Bruce in Alaska wrote:
In article ,
Dave wrote:


On Wed, 25 Jan 2006 07:05:34 -0500, Larry said:


If they
have any DSC at all, it's transmit-only just like yours.

Perhaps you could explain the following from the manual for one of the
common VHF units:

"Receiving an All Ships Call
If you are currently on a selected working channel or private channel, in
the Monitor mode, or in the Scan mode, the radio automatically enters
DSC mode when an All Ships Call is received. The type of call is displayed
in the small channel display and an alarm is sounded.

Press the DSC/PRI key once and the radio automatically selects channel
16. There is no acknowledge required for an All Ships Call. If you do not
wish to accept the call, press the 16 key to exit the DSC mode."


Yep, the above IS correct. However, look at what it really says.....
"IF" you are in the "Monitor Mode", or the "SCAN Mode" then your radio
will respond to a DSC Call, but only IF it isn't already receiving on
another channel, AND the DSC Call lasts long enough for the scan rate of
the receiver to get to Ch 70, and decode a complete DSC Sentance....
otherwise you don't get any indication that a DSC Call was ever received.
Are you willing to BET your LIFE, that other boaters IN your area,
understand how to correctly operate their DSC equiped radio, AND
will respond to your call? This IS Exactly Why, the 406 EPIRB is
required equipment on any FVSA Compulsury Required Vessels AND any
SOLAS Required Vessels, and is the PRIMARY Distress Notification
Device aboard. It WORKS, and has a Proven SAR Track Record.

Bruce in alaska
When you compare VHF radios with EPIRBs you are comparing apples and
oranges. VHF radios are for short range comms including distress and
calling. (even the DSC ones) EPIRB are locator beacons used to help
find the beacon (hopefully associated with an emergency) EPIRBs are not
designed to be tossed over the side willy nilly for fire and flood or
what ever. They won't let the guy two miles off your starboard quarter
know you have a problem. VHF will.

Gaz