David VanHorn wrote:
>>  You should NOT read:
>> http://www.halfbakery.com/idea/Voice_20of_20GOD_20on_20the_20road and
> 
> 
> Two words.. COMB GENERATOR.   Who CARES what channel he's listening to?

Been there, done that, got the t-shirt. AM, FM, emergency services.

Unfortunately, the ones I worked on were not mobile.  They were inside 
highway tunnels.  Cars went in, their radios went dead, drivers complained.

Guy I worked for 20 very odd years ago built these systems.  One or two 
were installed in Hawaii, a few in California, and one in the I-95 "Ft. 
McHenry" tunnel in Baltimore. Others in other tunnels.

An outside antenna picked up the AM-FM bands and an amplifier 
rebroadcast them in the tunnel along Radiax strung along the walls on 
standoffs.  In the event of trouble, the tunnel operators could switch 
off the re-broadcast and turn on a comb generator and put their 
emergency messages on all station slots simultaneously. Police, fire and 
ambulance services were also accommodated.

A digital voice recorder had canned messages like "the tunnels on fire 
and you're all going to die!!!"  I think they removed those.  No sense 
of humor.


-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist