[Boatanchors] 1930's era cw transmitter

[Jbrannig at verizon.net]

Putting a variable capacitor in series with the grounded end of the "antenna 
link" made matching a breeze.

Jim

-----Original Message----- 
From: Bry Carling
Sent: Sunday, June 02, 2013 9:47 AM
To: boatanchors at mailman.qth.net
Subject: Re: [Boatanchors] 1930's era cw transmitter

Another popular (but tricky) circuit from the 1930s was the LINK COUPLED RF 
final.

I had trouble with link coupling a few of times... Not everyone does. Your 
mileage will vary.
However, I had an ELDICO TV75-TVI model transmitter (or something similar) - 
and it was
great fun but would  only make a few watts out from the 807 P.A. until I 
converted the plate
circuit  from link coupling to a PI NETWORK (the easiest) and after that it 
greatly increased
the  ability to match antennas and produced 25 or 30 watts as best as I 
remember.

73 - Bry AF4K

On 2 Jun 2013 at 0:04, Richard Knoppow wrote:


>      Have a look at the ARRL Radio Amateur's Handbooks for
> the period. They had many low power transmitters.  Another
> source is the _Radio Handbook_ published on the West coast
> by Radio magazine, the predecessor to CQ. While it covers
> similar material to the ARRL handbook the approach is
> different and one can find many interesting projects in it.
> I think at least some ARRL handbooks may be available on the
> web.  I would look at somewhat later ones too, at least to
> the early 1950s because the tubes and other components may
> be easier to find.
>      It was quite common to have separate amplifiers and
> modulators as a matter of economy; that is a lot of hams
> could not afford to build a complete transmitter at once so
> built the amplifier for CW and later added a modulator.
>      There are many tubes capable of 50 watts either singly
> or by using two in parallel or push-pull.  Despite what has
> been said in other posts to this thread there are many plans
> for push-pull amplifiers shown.
>      The RCA Transmitting Tube Handbook, published in many
> editions over the years also has circuits for both
> amplifiers and modulators but does not give the mechanical
> plans as the handbooks do.  The RCA books have a very good
> tutorial on tubes and design and are worth reading.  At
> least a couple of the TT manuals are on the web.
>      I think this is an interesting project and should be
> fun.  The HRO is a good receiver and even the old ones
> perform quite well.
>
>      See http://www.tubebooks.org for a wonderful collection
> of scanned books on tube electronics.  Also, if you are an
> ARRL member you can get copies of articles from all issued
> of QST ever published except for some of the most recent
> ones from the ARRL web site.
>      Good luck with this.
>
>
> --
> Richard Knoppow
> Los Angeles
> WB6KBL
> dickburk at ix.netcom.com
>
> ----- Original Message ----- 
> From: "w5sum" <w5sum at comcast.net>
> To: <boatanchors at mailman.qth.net>
> Sent: Saturday, June 01, 2013 12:54 PM
> Subject: [Boatanchors] 1930's era cw transmitter
>
>
> > howdy y'all
> > I'm awaiting the arrival of my HRO Senior.  I want to
> > build up a 1930's era CW transmitter.  This could be a
> > cool thread.
> >
> > How many of you have built one and what did you use? What
> > tubes would you suggest?  I would like to have 50 watts
> > minimum output, but higher power is great.
> >
> > Yes, eventually I will modulate it.
> >
> > Suggestions?
> >
> > Ronnie W5SUM
>
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