Moxon 40m to low, 6.8 kHz?
Try simulate with in calculated s.c. "Skin eff";
Look at Moxonantennaproject some of my 40m Mox files. For copper in PVC wire
need calculate resonance on 7.240 for 7.050 on mast in any program.
----- Original Message -----
From: antennaware-request@contesting.com
To: antennaware@contesting.com
Sent: Sunday, February 28, 2010 9:00 PM
Subject: Antennaware Digest, Vol 74, Issue 7
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Today's Topics:
1. Simulating the W6NL 40M moxon variant (knormoyle@surfnetusa.com)
2. Ideas on how to mount 6 M j-pole? (Shon Edwards)
----------------------------------------------------------------------
Message: 1
Date: Thu, 25 Feb 2010 13:51:59 -0800
From: "knormoyle@surfnetusa.com" <knormoyle@surfnetusa.com>
Subject: [Antennaware] Simulating the W6NL 40M moxon variant
To: antennaware@contesting.com
Message-ID:
<f208740f4c1f41d7918cfbc536cef498.knormoyle@surfnetusa.com>
Content-Type: text/plain; charset=utf-8
My problem: I'm working on a simulation for a M2 40M2L (shorty-forty, linear
loading) conversion to a moxon. I'm using the W6NL 40M moxon-like design as a
benchmark for SWR bw, and gain/fb. (trying to get similar results, but not
the
same design)
W6NL provided an AO .ant file so his can be easily simulated.
here:
http://www.kkn.net/dayton2004/
(3 links there)
I use 4nec2x, so I used it to convert the .ant to a .nec. There were some
minor
issues that I hand-corrected. (for instance, using ' in a symbol name in the
ant)
The simulation of the W6NL moxon looks good in 4nec2x. The visual is right
for
the antenna, the gain/fb and swr bandwidth is right (very wide swr bandwidth).
BUT: the swr min is centered too low I think..it's around 6.8Mhz..I would
have
expected it to be centered around 7.05 or 7.1, based on W6NL's presentation
curves.
I experimented a little. I played with different grounds. The simulation is
at
70 ft. The taper schedule is done with explicit wires of different radiuses,
but
it seems fine.
I'd be surprised if nec-2 is simulating this wrong, compared to AO...
So I'm assuming something is just wrong, but I can't figure out what.
It's like it's shifted down in frequency for some reason.
If there was someone out there would could run the .ANT file exactly as W6NL
posted it above, and say what freq they see for a SWR min, that would be
really
useful for me? I also could put my converted .nec somewhere if there was some
other simulator that could use the .nec? (or people can recommend something I
could use without retyping in a model?)
I'm a little worried, because I have the design for my 40M2L conversion done,
and I think it's pretty good (got the wide bw I wanted). nNot that much less
than the W6NL, but has just the typical moxon look (less aluminum) and on a
shorter boom (19-1/2') feet....But now I'm wondering if that simulation is
accurate..
I don't know if there are other simulators that could use the .nec, but I
could
provide that also (both the W6NL and mine) if anyone was interested in seeing
what they get for me.
thoughts?
thanks
kevin
AD6Z
------------------------------
Message: 2
Date: Sat, 27 Feb 2010 11:04:18 -0700
From: Shon Edwards <sre.1966@gmail.com>
Subject: [Antennaware] Ideas on how to mount 6 M j-pole?
To: antennaware@contesting.com
Message-ID:
<74b45fe11002271004j48a5afc1r33a9ccd760f831a5@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
Does anyone have any ideas on how to mount a j-pole on the edge of a roof,
which is for the 6-m band? It is absolutely huge (somewhere between 13 and
14 feet high, I believe). The wind seems to be able to move it around more
than I thought it would before getting the antenna.
Very nice antenna, though, for a j-pole (dipole), and with it on the ground
have been able to hit repeaters as far away as 50 miles with mountains
inbetween. (That knife-edge has always been wonderful to me. To digress a
moment, I was able once to talk with my wife on simplex 30 miles apart, with
each of us on opposite sides of a 11,000 foot high mountain, with full
quieting.)
Thanks in advance,
73 de Shon, KO3U
--
Shon R. Edwards,
Amateur Call: KO3U
Commercial radio licenses:
GROL: PG00016801
GMDSS/O/M: DB00000391
GMRS: WQKW341
2nd class radiotelephone: T2GB064388
Accredited VE: W5YI, ARRL
ARRL Instructor
1039 N 2575 W
Layton, UT, 84041-7709
USA
e-mail: sre.1966@gmail.com
phone: (801) 444-3445
cell: (801) 336-7635
------------------------------
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