[Boatanchors] Morrow CM-1 CONELRAD Radio

[Rodger Singley]

As Grant noted the CM-1 operates like other simple “CONELRAD” receivers of the time and as soon as the carrier is dropped the alarm goes off.  The full standard called for an off on off and then on  carrier sequence with a 1 Khz. tone sequence to trigger the receiver but a simple “carrier drop” detector alarm was sufficient to meet the requirement that every ham use such a monitor so that is the type you will commonly find since it was simple and cheap to construct.

As an added bonus, your CM-1 (like the Johnson electronic T/R switch) generates a lot of heat in a small box and doubles nicely as a coffee cup warmer.

Rodger WQ9E

Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10

From: GRANT YOUNGMAN<mailto:ghyoungman at gmail.com>
Sent: Tuesday, February 27, 2018 1:43 PM
To: Howie WA3MCK<mailto:wa3mck at gmail.com>
Cc: Boatanchor group<mailto:boatanchors at mailman.qth.net>
Subject: Re: [Boatanchors] Morrow CM-1 CONELRAD Radio

There’s nothing required to activate the relay than the station you are monitoring going off the air.  I suppose you can test by tuning to a station, and then disconnecting the antenna.

The idea was you tune to a strong non-Conelrad station.  If that station dropped carrier, the CM-1 alarm would sound.  You then had to tune to one of the two marked Conelrad frequencies (640/1240 KHz as I dimly remember), where actually emergency broadcasts would occur.


> On Feb 27, 2018, at 2:25 PM, Howie WA3MCK <wa3mck at gmail.com> wrote:
>
> Gang,
>
> My local radio group has procured a working Morrow CM-1 CONELRAD Receiver
> in pristine condition.
>
> How can we simulate a CONELRAD signal to activate the relay in the radio?
>
> Brand new relay installed with a good NOS 6C4.
>
> Howie WA3MCK
> ______________________________________________________________

______________________________________________________________
Boatanchors mailing list
Home: https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fmailman.qth.net%2Fmailman%2Flistinfo%2Fboatanchors&data=02%7C01%7C%7C17de2123080649a6436108d57e1a6945%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636553574250723563&sdata=8bxoIyDqhW9E9PlF8osNf06RpMwzRpZqEtsXpvysOhg%3D&reserved=0
Help: https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fmailman.qth.net%2Fmmfaq.htm&data=02%7C01%7C%7C17de2123080649a6436108d57e1a6945%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636553574250723563&sdata=LXoPQ%2BtVPNL6rM%2FTx6D1WkLbItH1WOBIbx0qVqwMBvg%3D&reserved=0
Post: mailto:Boatanchors at mailman.qth.net

List Administrator: Gary Harmon, K5JWK
** For Assistance: gharmon at idworld.net **


This list hosted by: https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.qsl.net&data=02%7C01%7C%7C17de2123080649a6436108d57e1a6945%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636553574250723563&sdata=x%2BkdJ3sF9I591hfArTdg3x5dfq6CXE2TQQeE1Jtpw0g%3D&reserved=0
Please help support this email list: https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.qsl.net%2Fdonate.html&data=02%7C01%7C%7C17de2123080649a6436108d57e1a6945%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636553574250723563&sdata=hAhLUwsOYRkIaYteeu8mWx8%2Fn%2BqyQf5g2lG82aCD6hc%3D&reserved=0