[AMRadio] Re: AM Transmitter Advice??


Brian Carling bcarling at cfl.rr.com
Fri Feb 17 05:30:46 EST 2006


I think that was the APRIL issue of Tube Collector magazine.
The heck of it is, he used a galena crystal as a modulation 
transformer!

On 16 Feb 2006 at 20:42, John Coleman ARS WA5BXO wrote:

> OK BOB!
> 	You got my attention. Explain more.  I hope I'm not a sucker
> here.  I have seen and extremely low mu amplifier circuit (common
> cathode) made by reverse biasing the plate of a triode and forward
> biasing the grid where output is taken from the grid and input is on the
> plate.  So I know that weird stuff does exist.
> 
> John, WA5BXO
>  
> 
> -----Original Message-----
> From: amradio-bounces at mailman.qth.net
> [mailto:amradio-bounces at mailman.qth.net] On Behalf Of Bob Deuel
> Sent: Thursday, February 16, 2006 6:05 PM
> To: 'Discussion of AM Radio'
> Subject: [AMRadio] Re: AM Transmitter Advice??
> 
> Hello Larry and all:
> 
> Larry's tongue in cheek comment employing 866's as a linear amplifier
> tube
> prompted me to contribute the following: Certain full-wave rectifiers
> can be
> configured to amplify or oscillate. I have built audio, Hartley and
> Simpson
> oscillators using only 6AX5GT's full-wave rectifiers as the sole active
> device. These were displayed at 2004 Mid-Atlantic Antique Radio Club
> Meet
> and actually won a Blue Ribbon.
> Late last year I built an AM transmitter consisting of a Hartley
> oscillator
> modulated by an AM modulator using only 6AX5GT full-wave rectifier tubes
> as
> the active devices. No solid-state magic, just simple full-wave
> rectifiers.
> The basic concept is that of the Heintz and Kaufman gridless Gammatron
> circuits. The transmitter was set up for the broadcast band and works
> fine.
> It has been publicly demonstrated a couple times now and a write up
> including the circuit was published in the February, 2006 issue of the
> "Tube
> Collector" magazine which is the bi-monthly magazine published by the
> Tube
> Collectors Association, Inc. It is fun to make full-wave rectifiers do
> more
> than just rectify.
> 
> Bob, K2GLO   
> 
> -----Original Message-----
> From: amradio-bounces at mailman.qth.net
> [mailto:amradio-bounces at mailman.qth.net] On Behalf Of ne1s
> Sent: Thursday, February 16, 2006 10:36 AM
> To: Discussion of AM Radio
> Subject: [AMRadio] Re: AM Transmitter Advice??
> 
> Donald Chester writes: 
> 
> > 
> >> Assuming one is going to build a linear, and so putting aside other 
> >> issues
> >> such as linear vs plate modulation, why do you think it makes a 
> >> difference
> >> what tube is used? Are you referring to running a linear at greater
> than
> >> legal limit?.
> > 
> > Well, go ahead and try building a legal limit linear that runs a pair
> of 
> > 807's in the final. 
> > 
> 
> Yeah, or a pair of 866As.... 
> 
> Sorry (the devil made me do it). 
> 
> 73,
>  -Larry/NE1S
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