[AMRadio] Modulator for DX60 available

W5OMR/Geoff w5omr at satx.rr.com
Fri Apr 14 12:22:55 EDT 2006

Rev. Don Sanders wrote:

>Geoff, while you may not have seen it, 
>WRL made a screen modulator for a 
>couple of their CW only small transmitters 
>back in the 60's that was external to the 
>transmitter and plugged into an accessory 
>socket on the back of the transmitter. 
>Rather rare now.   
>BTW, I have copy of 2 articles for a 
>Bias-shift modulator from the 50's and 
>how to apply it to a DX60 for high 
>level plate modulation. It uses a 
>modulation choke for a form of 
>Heising modulation and used the 
>built in controlle modulator to drive 
>the modulator tube- usually the same 
>type as the final tube./ I recently 
>found a 6 henry 200 mil choke and 
>I am going to try it on my DX60B.
>Healthfully yours,
>                          DON W4BWS

Just because I havn't seen it, doesn't mean it doesn't exist, Don :-)

Sounds interesting, though.  I wonder how that would work out, with 
something a bit larger?  Say, a 250 or 300w dissapation tube in the 
final, and one of the same in the bias-shift modulator?

You might need a choke that would handle more than 200mA, but 10HY 
chokes @ 500mA seem to be plentiful.  I've got a half-dozen or so, here.

Homebrewing at it's finest.  You could probably even get away with using 
a common DC supply for modulator and final, in that configuration.

73 = Best Regards,

A: Yes.

> Q: Are you sure?

>> A: Because it reverses the logical flow of conversation.

>>> Q: Why is top posting annoying in email?

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