At 2:58 PM -0500 10/7/02, Billy Cox wrote:
>I complained? :-P
You said "let's keep the models as close as possible," which sounded
to me like a complaint -- and a **fair** complaint -- that comparing
antennas of unequal lengths was unfair (even though I had described
completely and correctly what I had done).
To avoid unfairness, subsequently I compared antennas having equal lengths.
>I and others will now know to ignore your posts in the future on
>here. Like the one last week saying that insulation on wire made no
>difference....
I never said that insulation on wire made no difference. I did say
that the effect of insulation on an antenna wire is much smaller than
the effect in coax, i.e., much less than you'd expect from the
"velocity factor" usually cited for the dielectric material in
question; and I explained (AFAIK perfectly correctly) why this is so.
I also said that other factors, e.g.,proximity to ground and other
conductors/dielectrics, are typically more important.
FWIW, in his post today, K5RC seemed to say that his 160-m sloper of
jacketed #10 wire "wound up" having the same length as he'd computed
for bare wire, *not* what he'd computed assuming 95% V.F.
>BTW, using 7.5 degrees is probably a bit on the low side
>of the range for low band arrival angles ... but wait, you'll
>just say I complained about that too ... <sigh>
>
OK; I won't call that a "complaint." How 'bout if I call it a "suggestion"?
According to ICEPAC and VOACAP, 7.5 degrees is a typical arrival
angle at my QTH of an 80- or 40-m wave from the UK via the usual, 2F,
path.
Other paths have different arrival angles, some higher, some lower.
In my original post I offered to rerun NEC-4 for other angles,
frequencies, etc.
I'm not selling anything. I'm reporting what NEC-4 says. I am
interested to hear what others report. As always, YMMV.
73 de Chuck, W1HIS
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