[MRCA] WS-19 Modulation

[J Mcvey]

 The modulation killer on the WWII radios is often the carbon microphone. They are supposed to be 50 to 100 ohms, but often read several hundred ohms or even into the K ohms!You're not going to get much power into the modulator with a high resistance mic.
I had to make a couple of different circuits using electret mics to bring the modulation up to snuff.
    On Monday, June 9, 2025 at 11:51:36 AM EDT, Mike Feher <n4fs at eozinc.com> wrote:  
 
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Hi Ray – 

  

I used a 19 set on the military nets on 75 on occasion. This was in the later 80’s. I also always used it with the original dynamotor power supply box. I typically used a T-368F for rag-chews and when I was net control. I found the original set to have more than adequate modulation. My set was mint with all the accessories. I still have it down in the basement. I also made a Pye to BNC adaptor to make it interface easier with my antenna switching and power meter, etc... 73 – Mike 

  

Mike B. Feher, N4FS

89 Arnold Blvd.

Howell NJ 07731

908-902-3831

  

From: mrca-bounces at mailman.qth.net <mrca-bounces at mailman.qth.net> On Behalf Of Ray Fantini via MRCA
Sent: Monday, June 9, 2025 10:03 AM
To: MMRCG at groups.io; mrca at mailman.qth.net
Cc: milsurplus at mailman.qth.net
Subject: [MRCA] WS-19 Modulation

  

Picked up a WS-19 at Hamvention, it’s a basket case so have no problems doing some modifications to it. Started by removing the VHF set and am now in the process of replacing tons of capacitors and lots of the old brittle wiring.

The goal is to end up with a another low power AM transceiver that I can run at events.

In addition to the VHF junk that's been removed they also had an intercom audio amplifier in the set and have been thinking of using that to drive a speaker or better yet as a modulator for the 807 in the PA. The existing circuit uses a grid modulation system but wondering if anyone ever used the 6V6 in the intercom amplifier to modulate the 807 as a plate modulated transmitter? figure maybe I can find an old tube CB that I can take the modulation transformer out of.

  

Ray F/KA3EKH

  


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