Right, if it's thermal ducting it's more to do with the weather than the
crop.
Thinking back now, the thing Ken Hohof was always on about was
reflections from the corn. He would get a gradual drop in signal as the
corn grew to a certain height....it would last for days, not hours.
------ Original Message ------
From: "Mike Hammett" <af...@ics-il.net>
To: af@afmug.com
Sent: 8/28/2017 10:40:54 AM
Subject: Re: [AFMUG] 5Ghz thermal fade w/ Corn
It happens to me shooting over a city with very little corn at all.
It'll happen anywhere there may be a lack of wind and different layers
of air density.
-----
Mike Hammett
Intelligent Computing Solutions <http://www.ics-il.com/>
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From: "Kurt Fankhauser" <lists.wavel...@gmail.com>
To: af@afmug.com
Sent: Monday, August 28, 2017 9:39:38 AM
Subject: Re: [AFMUG] 5Ghz thermal fade w/ Corn
would this still be happening if i was shooting over a bare field with
no vegetation or is this a corn related/exagerated effect?
On Mon, Aug 28, 2017 at 10:14 AM, Cameron Crum <cc...@wispmon.com>
wrote:
Would be interesting to see a graph related to temperature and
humidity vs signal strength to see if there is some ducting, or even
temp probes at different elevations during the event Also, how does
the corn plant itself behave during the day? Do the leaves lift or sag
or stay the same? Corn leaves are pretty wide and smooth. I wonder if
they could be acting like a nice smooth reflective surface due to a
rise of the leaves?
On Mon, Aug 28, 2017 at 7:49 AM, Adam Moffett <dmmoff...@gmail.com>
wrote:
Ken said he would (where possible) position the antenna so the center
of the path was passing over a tree.
I guess if the issue was destructive reflections off the corn then
the tree attenuates those reflections?
------ Original Message ------
From: "Chuck McCown" <ch...@wbmfg.com>
To: af@afmug.com
Sent: 8/27/2017 11:27:12 PM
Subject: Re: [AFMUG] 5Ghz thermal fade w/ Corn
First time I ever heard about this was many years ago from Ken
Hohof. Corn and pine trees seem to have a unique effect on RF.
From:Kurt Fankhauser
Sent: Sunday, August 27, 2017 8:43 PM
To:af@afmug.com
Subject: [AFMUG] 5Ghz thermal fade w/ Corn
I have a customer on a PMP450 SM at 5Ghz link only 2.8 miles out.
This SM normally sits at -62 or -65. Every evening for the last 2
months SM will fade to -80 or worse and sometimes even disconnecting
for a couple hours then it comes right back. AP is 120 feet height
customer CPE height is about 15' height
There is alot of corn fields across this link i have in the past
seen problems with corn links. I don't know why but shooting across
corn is sometimes a problem.
Other thing i thought of is the AP is mounted on top of of a very
large steel grain bin that probably is heating up during the day
maybe it is giving off heat when the sun first goes down we have
started to get cool in the evenings here.
I am about ready to move customer to a different frequency band he
is pissed his Netflix is not working during prime time.
