[AMRadio] Home Brew


George Pritchard gpritchard at comtechpst.com
Wed Sep 29 08:59:29 EDT 2004


Joe,
If you are going to cathode modulate that 4X1... Consider PDM Digital. You
will need twice the plate voltage +20% if you want 120% positive peak audio
capability. The 4-125 is the only tube in your list that can possibly hold
off the voltage and it's close at that.

FYI: I am finishing up a Class-D 4-1000 PDM modulator for my 4-1000 Class C
stage. It's a series modulator that will feed the 4-1000 class C plate and
is unique, with a floating cathode pulsed at 110KHz at 7KV. I call it
"high-side-PDM". This way a conventional RF deck can be PLATE MODULATED. The
grid switcher uses FETS, and the screen supply also floats at the 7KV level.
Optical coupling is used to get the PDM stream to the grid fets. If you are
interested in such a crazy project, let me know. It will be nice to have
digital audio from the class C 4X1 on 80-10 Meters... If it works and I
survive the testing process (scared). The rig will be called "4X1X4X1"
George AB2KC.

-----Original Message-----
From: amradio-bounces at mailman.qth.net
[mailto:amradio-bounces at mailman.qth.net] On Behalf Of Crawfish
Sent: Tuesday, September 28, 2004 11:19 PM
To: Discussion of AM Radio
Subject: Re: [AMRadio] Home Brew


I am trying to figure out how to cathode modulate the 4-1000 I have. I have
a pair of 813's and have a 4-125. Have a bunch of 807's and 1625's as well.

Joe W4AAB
----- Original Message -----
From: <W4AWM at aol.com>
To: <amradio at mailman.qth.net>
Sent: Tuesday, September 28, 2004 6:47 PM
Subject: Re: [AMRadio] Home Brew


> There are all kinds of good designs in the 50's handbooks. The most 
> fun
you
> will have is trying to find all the parts.
>
> 73,
>
>   John,  W4AWM
>
> << I'd like to build my own AM transmitter. Tube style; more than 200
watts. >
> >
> ______________________________________________________________
> AMRadio mailing list
> Home: http://mailman.qth.net/mailman/listinfo/amradio
> Help: http://mailman.qth.net/mmfaq.html
> Post: mailto:AMRadio at mailman.qth.net
>


______________________________________________________________
AMRadio mailing list
Home: http://mailman.qth.net/mailman/listinfo/amradio
Help: http://mailman.qth.net/mmfaq.html
Post: mailto:AMRadio at mailman.qth.net




More information about the AMRadio mailing list

This page last updated 23 Oct 2017.