these "rules" of thumb about how to tune an L-match
tuners apply to other tuners, such as Palstar T-match tuners?

I.e., pick the lowest inductance where one gets a good match,
or the one with the highest capacitance relative to inductance.

Thanks.  =========  K8JHR  ==============

> On Sat, 26 Dec 2009 10:39:12 -0500, Joel R. Hallas wrote:

>> Rule 1 is use the minimum inductance. 

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