Stuart: et al
I too find most internal tuner baluns to be over rated, especially in
complex Z conditions. Thus, I've found the external balun from Amidon, being
the W2FMI model rated at some 4 KW, to be quite good. I connect it to the
tuner by a short piece of coax and the balanced feed goes out from there.
I've never observed any heating or SWR changes regardless of power and
antenna configuration with this combination. Even when running "legal
limit" high level modulation on AM which I frequently do.
To that end, I've tried a couple of other popular "legal limit" tuners on
the AM rig. Under those conditions one will quickly find out if the tuner
can handle legal limit power otherwise it is "smoke and fire". Legal limit
SSB is one thing as the duty cycle is quite low. Hang a legal limit high
level modulated AM transmitter on the input of the tuner and you'll find out
soon enough if it can handle "legal limit" or not. Most can't.
73
Bob, K4TAX
----- Original Message -----
From: "Stuart Rohre" <rohre@arlut.utexas.edu>
To: <tentec@contesting.com>
Sent: Tuesday, July 01, 2003 11:27 AM
Subject: Re: [TenTec] T tuner (transmatch) losses?
> That is consistent with the tuner measurements article in QST some years
> back.
> Murch was a rugged component tuner. Still good if you can find one.
Most
> tuners are limited by goodness of the balun. For lower loss, at Field
Day,
> we used external 4:1 baluns after the coax output jack of tuners and then
> ran into 450 ohm or 300 ohm ladder line.
>
> Also see Tuner loss tests in QRP-l archives reachable from "QRP-ARCI
> webpage" found by google.com search.
> 73,
> Stuart K5KVH
>
>
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