[AMRadio] Amplifier to use with my DX-60

Mike Sawyer w3slk at uplink.net
Sat Mar 18 23:50:31 EST 2006

I would be interested in that Dennis.
----- Original Message ----- 
From: <W7QHO at aol.com>
To: <amradio at mailman.qth.net>
Sent: Saturday, March 18, 2006 11:07 PM
Subject: Re: [AMRadio] Amplifier to use with my DX-60

For a simple and very effective modulator for rigs in this power class that
doesn't require increasingly hard to find modulation iron, let me recommend 
Heising circuit originally described in the April 1955 issue of Radio and
Television News and revisited in ER #91, Nov. 1996. The scheme utilizes a 
bias shifting scheme to squeeze 30 - 40 watts of audio out of a single 807
modulator tube. No transformer required, only a 10 H filter choke. Won't
modulate 100% in the negative direction (in common with other Heising 
circuits) but
comes so close you can't tell the difference.

The original author called it a "Reference Shift Modulator." Can provide
more information if anyone's interested.

Dennis D. W7QHO
Glendale, CA
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