[Heathkit] foldback

Fri, 10 Oct 2003 12:14:11 -0400

Carl, if you refer to the following response you gave:

------------------
"There were several changes to the input circuit to improve the VSWR. These
were published in various contest and DX magazines once SS xcvrs became
popular.
If no one else has something handy let me know later in the week and I'll
try and dig them up."
------------------

I did not find that your post contained any helpful information, just vague
reference to vague publications.  If you made any suggestions to help the
man with his input VSWR problems, they have not shown up here.

Because you obviously know more than Measures and because I am in the
process of reworking an SB-220, I would like to know your ideas on improving
the input VSWR of my amplifier.

73, Mike N4NT

----- Original Message ----- 
From: "Carl" <[email protected]>
To: "Mike Hyder --N4NT--" <[email protected]>; "Heathkit
Reflector" <[email protected]>
Sent: Friday, October 10, 2003 11:49 AM
Subject: Re: [Heathkit] foldback

>
>
> > Perhaps you could shed some light on the SB-220 input impedance problem
>
> I already did but I guess you didnt bother reading that post.
>
> > instead of just bashing someone else.
>
> Trying to present a balanced discussion is now called bashing? Gee and I
> thought the purpose here was to help people and possibly not make
expensive
> mistakes. Sorry, go on your merry way ostrich style.
>
> I have found Rich Measures to be of
> > much more help than QST.
>
> He has some good advice.
>
> >
> > And considering most of the stuff in QST, it is probably a high honor
NOT
> to
> > be published there.
>
> Obviously you are totally clueless what transpired and are not interested
in
> anything but QST bashing and your own beliefs.
>
> Enjoy yourself
>
> Carl
>
>
> >
> > 73, Mike N4NT
> >
> > ----- Original Message ----- 
> > From: "Carl" <[email protected]>
> > To: <[email protected]>
> > Sent: Tuesday, October 07, 2003 10:37 PM
> > Subject: Re: [Heathkit] foldback
> >
> >
> > > 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