As the 406's are designed specifically to transmit to the SARSAT system, they
typically are larger 
due to their required signal strength, and the added complexity of transmitting
hex code signals.  
It seems unlikely that there would be available a compact 406 unit for this
application.  The 
compact 121.5/243 units that may be suitable for this application have, as you
pointed out, a 
limited range, and are effective only in alerting local resources if not picked
up by a satellite.  
Interesting to note that many SAR aircraft are equipped to detect the presence
of a 121.5 signal 
but not to DF it.  CG radio stations and ships are equipped to DF this signal
as well as VHF 
channels and other frequencies, but the equipment used is not within the price
range of most 
boaters.  I am aware of at least one production VHF/RDF combination unit
(Apelco?), but I don't 
know if it will DF 121.5.  Incidentally, there is one other type of emergency
transmitter used by 
vessels which transmits on VHF channels 16 and 15 (alternating; 16 for
alerting, 15 for homing).  
It is used primarily for inshore waters and is not compatible with the SARSAT
system.

Hope this helps.

-Sean


On Thu, 5 Feb 1998 01:17:40 -0500, Tom Mercier wrote:

>Sean, thanks appreciate the information.  A couple of questions...the 121
>EPIRB at the surface would have little range other than to aircraft where
>the line of sight might have a better angle to reach those aircraft or
>ships .  But wouldn't the 406 EPIRB work well at the surface as it is
>broadcasting to satellites which are higher in the sky and have a broader
>range of reception due to there being several in the visual sky?  Do you
>know of EPIRB's that are waterproof at depth and/or of a 406 that is within
>a reasonable price range for divers?  I have a 121/243 aboard my dive
>charter boat but it is not something that could be taken by a diver to
>depth without flooding out. Also do you know of a source for a RDF that
>could pick up both VHF radio and EPIRB signals in a compact unit at a
>reasonable price?
>
>Captain Tom Mercier 
>USCG Licensed Master
>Diver Medical Technician-ADV
>Nationally Registered Paramedic
>All Seasons Diving Company
>Dryden Michigan

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