Hello-
Just a note here - I have been going through my shop and re-organizing
things, have several sets of transformers { from audio input to modulation
transformer } that would probably work well for building up plate modulator for
smaller rigs that need to be converted to plate modulation.
These transformer sets were removed from FAA transmitters and are quality
sealed types. The modulator setup was to plate modulate a 4X150 type tetrode {
mod. trans. have plate and screen winding} using pair of 6146 modulator tubes
in push/pull. The lower level speech amp stages have a couple of other
transformers involved. Mod. trans. rated for 65 watts.
I have technical data on all transformers and schematic of original
modulator circuit that I can send along with them.The transformer sets weigh
about 30 # total which would not be too bad on shipping.
Anyway, trying to thin down on items I have excess of. Will sell set for
50.00 plus shipping.
Thanks, Byron.
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Date: Fri, 14 Apr 2006 11:22:55 -0500
From: W5OMR/Geoff <[EMAIL PROTECTED]>
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To: Discussion of AM Radio <[email protected]>
Subject: Re: [AMRadio] Modulator for DX60 available
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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,
-Geoff/W5OMR
A: Yes.
> Q: Are you sure?
>> A: Because it reverses the logical flow of conversation.
>>> Q: Why is top posting annoying in email?
