No, if the signal is off boresight it will miss the feedhorn. It has to be
pretty well aligned with the main beam.
From: Steve Jones
Sent: Thursday, March 11, 2021 3:34 PM
To: AnimalFarm Microwave Users Group
Subject: Re: [AFMUG] multipath on a reflector
id considered something like this but to make it a functional thing it would
have to monitor the two radios and turn up or down a port based on better
performing system. the guy with the two radios doesnt complain, prefers to not
have to wait on us to come move it up to the roof or down to the post. its
cheaper than a truck roll twice a year.
but to the original question, a ground reflected wavelength to a parabolic
antenna, is that reflected off the top half of the dish into the feedhorn?
On Thu, Mar 11, 2021 at 4:23 PM Chuck McCown via AF <af@af.afmug.com> wrote:
Since none of the PMP vendors have a space diversity option, I wonder about
just putting up two radios and bonding them at the ethernet level. If it is
multipath fading, both radios should not be faded at the same time. Would OSPF
or RSTP or EIGRP be able to deal with this scenario?
From: Steve Jones
Sent: Thursday, March 11, 2021 2:44 PM
To: AnimalFarm Microwave Users Group
Subject: Re: [AFMUG] multipath on a reflector
this is one that was part of a group of similar issues. We had one that is
white paper level multipath. I can tell you the day and time they start the
harvest across the street and the time they finish it. that one we ended up
just installing 2 radios and they swap power supplies twice a year.
this one is facing west and looking at it the dips begin sharply around 4pm
the last week, around noon the week before. thats about the time it starts to
cool back down, not that its all that warm. its muddy fields so the surface is
soggier in the day, firms up more when it cools. yesterday was super windy and
it didnt do it, probably the soil is dryer.
IIRC i have her radio right now peaking over the ridge of the roof from her
tower.
Im planning on going out and putting it on a 12 foot post to halve the
fresnel, sable marginal is better than unstable marginal.
the first guy i mentioned here is actually a pretty cool case. this general
region is super high iron content in the soil, we have another area this is
really common and their soil samples are really high as well, i dont know if
iron oxide is more reflective han dirt dirt or if certain circumstances make it
that way. or could be whatever causes the soil to be more iron rich causes it.
or soil content could have nothing to do with it. I had gotten the sample
results from a soil testing joint thats a customer, thought i could figure it
out but its one of those things somebody smarter than me could probably figure
out.
On Thu, Mar 11, 2021 at 3:23 PM Brian Webster <i...@wirelessmapping.com>
wrote:
Doe this customer have the issue at a certain time of the day? Maybe around
sunrise or sunset. It may be possible that it’s not multipath but at certain
times of the year the antenna has a good path to picking up noise from the sun
and that could be stronger than your AP signal? This usually is exhibited on
paths that have an East/West orientation. Depending on the gain of the antenna
it can be worse than others. Think of the sun either just above the horizon at
sunrise or sunset and the focal beam on the antenna is such that it picks up
that noise enough to be stronger than the AP. Depending on the time of year,
tilt angle of the Earth etc., it looks like a seasonal issue.
Thank you,
Brian Webster
www.wirelessmapping.com
From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Steve Jones
Sent: Thursday, March 11, 2021 1:36 PM
To: AnimalFarm Microwave Users Group
Subject: [AFMUG] multipath on a reflector
our APs sit between 90 and 110 feet on average in flat terrain so we deal
with alot of seasonal ground reflectivity issues. We have this one customer
presenting again with whats probably multipath fading, I had tried putting a
shield on the bottom half of the reflector once out of curiosity. It didnt do
much
what im wondering though is how the ground reflected multipath feeds into
the feedhorn.
is it reflecting off the top half of the dish and into the feedhorn like a
mirror?
--
AF mailing list
AF@af.afmug.com
http://af.afmug.com/mailman/listinfo/af_af.afmug.com
------------------------------------------------------------------------------
--
AF mailing list
AF@af.afmug.com
http://af.afmug.com/mailman/listinfo/af_af.afmug.com
--
AF mailing list
AF@af.afmug.com
http://af.afmug.com/mailman/listinfo/af_af.afmug.com
--------------------------------------------------------------------------------
--
AF mailing list
AF@af.afmug.com
http://af.afmug.com/mailman/listinfo/af_af.afmug.com
--
AF mailing list
AF@af.afmug.com
http://af.afmug.com/mailman/listinfo/af_af.afmug.com
