Posted by
k6dgw on
Jan 10, 2018; 5:05am
URL: http://elecraft.85.s1.nabble.com/PAR-LNR-EFHW-antenna-tp7637237p7637291.html
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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