Towertalk
[Top] [All Lists]

[TowerTalk] A Question of GAIN

To: <towertalk@contesting.com>
Subject: [TowerTalk] A Question of GAIN
From: k2av@qsl.net (Guy Olinger, K2AV)
Date: Tue, 20 Oct 1998 18:35:28 GMT
Try to start off without all the quotes, think everyone has them
all...

My take on the multipathing was to demonstrate to a doubter that it
was not possible to figure the behaviour of a stack on receive in the
same manner as a single yagi, and that results coming into the stack
were a different thing than results at the other end coming off the
stack.

I was not attempting to take on the entirety of fading, faraday
rotation, etc. I really haven't had the opportunity to experiment with
incoming signals at various angles and rotations on HF. I would *love*
to have the time and the means.

Also, I was *trying* to be brief (keep the laughter to a dull roar,
please). Many of the posts on these subjects are quite long, and for
the casual reader, lack the helpful topic and summary paragraph. We
allow ourselves the somewhat lazy and difficult (for the reader)
tactic of using the organization of the prior post as a skeleton.

I am not as ready as Tom to dismiss the rather broad vertical nulls in
20-10m yagi patterns at 60+ feet as a large factor in stack behaviour
during fades. 

I hear two kinds of stories. One where signals are coming in at a
certain angle, often rather low, and the other where multiple paths
are active with different time delay, different incoming angles,
different incoming directions, and different polarizations. 

I spoke to the first, only. I would be interested in how one goes
about measuring and verifying the latter. One would have to accumulate
a significant data base of measured occurences to start to predictably
model these effects. 

As to using the common kinds of BC antennas as a reverse engineering
inference for what does what in fading... 

 Although part of me finds that argument appealing, I would point out
that even US Government bureaucracies have budgets and are run by
conservative types with typical protect-your-own-backside first
attitudes. I would bet that multimillion-dollar risktaking is minimal
to experiment in new fade-rejection antenna techniques for
high-powered broadcast stations. Spend monely first on concepts
already proven to work, in use around the world. One can use this to
rule a concept *in*, but not to rule something else *out*. A research
project like this sounds more like the military or academia.

That said, I really appreciate the discussion. Fire on...

73, y'all
Guy

Guy L. Olinger
k2av@qsl.net
Apex, NC, USA

--
FAQ on WWW:               http://www.contesting.com/towertalkfaq.html
Submissions:              towertalk@contesting.com
Administrative requests:  towertalk-REQUEST@contesting.com
Problems:                 owner-towertalk@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm


<Prev in Thread] Current Thread [Next in Thread>