[Milsurplus] Re: SCR-274-N Transmitter Dial (really Etc.)

[J Forster]

I don't think the effect is capacitive. Consider you have a rectangular
volume with fairly well conducting walls, a few to a few tens of
wavelengths in every direction. It looks sort of like a cavity at HF.
The Q will likely not be high, but there will be resonances. The wire
antenna is like an E field probe that couples to the cavity quite
strongly. Because the walls will, in general, not be an integral number
of half wavelengths apart at the same frequency, there will likely be
three separate sets of resonances (X, Y, and Z).

This would make tuning very tricky at best.

FWIW,
-John

==============


Hue Miller wrote:

> I'm sure those considerations are valid. A 15-20 foot wire when
> operated in the
> range of 3 MHz will develop substantial voltage. I'm sure many of us
> got white
> spots on our fingers verifying this.
> However, on a single place plane or plane with no radio op, you have
> to maximize
> the antenna current and leave it at that. Below decks on a flattop in
> the repair area
> or such, you can imagine the capacitive effect would be much more than
> in an aircraft
> hangar, at least the usual fixed-base hangar. [snip]