[MRCA] Was BC-611 now short antennas and Sky Diving

[Tim]

Hi Ray - BC-611/Parachute mobile has been attempted fairly recently.  Mark
AF6IM and friends do parachute mobile during the Pacificon event out this
way, most years.  I have worked them on 2 meters FM and also 20 meters USB
while he was descending airborne from 14K feet.  20 mile path obviously no
problem.
He did try a BC-611 several years ago but apparently No Joy.  I was using a
GRC-9 from Mt Diablo which would have been an optical LOS path but I did
not hear him over that 15 mile path.  I recall he reported hearing me.
A guy in Menlo Park (?) says he heard him but I am very surprised that he
did over that 45 mile path, but I did not...  But it was cool to try - I
was surprised that I could not hear him at my end..Even with the extremely
poor radiation efficiency of that set.

Tactical combat use of a BC-611 while descending?  I doubt it was even
tried (for what purpose? - especially for presumably low altitude
jumping..)  Who knows, but an interesting thought experiment.
Tim
N6CC


On Sat, Oct 5, 2024 at 12:02 PM Ray Fantini via MRCA <mrca at mailman.qth.net>
wrote:

> Question for smart people, you would think I know this but as my wife will
> often remind me that I am not the sharpest tool in the shed. I think a half
> wavelength at 3885 is a hundred twenty feet or so, assume the 611 has a
> huge coil to make up for this short antenna? Mr. Smith once told me that
> although you can electrically shorten the active side of a antenna with a
> coil that dose nothing for your other side of the antenna, the counterpoise
> and for that to be most effective it’s got to be some sort of fraction of a
> wavelength. Dam, the counterpoise of the BC-611 is like one foot of case!
> Maybe there is some component of grounding thru your skin and boots or
> whatever but what if you’re wearing gloves? This is where the smart part
> comes in, I am assuming the efficiency of that short antenna and
> counterpoise results in an overall antenna efficiency of about lest then
> five percent! Certain some smart person out there can run the program and
> come back with an exact number.
> Think about this in the context of parachuting, even if the antenna was
> fully extended the ground or counterpoise side of the antenna is like one
> foot if you were wearing gloves, I don’t think polarization or any of that
> stuff matters with that small antenna and radio.
> My real question is how in the hell did you free fall , deploy the chute
> and all that other sky diving stuff and hold on to the radio in the first
> place? That’s an impressive feet.
> Trivia! Two radios I have always like from WW2 are the DAV and its evil
> twin sister the MAB, don’t know if its true but I was told the MAB was
> designed and deployed as an air assault radio. It used a throat microphone
> and a weird skull cap that fit under a helmet with the radio strapping to
> your chest.
>
> Ray F/KA3EKH
>
>
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