Multiple comments below:
WA3GIN:
>Great subjective opinions.
Subjective? Did you miss the
RESULTS in my original reply? ;-)
> I hold all USA records on 10m, both modes,
in CQ WW, ARRL DX and CQ WPX. Over 21 contests, my
system has consistently beaten the average of the
top 3 MM stations on 10m, so it indeed works.
http://users.vnet.net/btippett/new_page_6.htm
K1MK:
>The original comment was in the context of
using fixed direction Yagis in a stack.
54 degree BW easily covers all of
EU and most of AF and Middle East AS from
here (e g. 30-84 degrees).
>So its HFTA first to get the heights/spacings,
then back to NEC, YO, etc. to tweak the lengths
and spacings for that specific stack.
That's what I did. I found the F/R
using KLM dimensions was not very good in
the stack. I then modeled two antennas in
YO and got ~1 dB more gain, ~8 dB more F/R
and better SWR bandwidth from 28.0-28.8 MHz.
http://users.vnet.net/btippett/yagi_optimizer_7_0.htm
...but the *real* reason I did it was better F/R.
WC1M:
>I've done a fair amount of modeling for my 3-stack
of 4-el SteppIRs
I'm just curious how you model the tape
elements used in the SteppIR? I assume you set
and store the lengths of each elements once you
know what they should be.
K5GO:
>Let's say you could double the boomlength and realize
about 3 dB more of gain than the original antenna.
It's <2 dB...not 3 dB. My antennas are on
a 27.5 foot boom and ~10.7 dBi. The M2 is on a
44' boom and claims 10.25 dBd gain, which equals
12.35 dBi or 1.65 dB difference. I don't have
a 48 foot boom OWA model handy but I am positive
it would be <2 dB. The mechanical considerations
of going from 27.5' to 55' are not worthwhile in
my opinion. Check the results in my link above
versus other MMs using much larger systems...I don't
think you will find their much larger antennas
make a significant difference.
W6RMK:
>Especially when it comes to suppressing atmospheric noise (which is
very unevenly distributed) this might actually be more important than
raw gain (at least on receive). On transmit, of course, you want all
the gain you can get in the desired direction.
I agree. I would much rather have a very
clean forward pattern with very good F/R than
antennas with more gain. Receiving S/N is much
more important than forward gain, especially on
a band like 10m where even QRP signals are quite
readable.
Final comment. At least on 10 meters I
find the top antenna in my 3-stack to be of marginal
use. Most of the time the lower-2 are better than
the full stack. However the top is very useful
for spraying in a secondary direction. Most MMs
have other antennas for that purpose but I have
only the 18 el 3-stack. KC1XX for example has
>70 total 10m elements the last time I checked.
That's OK...I like a handicap! ;-)
73, Bill W4ZV
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