I've got my beads! Should I put them on both end of the cable?
-RickG

On Wed, Apr 29, 2009 at 11:27 AM, Marlon K. Schafer
<o...@odessaoffice.com> wrote:
> Yeah, the beads are amazing!  We're starting to use them on almost all tower
> installs.
>
> Supposed to help with lightning too.  Though we've not had enough of that
> around here for a couple of years to really be able to see any difference.
>
> The worst part about the beads is getting the right ones!  I'm still not
> sure we're using the right stuff.  sigh  Ours are big enough that we can
> (and do) wrap the cat 5 through them 3 turns.  More turns is supposed to be
> better.  Whatever it is, they've REALLY cleaned things up at my FM radio
> station site!  Our customer compliant calls have dropped by 80 to 90% out
> there!  Wish I'd have really understood what was happening out there 4 or 5
> years ago when the new station went online.  I always thought I was ONLY
> fighting the massive amounts of 2.4 gig interference in the area.  That's
> still a problem, but much more easily dealt with than I'd ever have
> imagined.
>
> marlon
>
> ----- Original Message -----
> From: "Eje Gustafsson" <e...@wisp-router.com>
> To: "'WISPA General List'" <wireless@wispa.org>
> Sent: Wednesday, April 29, 2009 8:10 AM
> Subject: Re: [WISPA] Noise by me on a tower
>
>
>> Ethernet crystal harmonics. The crystal on Ethernet is 25MHz. So your
>> hitting them with the 9th harmonics. This bleeding is worst with PoE
>> powered
>> devices because it couples into the DC power over the cat5 cabling and if
>> the power supply is not nice and clean it will couple into the AC system
>> as
>> well. I have been involved in certifying 4 radios in a FCC certification
>> lab. Each time we ran into this problem especially when powered by PoE. A
>> different power supply could make a huge difference but also installing
>> ferried beads on the cat5 cabling (close to the radio port, directly after
>> the poe device out port and directly on the poe data in port) cleaned up
>> this emission. Using shielded cable will help on equipment that is picking
>> up this radiated signal directly from the cat5 cabling but if it's bad
>> enough and the powersupply isn't good enough the harmonics signal will go
>> out into the AC source unless ferried beads been installed properly.
>>
>> On one of these devices I helped getting certified we had to make it
>> mandatory to have these beads installed to be able to pass (product never
>> made it to market).
>>
>> / Eje
>> CTO
>> WISP-Router, Inc.
>>
>> -----Original Message-----
>> From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On
>> Behalf Of Steve Barnes
>> Sent: Wednesday, April 29, 2009 10:02 AM
>> To: WISPA General List
>> Subject: [WISPA] Noise by me on a tower
>>
>> I have an odd situation, I have 2-2.4 180* sectors MT RB411 and 5-5.8
>> StarOS
>> War1 backhaul radios and a RB600 router at the top of a 265ft old AT&T
>> microwave tower. The top has a grounded NEMA metal box and POE powered by
>> an
>> Allen Bradley converter. I have an AC and an Ethernet run to the base
>> where
>> I have a APC UPS.
>>
>> The owner just leased space to another client 20 Feet away on same level
>> from me.  It is a local REMC doing meter reading on 221Mhz.  They were
>> having problems with receiving they brought in a spectrum analyzer and
>> there
>> was a noise floor of -71 at 220Mhz.  The tower owner being an radio guy
>> not
>> a wireless guy just killed power on the ups. (taking down all my stuff and
>> locking up 1 one of the radios for an hour GRRR)  When our equipment was
>> off
>> the noise floor went to -108.  As soon as he powered me back up the noise
>> returned.  They actually said that there was noise from around 150Mhz to
>> 240Mhz.
>>
>> Everything is grounded and cased in metal except the LMR that goes to the
>> Antennas, the AC wire is in flex and the shielded Ethernet down the tower.
>>
>> Ideas? there might be a little noise off the oscillators of the War-1
>> boards
>> but that's 175Mhz.  The Ethernet is 100Mhz, RB411 300Mhz and RB600 266 MHz
>>
>> Steve Barnes
>> RCWiFi Wireless Internet Service
>>
>>
>>
>> ----------------------------------------------------------------------------
>> ----
>> WISPA Wants You! Join today!
>> http://signup.wispa.org/
>> ----------------------------------------------------------------------------
>> ----
>>
>> WISPA Wireless List: wireless@wispa.org
>>
>> Subscribe/Unsubscribe:
>> http://lists.wispa.org/mailman/listinfo/wireless
>>
>> Archives: http://lists.wispa.org/pipermail/wireless/
>>
>>
>>
>>
>> --------------------------------------------------------------------------------
>> WISPA Wants You! Join today!
>> http://signup.wispa.org/
>> --------------------------------------------------------------------------------
>>
>> WISPA Wireless List: wireless@wispa.org
>>
>> Subscribe/Unsubscribe:
>> http://lists.wispa.org/mailman/listinfo/wireless
>>
>> Archives: http://lists.wispa.org/pipermail/wireless/
>
>
>
> --------------------------------------------------------------------------------
> WISPA Wants You! Join today!
> http://signup.wispa.org/
> --------------------------------------------------------------------------------
>
> WISPA Wireless List: wireless@wispa.org
>
> Subscribe/Unsubscribe:
> http://lists.wispa.org/mailman/listinfo/wireless
>
> Archives: http://lists.wispa.org/pipermail/wireless/
>


--------------------------------------------------------------------------------
WISPA Wants You! Join today!
http://signup.wispa.org/
--------------------------------------------------------------------------------
 
WISPA Wireless List: wireless@wispa.org

Subscribe/Unsubscribe:
http://lists.wispa.org/mailman/listinfo/wireless

Archives: http://lists.wispa.org/pipermail/wireless/

Reply via email to