You are substantially in the near field at 200' ... 2000' feet would be more
like it on 80 meters. 10 wavelengths is where you want to be so on 80 that
is 2600'. 40 1300' ... 20 600' ... and an S unit on that rig, on most rigs
now days is closer to 3 db and is roughly linear except at the low end (on
my FT5K it is <2 db change to go from S5 down to S1). I'd think absorption
by the trees more so in the summer with leaves is going to have some impact
on 20 meters.
That stated it appears to work - don't sweat it - enjoy it!
Gary
K9RX
-----Original Message-----
From: Mike Smith VE9AA
Sent: Friday, October 14, 2016 4:14 PM
To: towertalk@contesting.com
Subject: [TowerTalk] Wire 4-squares - they work ! (GAIN?)
de Mike VE9AA again. Can't seem to get this reply onto the list, but see
other messages showing up. I apologize if this is a dupe !
A couple folks asked me where I was getting my gain and F/B #'s from.
Fair question.
First of all, I have no doubt the S-meter on an IC-7410 is not accurate, but
everything is relative.
I just performed these measurements moments ago using my AA-230PRO as a
signal source about 200' Southwest of all 3 arrays and also equidistant to
the ref antenna which is an HF9V which also has raised radials. On 20 & 40
this is probably a pretty fair ref. antenna. On 80m, not so much.
I'll express them in S-units, and someone wiser than I can extrapolate to
dB/S-unit if they happen to know it as fact for this radio.
First, all 3-arrays have metallic clutter (or each other), or an 160m
inverted L very much in the near field.). A couple delta loops for 15m & 20m
are also close by.
All readings taken with a SW source/signal generator ~ 200' away.(my
AA-230pro)
From my understanding an S-unit on a modern Icom is somewhere between 3 -
6dB ?....is it linear from S1-S9 (doubt it)
20m
HF9V - S7
Array - SW - S8
SE - S2
NE - S1-2 (varies a little with the wind.call it S1.5)
NW - S3
Gain over ref 3-6dB? F/B 18-36dB?
40m
HF9V - S5
Array - SW -S6
SE - S2
NE - S2
NW - S3
Gain over ref 3-6dB? F/B 12-24dB? Low due to being nested inside NW
quadrant of 80m array?
80m
HF9V - S5 (unfair reference)
Array - SW - S8
SE - S3
NE - S0 (could hear signal, can't measure it)
NW - S6 <ouch; would've thought # should've been lower here,
however this array aimed NW is aiming at all other antennas and a garden
shed, cars, etc. so maybe I should not be surprised)
Gain over crappy vertical 9-18dB? (real gain 3dB?) F/B Excellent @ 24-48dB
So, it's obvious it all doesn't work perfectly, and F/S seems to suffer a
little here and there, but compared to the reference antenna, they have some
gain and F/B is pretty good. F/S is fair.
I don't know if at only 200' away this is a fair or accurate test.
Mike VE9AA
Mike, Coreen & Corey
Keswick Ridge, NB
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