[Heathkit] foldback

Tue, 7 Oct 2003 22:37:18 -0400

You may want to read the series of rebuttals by real engineers in QST about
the Measures articles. And that he has been banned from future publication
there.
I consider most of his parasitic theory pure garbage and have proven it time
and again to skeptics. This is old news as it took place on the AMPS
reflector several years ago.

Carl
KM1H

----- Original Message ----- 
From: "David Cook" <[email protected]>
To: "'Jim Brannigan'" <[email protected]>; <[email protected]>
Sent: Tuesday, October 07, 2003 9:48 PM
Subject: RE: [Heathkit] foldback

> Wow, what a great paper! I recently acquired the first amplifier I've ever
> owned, an SB-200. I put in all the Harbach mods, but still didn't
understand
> much about it. Many of Rich's explanations of the design decisions and
> performance considerations for the SB-220 apply to the SB-200. Thanks for
> posting this link. I'm going to fire off an e-mail of appreciation to Rich
> as well.
>
> 73, Dave, WA�TTN
>
> > -----Original Message-----
> > From: [email protected]
> > [mailto:[email protected]]On Behalf Of Jim Brannigan
> > Sent: Monday, October 06, 2003 2:38 PM
> > To: Hotmail; [email protected]
> > Subject: Re: [Heathkit] foldback
> >
> >
> > This is Rich Measures' site.  There is a wealth of information on the
> > SB-220.
> > http://www.somis.org/sb220ci.html
> >
> > The SB-220 was designed when most exciters were tube based
> > with a pi-network
> > output.  The pi net output is able to match a wide range of
> > loads and the
> > input impedance of the amplifier was not a serious design
> > consideration.
> > Many Solid state exciters are not as forgiving and some
> > attention to the
> > amplifier input impedance is necessary.
> >
> > Jim
> >
> >
> > ----- Original Message -----
> > From: "Hotmail" <[email protected]>
> > To: <[email protected]>
> > Sent: Sunday, October 05, 2003 12:10
> > Subject: [Heathkit] foldback
> >
> >
> > > I have a great SB220 with the latest Harbauch mods that I installed.
> > >
> > > Question:
> > >
> > > My exciter (TS140S) folds back to 50 watts out on 10
> > meters. How do I go
> > about tuning the amplifier (input circuit I guess) to
> > eliminate the foldback
> > issue or is this normal?
> > >
> > > Thank you,
> > >
> > > Bruce
> > >
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