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Re: [TowerTalk] help with interference problems

To: James Wolf <jbwolf@comcast.net>, towertalk@contesting.com
Subject: Re: [TowerTalk] help with interference problems
From: Larry DiGioia N8KU <towertalk@longwire.com>
Date: Thu, 19 Jul 2007 19:58:08 -0400
List-post: <mailto:towertalk@contesting.com>
I am wondering why anyone needs to run gigabit to their ISP 
antenna/radio, when the fastest speed you could possibly get through the 
wire from your ISP is *maybe* 8 to 10 megabit...?

James Wolf wrote:
> At 09:48 PM 7/17/2007, Roger (K8RI) wrote:
>
>   
>>> My Internet link is a 5.6GHz radio at the 100' level on the tower with
>>>       
> an
>   
>>> 11
>>> mile shot to the ISP. I come down the tower with shielded CAT5 to the
>>> router
>>> in a trailer at the base of the tower; this is run with about 8 turns
>>>       
> thru
>   
>>> a
>>> FT240-43 toroid . Then a 250' run of regular CAT5 to the house and a 8
>>> port
>>>       
>> Lordy...I'm running a gigabit network through 130' of CAT5e parallel to and
>> within about 5 to 10 feet of all the coax runs to the tower. (75 to 90
>>     
> feet)
>   
>> It then runs under the 75 half wave sloper to the shop. I found that even a
>> metal staple used to loosely hold the cable created enough inductance to
>> screw up the network.  It won't work in metal conduit either.
>>     
>
> I would be surprised if you ever get this running right at 1Gb speeds.
> Gigabit speeds on Ethernet are really fussy and very susceptible to
> interference.  The only thing you have going for you is that it is shielded
> cable, which does help.
> - Don't make sharp bends in the cable.
> - Don't run the cable next to other cables.
> - Don't crush the cable with tie wraps etc.
> - GB Network cards that are on the MB are notoriously poor in performance.
> A 'good' aftermarket card usually works better.
> - Again, very susceptible to interference.
> - This appears not to be a problem, but If your runs are more that 100
> meters, then since the velocity factor of the twisted pair sets in the cable
> are different, (to eliminate crossover issues) the signals arriving at the
> far end are too far enough out of sync.
>
> If you are still unsuccessful, look into using single mode fiber if you can.
>
> James Wolf, KR9U
>
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>
>
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>   

-- 
Larry  N8KU

 l o n g w i r e . c o m
 HF - DX - CW - Digital

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