Have been on the hunt for one of these for some time, and was pleased to turn one up at a hamfest this week.

CM-1 by Jim QRB, on Flickr

Morrow CM-1 Conelrad monitor from perhaps 1953 or 1954. It's perched atop my 1956 Collins 75A-4. I did a really minimal restoration, simply replacing the electrolytic filter cap and two others I thought were paper, but after cutting them out, I suspect they were tubular ceramic and perfectly fine.

It was in pieces when I bought it, but looked pretty sound. Missing one original knob, but I had an aluminum knob in the "junque" box which is a passable replacement. It was also missing one tube, and as luck would have it, the gent I bought it from gave me a box of tubes, and low and behold, there was the needed 6C4 right on top o' the pile! What a fine fellow!

CM-12 by Jim QRB, on Flickr

As some may not know, Conelrad (Control of Electromagnetic Radiation), was a mid-1950's program designed both for emergency information distribution to the public and as a means of denying navigation and targeting info for Soviet bombers. The idea was that if an airborne attack was detected, all radio stations would be required to cease transmitting except designated emergency stations at 640 and 1240 AM, and those would be "shuffled" periodically so that they couldn't be used for navigation. Every commercial and amateur radio station was required to monitor a local broadcast frequency. If the station went off the air unexpectedly, a device like this would sound an alarm. You would check for other local broadcast stations (other than at 640 and 1240), and if they were also off, you knew to shut down your transmissions. There were a handful of commercial alarms offered and the hobby magazines of the day featured plans for the average ham to build a monitor which would meet the requirement.

Don't really know why this Cold War stuff fascinates me - just nostalgia from living through the "duck and cover" era I suppose. Regardless, it actually sounds quite good, and is a nice companion to my Civil Defense Gonset Communicator equipment.

Addiction by Jim QRB, on Flickr

Cheers... Jim

Nice!

Someday I’m going to buy me a gonset.

gcw said: "Someday I’m going to buy me a gonset."

They are a hoot, but heaven help you if you actually want to find anyone to talk with, unless you've got a buddy close enough to arrange a "sked." I've called CQ on 146.520 many, many times, but if anyone can pick it out, they either don't have an AM capable rig or any interest in pursuing it. I've even posted a note on the board at the local HRO (and I live near a pretty big city), but no takers for arranging an AM QSO. Too bad...

Wow!  Nice score.  Looks like you did very well.

146.52 is an FM simplex calling frequency and I strongly doubt the quadrature detector would pass AM. Seriously, try144.200 MHz, the SSB calling frequency. If there is an AM calling frequency I am not aware of it.
73,
Rob

Yes, roger that. It's just the only simplex frequency in the area where there is even occasional traffic. I have transmitted on AM and listened on an FM HT. It's readable, but not without a smidgen of effort or interest. It's much like the few times I've stumbled upon SSB on the 2-meter band. You have to have the interest (and equipment capability) to hunt down the mode of transmission. I don't have a crystal that will give me 144.2, but I do have the very rare Gonset VFO for the Communicator II. I just don't have it out yet - but will soon!

That's a fancy monitor. Most folks I knew either got a Heathkit or built their own and connected it to a scrounged radio.

Conelrad receiver is very cool.  I'll keep my eye out for one.

But, I am super jealous of the CD Gonsets.  I keep trying to snag one, but every one I see goes for $$$  It would go great with my huge collection of other CD "junk"

Haha! Why do we like that Civil Defense stuff - kooky, isn't it? I have decided that I much prefer the Communicator II with the "eye" tube, so that Comm III will have to go. It took a great deal of work, but that one is receiving very well and nicely aligned, but it doesn't want to go into transmit. Will sort that out pretty soon, but I have gotten distracted working on some old Central Electronics gear. I have been on the hunt for a G-28 in CD trim, but those are REALLY scarce. I've even wondered about buying and restoring a conventional G-28, and then going to the trouble and expense of painting it and having the front panel properly lettered. Of course after all of that, I'd have yet another radio I couldn't talk to anyone on, especially during our current propagation conditions! What a nut I am!

GonsetG28-W6YEP photo by Jim QRB, on Flickr