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[aprssig] "Emergency!" test convention?

WB4GQK at aol.com WB4GQK at aol.com
Thu Jul 22 19:16:52 UTC 2004


Seems to me emergency testing from APRS stations could be handled in much the 
same way that emergency testing of Marine DSC, GMDSS, and EPIRBS are handled 
not only with the USCG but with all nations who are participants in the 
International Marine Union, I.M.U.

In very simple terms the basic concept is you direct your emergency test to a 
specific coast station that is available within your HF or VHF radio range. 
In other words you do not transmit a MAYDAY "to whom all can hear me" but 
rather to a specific station. Directing the test to a specific station tells 
everyone that it was a "PLANNED" test.

I have tested my own VHF DSC emergency transmission to the local USCG station 
a number of times. Each time I received an answer that simply read "MMSI 
338023228 (my boat's Marine identification) emergency message and position 
received correctly" Of course there is no standard time or day setup for these tests.

On the other hand emergency testing of HF DSC has turned out to be very 
controversial! This is primarily caused by the limited number of DSC channels 
available on HF world wide and the high traffic presently caused by ship-to-ship 
and ship-to-shore calling plus the fact long range propagation causes a lot of 
interference.  

There are three of us who are members of a local Yacht Club and we tested our 
HF DSC by directing the "emergency test to each other's vessels" We were 
primarily interested in the transmission of our GPS position. Very obviously this 
required a lot of coordination between the 3 of us.

This is just a thought but emergency testing has been addressed in other 
operational fields, and it might be possible to utilize some of their techniques.

73 de Jim




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