Reverse biasing the galena crystal was a stroke of genius. 100% negative
side modulation with no need for clipping on the pos. side. Cleanest
class C sine wave ever. Brilliant.
Brian Carling wrote:
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: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] 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: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] 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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Reverse biasing the galena was a stroke of genius
