[TowerTalk] Takeoff angle

john at kk9a.com john at kk9a.com
Mon Jul 24 10:07:53 EDT 2017

I have BOP on 40m and I found it to be completely useless, even for
domestic contests.

John  KK9A - W4AAA

Subject:	Re: [TowerTalk] Takeoff angle
From:	"StellarCAT" <rxdesign at ssvecnet.com>
Date:	Mon, 24 Jul 2017 08:37:28 -0400
List-post:	<mailto:towertalk at contesting.com>

I AM saying I am hearing this. This is not just the result of modeling, which
shows indeed that the highest angle will be favored (less often of course)...
this is a result of day to day operation ... why would I say otherwise?!
I’d say a good 10% of the time ... rough estimate, the BOP is favored over
BIP! That is HERE, in South Carolina by the way – where I am of course – not
where you are or where anyone else is – but those higher angle/distance
would move to another part of the world if from a different location.
I’d surmise that propagation where you are far north from here would
indeed be
different... I’m not saying what I’m seeing would be identical to every one
else. And I don’t doubt you see what you see...
Also when I had a 3 stack – and that was through the peak of the cycle but it
was from AZ (2005 – 2012) I never, not once, saw anything but all in phase be
the best on 20 ... last my first experience with being able to select was
in 2008 when I was operating a contest from ILL ... I was operating 15 single
... I had a 5 element mono at 90’ .... and I had, just days before the
received, assembled and installed a KLM 6 element 15 at 25’ on the tower
a fear of heights that was the best I could do by myself) ... over the whole
contest the lower antenna was essentially useless... until the last few hours
when all of a sudden EU was 10 – 15 db stronger on the lowest one ...
so I’m not sure what you’re protesting. This IS what I’ve seen ... as they
YMMV. Obviously it does.
Oh and as a side note – in AZ I did not have the ability to go BOP. It is BOP
that primarily is the best selection here – NOT using just the bottom antenna
alone. My experience using the bottom alone mimics yours - although I have
maybe twice seen the bottom alone perform better – its only when I am BOP
I see as much as 10 db difference (on a calibrated S meter by the way).
The reason why I brought it up is if considering a stack one might consider
going with a matching device that allows BOP ... I’m glad I did. Again: YMMV!

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