[MHml] ARC

[Glenn Brown]

>> The idea of an allert through VHF came up. (YV) radio can be set at a very 
>> loud level but squelched so it is inaudible on 'standby' The trick is to 
>> have the other vessel call you when they are within VHF range .... well ..

Tell your DSC equipped VHF to call All Ships with a priority of 
"Safety".  This way, at least the US commercial vessels will be required 
to respond (as they all must have DSC VHFs, and must respond to the 
safety call).

I expect the average power required for DSC hailing in 1 Watt transmit 
mode should be on the order of 0.1 Watts, which would drain a 12V 80 
Amp-Hour marine battery in about 400 days.  YMMV.

> might not have a loud audible alarm.

Find a HAM (amateur radio operator) in your area and ask them who the 
local radio tinkering guru is.  Then get the guru to open the radio, tap 
into the signal to the (probably piezoelectric) alarm, and adapt it to a 
much louder alarm.  This is about as simple a radio hack as there is.

The guru might just be able to help you with the auto-hail on VHF 16 
system, as this is the sort of thing HAMs just love to do.

Finding HAMs worldwide is easy: use the directory at 
http://www.qrz.com/callsign .

--Glenn