[AMRadio] Plate modulating a 807

Brett Gazdzinski brett.gazdzinski at mci.com
Wed Apr 7 07:40:12 EDT 2004

Best thing to do is insert a choke in the screen circuit.

A small choke, 15 henrys or more will work.
Otherwise, you have to run the screen off a voltage divider,
some from the unmodulated B+, and some from the modulated B+.

The choke setup MAY hose you up on cw if you run cw, so a switch
or some quick way to remove the choke might be needed.


> -----Original Message-----
> From: amradio-admin at mailman.qth.net
> [mailto:amradio-admin at mailman.qth.net]On Behalf Of RJ Mattson
> Sent: Tuesday, April 06, 2004 11:19 PM
> To: amradio at mailman.qth.net
> Subject: [AMRadio] Plate modulating a 807
> This url is to my Hammarlund Four20 AM transmitter schematic.
> http://www.hvinet.com/rjmattson/four20schematic
> The PA 807 screen does not seem to be modulated through a dropping
> resistor or self modulated with a choke. The Hammarlund Four11
> plate modulator is connected in place of jumper MOD on the
> schematic. Should I try it as is or rewire?
> bob...w2ami
> www.qrz.com/callsign/w2ami
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