If these are all water tanks, you would probably be best served running
Fiber + DC to a small box at the top and use double-shielded cable from
the Netonix to the radios. I would use a metal enclosure so no noise
from the switch should be an issue. Some FP-1204 from Shireen would do
the trick for the cable run.
This would be far easier and less costly then conduit, liquid tight, or
running brand new cables to each radio.
Of course those solutions only work if it is the cable, and not the
radio itself causing the issue.
<https://atheral.com/>
Daniel White
Co-Founder - Business Development & Operations
direct: +1 (702) 470-2766
Facebook icon <https://www.facebook.com/getatheral> LinkedIn icon
<https://www.linkedin.com/company/atheral/> Youtbue icon
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Craig House wrote on 2/28/19 20:44:
It doesn't seem to be a particular radio. At one point we were
convinced it was some old 900 FSK radios that we removed eventually.
At one point we ran coax up to the omni and left the connectorized
radio at the base of the tower which solved that problem at that time
but it was the cable not the radio that was the problem. We later
added other UBNT and Cambium radios to the tower and the problem came
back. Added ferrite clamp beads and that reduced the problem but
didn't totally eliminate it. It does seem that the problem is
consistently with on particular guy that is installing the 911
equipment. No other towers that we have equipment on are as
drastically affected. Maybe it is his equipment or method of
installing but that doesn't solve our issue since the city and county
are wanting us to fix it since we added the equipment that makes it
not work. We are not using POE injectors in most cases. We used old
CMM3 when we had the first problem but that has not been the case at
the other sites. We have Netonix 24 and 8 port switches at the other
sites. I am thinking about the liquidtite but that is going to be a
pain to do on long runs. Grounding the shielded cable will be problem
midspan because this cat5 is single shielded with the mylar inner
jacket that is easy to cut and would probably not get a good ground.
So replacing all my networks links BH cables in hopes that fixes it
would be a lot of down time potentially for a "Hope it works"
attempt. I dont think we have our lines anywhere near the feed lines
on the water tower at one site. Putting them all in Liquidtite is
doable but on one water tower that means about 20 runs of it and I'm
afraid of how messy that will end up looking vs just the 20 cat5 runs.
How do the coils of cable help? you cant put them in the liquid tite
if they are coiled. Seems to be counter to the idea of containing the
RF but I'm not an RF engineer.
Thanks guys
------------------------------------------------------------------------
*From: *"Daniel White" <[email protected]>
*To: *"AnimalFarm Microwave Users Group" <[email protected]>
*Sent: *Thursday, February 28, 2019 9:19:23 PM
*Subject: *Re: [AFMUG] Interference with 911 repeaters
Craig,
While I've not experienced this on a network I was responsible for, I
have helped a few times while at various manufacturers troubleshoot
issues like this.
Some tips in addition to what Chuck has written:
- First make sure to localize which radio it is. Some radios are
particularly nasty in these cases. Go to the site and turn off
everything, then turn on each radio individually. You may find it is
a common radio at every site, and replacing those radios with another
brand/type might be easier.
- Bad switching power supplies can sometimes be the culprit. An easy
change is to replace the power supply/PoE injector.. ideally with a
different model (instead of the vendor supplied one try maybe a McCown
Tech injector). This can be the cause of the radio or cable affecting
the repeater.
- If the interference is adjacent or a harmonic notch filters or band
filters on the 911 repeater may be an easy solution
- Double shield cable works well if the noise is from the cable and
not the radio. Shireen DC-2022 or Superior Essex BBDGE would be best
bets... and these are also easy to ground with GKCAT5 from SitePro (or
something equivalent):
https://www.sitepro1.com/store/cart.php?m=product_list&c=14. For best
effect, use every 50ft of cable run and wrap around the outside double
shield.
While these issues suck to troubleshoot... narrowing it down to the
radio causing issues is key.
Good luck Craig (hope your doing well BTW!)
<https://atheral.com/>
Daniel White
Co-Founder - Business Development & Operations
direct: +1 (702) 470-2766
Facebook icon <https://www.facebook.com/getatheral> LinkedIn icon
<https://www.linkedin.com/company/atheral/> Youtbue icon
<https://www.youtube.com/channel/UCpPZv-EsGCj8LXfzylwCrjQ>
[email protected] wrote on 2/28/19 15:20:
I would first attempt to discover if it is the CAT5 or the radio
itself.
Ask the 911 guys if they have a spectrum analyzer they can lend
you to puzzle this out.
Shielded CAT5 helps.
Putting in coils at the ends helps.
Ferrite chokes help.
Some run it in liquidtight or full metal conduit.
You can put fiber media converters on the ends of a CAT5 and
perhaps fix it.
But every single ethernet device, every switch, hub, router, radio
does radiate noise. Just because they passed FCC
certification tests does not mean they are noise free. The 911
repeater probably has a high gain omni and probably a super low
noise pre amplifier too. So it will naturally be more sensitive
to noise than a normal 2 way repeater.
Isolating it to a particular radio or cable is a good place to start.
-----Original Message----- From: Craig House
Sent: Thursday, February 28, 2019 1:45 PM
To: [email protected]
Subject: [AFMUG] Interference with 911 repeaters
I think I’ve posted this question on here before but I want to
try again. We have multiple water towers where we have various
types of equipment a mix of Mimosa cambium and ubiquity
products. It seems that on many of these water towers our cat
five power over ethernet creates RF interference for the
repeater. In one instance we were able to install magnets that
clamped around the cable which did help enough they stopped
complaining. In other cases we’ve attempted to move our
equipment from the top of the water tower down to the catwalk
to create some distance and installed the ferrite beads with
little success at all. I’m tired of playing with ideas that
might or might not work. Can someone give me advice that will
solve this problem once and for all. I understand that
grounding the CAT5 might help I’ve also been told that putting
our wires inside of conduit might help or shortening the wires
might help. I don’t want anymore might help I would like
someone who has actually done this to be able to give me some
advice
Sent from my iPhone
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