Ahhh yes, the End-fed Zepp. Trailing wire out the back of the gasbag,
open wire line to the TX with one end open at the antenna. Every time
someone mentions it, I have Hindenburg dreams.
Yes, it does need a small something for a counterpoise, given the small
current in the high impedance load. One model I tried on 20m needed
about 17 cm of counterpoise, but those little currents seem to use
whatever is available and apparently, there's always something
moderately conductive available.
Sometimes, I think we forget that we are "Amateur" radio operators.
We're not designing antennas for a broadcast station or the VOA.
73,
Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County
On 1/9/2018 5:48 PM, K9MA wrote:
On 1/9/2018 19:25, Bill Johnson wrote:
With a 1/2 wave a counterpoise is not used.
It needs SOME counterpoise, but not much, because the current in it is
very small. If nothing else is available, the coax shield will
suffice, and causes no harm. The small current at the end of the
antenna has to have a return somewhere. I recall old versions of the
Handbook showed an EFHW fed with open wire, with nothing at all
connected to the other conductor, and never could figure out how that
worked. I suppose a little common mode current in the open wire
line. Later versions, I think, showed a short wire opposite the
antenna, which at least made sense to me. The point is that the very
small current at the end of the EFHW will find a return somewhere, and
it really doesn't matter.
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