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<font face="Verdana">So I've been wrestling with a new EFHW antenna
here and I have some questions/challenges/learning opportunities.<br>
<br>
I'm basing the build on the design described here:
<a class="moz-txt-link-freetext" href="https://batteryeliminatorstore.com/blogs/ocf-masters-articles/a-deep-dive-into-end-fed-half-wave-antennas">https://batteryeliminatorstore.com/blogs/ocf-masters-articles/a-deep-dive-into-end-fed-half-wave-antennas</a>
. After reviewing it again I can see that I need to do some work
on my 36:1 balun; my primary windings are too far apart. With
some trimming (folding back) I can get a decent match on 80 &
40 and sometimes 10, but the rest are > 2.5:1 SWR. I've tried
both wire and coax counterpoise - the results are basically the
same.<br>
<br>
Beyond that, I've observed that the noise level on the EFHW (I've
tired both the 80 & 40m multiband versions) is far higher (4-6
S units higher ) than on my 40+20m fan dipole. Overall received
signal strength is approx. the same although with the higher noise
level the copy is much easier on the dipole; weaker signals just
disappear into the noise on the EF where they are quite copyable
on the dipole. The EF is at about 20ft AGL and the dipole at
about 10ft. My expectation was that the EF, being longer and
higher, would have better S/N but I am experiencing the exact
opposite. Both are fed with LMR400; the dipole with 50ft, the EF
with 75ft.<br>
<br>
So my questions are basically these:<br>
<br>
- Do EFHW antennas have greater noise sensitivity compared to a
dipole? I don't really think this is the case, but it's a place
to start to determine cause.<br>
<br>
- When using a coax counterpoise, should the non-driven side
(counterpoise) of the secondary be shorted to the ground of the
coax (shield side of the primary)? I think yes, but I'd like to
confirm that. Also, that when using a wire counterpoise it should
NOT be shorted to the coax shield, correct?<br>
<br>
Thanks & 73,<br>
<br>
Tim - KC1RET<br>
</font>
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<h3>Tim Carter - KC1RET</h3>
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