[Lowfer] W5JGV E- Field Probe

[W5JGV (Ralph Hartwell)]

> I am going to duplicate your e-probe design. I am curious as
> to why you used 9 Ft. of #10 wire. is that number critical  to your
> design or is it what length you had on hand at the time?

Hello Tom,

<grin>  Well...  the answer is two fold.

First, the length of PVC pipe was actually 9 feet long, not 10 feet.  It
seems that I had "borrowed" a bit of it earlier on for another project.

And the second reason is that the length of connecting wire between the
bottom of the PVC antenna tube and the input to the amplifier was about
a foot or so long, making the total antenna length the desired 10 feet.

The length is not critical.  Obviously, a longer antenna wire gets you
more signal into the amplifier, but with the attendant chance of blowing
the FET during thunderstorms.  Plus, if the length is too long, signal
is lost at frequencies above 25 MHz due to wire resonance.  The original
AMRAD E-Probe antenna used an 18" antenna, IIRC.  And as for the wire
diameter, well, I used #10 just because I happened to have about 3000
feet of it on hand.

73,

Ralph   W5JGV - WD2XSH/7