David VanHorn wrote:

>>>If we ran a wire from the transmitter antenna through an air line that
>>>has to go to the underwater unit and connected it to the receiver
>>>antenna, would that work?
> 
> 
> You'd actually have to attenuate the signal significantly, and it
> would be best to use shielded cable, but YES, this will work.

Actually, it would depend on the kind of water (fresh vs salt),
and on the radio frequency in use.
Salt water, and high frequency (2.4Ghz is now used in many sets)
and you won't get far, even with a wire. I doubt that you can do
300M even at 72Mhz (common R/C band in the US) with just a bare wire.
The loading from salt water is HUGE.

I would suggest using COAX so that you have a controlled impedance path
to the receiver, and then yes, it will work. But I agree that you will
probably need an antenuator to not overload the RX.
If you need it thin, RG174 coax is about 1/8" diameter and not too lossy
at 72Mhz.

Robert

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