[Boatanchors] Electronic TR Switch?

[Ed Swynar]

Hi Vic,

A low pass filter may well be the answer to solving the TVI problem, but
there's still the matter of all those other nasty harmonics in between!

A solution would be the use a half-wave filter for every band you transmit
on, and / or a good transmatch between the rig & the antenna...the
alternative is having guys answering your CQs on 14.010-, 21.015-,
28.020-MHz, etc., all while you're transmitting on 7.005-MHz...!

~73~ Eddy VE3CUI - VE3XZ


----- Original Message -----
From: "Vic Rosenthal" <vic at rakefet.com>
To: <boatanchors at mailman.qth.net>
Sent: Sunday, May 01, 2005 5:06 PM
Subject: Re: [Boatanchors] Electronic TR Switch?


> mikea wrote:
>
> > But it's an _active_ device, with a vacuum tube in it, and if the grid
is
> > driven positive, then it's no longer linear: it stops acting like a
piece
> > of copper. Instead, it changes those pretty sine waves to something non-
> > sinusoidal, with all those rich, chunky second and third harmonics that
the
> > local TV-watchers have come to know and love.
> >
> > That's all it takes, and some (not all, but *SOME*) of the tube-type TR
> > switches are known for exactly this behavior, as the original note
stated:
>
> And the solution, then and now, is a lowpass filter between the tr switch
and
> the antenna.  The mechanism that generates harmonics here is exactly the
same as
> the one in a class-C amplifier.
>
> --
> 73,
> Vic, K2VCO
> Fresno CA
> http://www.qsl.net/k2vco
>
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