[Hallicrafters] OK I give up !

[Kenneth G. Gordon]

On 24 Apr 2008 at 16:28, Richard J. Fiero II W5TFW wrote:

> what,.......... was the purpose of monitoring an am  STATION ?

For CONELRAD purposes: ALL AM stations were required 
to go off the air in the event of a nuclear attack so the 
enemy couldn't use an AM station to DF on, as the 
Japanese did at Pearl Harbor on Dec 7, 1941

SOME of the stronger stations, chosen for their signal 
strength and coverage, were required to switch to either 
640 Khz or 1240 Khz in a timed sequence with other strong 
AM stations so that the enemy could not DF any particular 
location via an AM station, since the directions would be 
switching to a different station in a different location every 
few minutes or seconds.

Of course, this meant the the signal strength of any 
640/1240 "station" you were monitoring could change 
drastically from one minute to the next.

All of these special "CONELRAD" stations were tied 
together so that they broadcast exactly the same material 
at exactly the same time, usually by the same person.

So, by monitoring a local AM station, most of which were 
NOT on either 640 or 1240 Khz, when your choice of AM 
station left the air unexpectedly, your ham transmitter would 
be automatically shutdown.

Simple, eh?

Ken Gordon W7EKB