a64-
"I'm not abdicating trying to transmit on 243.0, just saying that while the military radio monitored guard freq automatically,"
I expect that military aviation radios do that for the same reason that military vehilces have 12V
electrical systems. Someone decided a long time ago (in the 1940's) that this would be a good idea and wrote a procurement regulation saying "We're not gonna buy it unless it has a 12v
electrical system" and in the same way, someone decided a common guard channel would be a good idea--and then simply wrote a procurement spec that said "We're not gonna buy it unless..."
That's all it takes. Clever, really.
" I know of no such civilian radio that does."
Well of course not. Civilians are a herd of cats, there's no one to write procurement regs for them. However, many
marine VHFs have the capability to automatically dual- or tri-monitor multiple channels at the same time, and 16 is usually a one-touch setup for those. Not 121.5, because that's still an aviation channel.
"I don't know of anyone that leaves a radio set to 121.5, that means you have one less radio to use."
You are kidding me, right? What, you retired when crystal-bound radios were still the standard? These days, radios are digital and monitoring two or ten or scanning a hundred channels pretty much in a second or two, is normal. Ham radio,
marine VHF, ICOMs and other that do air bands...my ham h/t will scan all the tower and ground frequencies for an
airport, and 121.5, and run through them all in a second or two.
No one dedicates a whole radio to one frequency, unless it is a rich or obsolete military
installation. Yeah, I know, B52s and missile silos are still using 1960's technology...that's not the real world.
"Most Airliners crossing oceans will leave a radio set to 123.45 " Rich owners with obsolete
equipment.(G)
"If your trying to get an Airliner on a
remote chance you have an aircraft handheld VHF, you'll have far more luck with 123.45 than 121.50" And the wonderful thing is, I don't have to dedicate a radio to it, or buy crystals for it. Just change the channel.
"But would the Coast Guard responding to an
EPIRB, be monitoring 121.5, and Aviation only
emergency freq?" Apparently, from published reports, all SAR air responders do. The reason that EPIRBs are mandated to broadcast a 121.5 signal, is so that approaching aircraft can d/f on the 121.5 signal. RDF is still a more certain way to find something, than "well we got these numbers from some guys who got these numbers from some guy who..." and with fond memories of
LORAN C and timing skip, numbers can be worthless compared to a needle[sic] that says "THAT WAY".