[TenTec] Zepp?

[Rick - DJ0IP / NJ0IP]

Steve, that's a good point.

On low power it's probably still OK but real problems begin with high power.
G3UNA has done a lot of testing of the Elecraft low power switchable balun
together with his K3.
He hasn't seen any problem, although I don't like their implementation of
winding both transmission lines through a single binocular core.

I have not heard any field feedback on the higher power one yet.

That's why I find it better to use a proper 1:1 Guanella (using Teflon
coax), and switch the 4:1 in as needed, simply for its value as a
transformer.

73 - Rick, DJ0IP
(Nr. Frankfurt am Main)


-----Original Message-----
From: TenTec [mailto:tentec-bounces at contesting.com] On Behalf Of Steve Hunt
Sent: Sunday, September 14, 2014 10:42 AM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] Zepp?

Just one observation on switchable baluns - don't do it the way Elecraft
does it!

They take two separate 1:1 current baluns and connect their inputs in
parallel; then they connect their outputs in series to form a conventional
Guanella 4:1 current balun. That's fine!

But when they want it to be a 1:1 balun they connect the outputs in parallel
- unfortunately that halves the CM impedance of the balun compared to using
just one of the 1:1 baluns on its own!!!! It makes for a simple switching
arrangement, but it seems a pity to throw away all that hard earned CM
impedance.

Steve G3TXQ
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