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HF Noise Generated by Ubiquity Bullets

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Fri, 12/18/2015 - 20:20
#1
n4km
HF Noise Generated by Ubiquity Bullets

Hi Guys,
I didn't know anywhere else to go with this topic, so I came here. I am using several Ubiquity Bullets on 2.4 and 5.8 Ghz, some running stock firmware for wifi access and some running AREDN. They seem to generate a tremendous amount of noise on the HF frequencies. I powered them all down and powered up one in the shack and the needle on my HF radio jumped 3 S units. I have tried the snap on ferrite at each end of the cables and one the power supply for the POE. I have also tried a stand alone POE adaptor. The bullet that I was playing with in the shack, I even wrapped it in aluminum foil and grounded it to the connector. Anybody got any ideas on how to quiet these things down?
TNX and 73,
Kevin N4KM 

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Sat, 12/19/2015 - 09:57
KE2N
KE2N's picture
noises

I slip ferrite cores over my shielded cables, at ech end, before installing the connector and use RF Armor on my M5 Rockets.  
A bullet would be harder to shield.
I found this:
http://community.ubnt.com/ubnt/attachments/ubnt/airMAX_Troubleshooting/18198/1/foilbullet.jpg
apparently it is a combination of aluminum tubing and metal tape.

GL
 

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Sat, 12/19/2015 - 13:04
K5DLQ
K5DLQ's picture
I've heard that some of the
I've heard that some of the UBNT PoE adapters can be noisy.  I'd start there.

 
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Thu, 12/31/2015 - 09:47
n4km
Working on it
Hey Thanks guys,
I am working on the problem little by little. I think I am going to buy stock in ferrite, the price is sure to go up with all that I am buying. Little by little I am seeing the noise decrease. Still working on getting some quieter power supplies, but I can see that everything I am doing it helping.
Thanks for the input!
73,
Kevin N4KM
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Fri, 01/01/2016 - 12:11
kg9dw
kg9dw's picture
passive POE
You could also ditch all of the ubiquiti brick power supplies and use passive POE injectors (search ebay). I picked up a few from China for like $1.50 a piece. I plug them into my station's master 12v power supply. My cat5 runs are pretty short. Just another option for you to try.
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Sat, 01/02/2016 - 14:35
(Reply to #5)
wb6tae
passive PoE
Excellent suggestion.  I am sure any good station 12v supply is cleaner than the noisy Ubquity bricks.  If the runs are long, it might make sense to run the 12v up the tower using large gauge wire and then mount the PoE injectors in a waterproof box on the tower.

BTW, I found these PoE injectors from Amazon. They are quite compact, cost $2 ea., and have a power indicator LED.
 
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Sun, 01/03/2016 - 01:06
(Reply to #6)
WD6EBY
I recently completed a new
I recently completed a new HUB instillation in Ventura County.  Once installed and operational, it was derermined that I was creating so much noise for a 6Mtr repeater on the same tower that it was blowing squelch and going through the PL.  The following was discovered.  When using the standard Ubiquiti Pro Grade (Shield Only)cable with a standard PoE or a Switch PoE, with no data to the NODE, the 6Mtr system was operation well.  Once I started to pass data to the NODE, the noise floor for 6Mtr came up.  I suspect that the square wave data, with all of its harmonics, was radiating out the poorly shielded cables.

My solution.  I replaced all of the Network cable with Ubiquiti Carrier Grade cable, some 600 feet (Shield and Braid).  I purchased and installed Shield Kits for the Rocket Radios.  Finally I installed Ferrite cores in the Rocket Radio (inside the shielding) and into the back ends of the NanoBridge radios.

The final results are I am no longer causing any issues with the 6Mtr Repeater.  This upgrade has also increased my through-put a bit due to a reduction on noise coming into the system.

Hope this helps.

Paul...
WD6EBY
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