[TowerTalk] help with interference problems

[jeremy-ca]

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 
switch; another toroid is there.

Alls quiet from 160 to microwave.

The big benefit is the speed, way above anything that cable or DSL offers 
around here.

Carl
KM1H


----- Original Message ----- 
From: "David Jordan" <wa3gin at comcast.net>
To: "'Stone, Gary R.'" <Gary.Stone at va.gov>; <towertalk at contesting.com>
Cc: <fsiebenthall at sbcglobal.net>
Sent: Tuesday, July 17, 2007 10:12 AM
Subject: Re: [TowerTalk] help with interference problems


> Gary,
>
> I just went through a similar problem using Ethernet extenders.  The 
> problem
> is that the frequencies used on the CAT5 are typically in the 7-10MHz 
> range.
> The vendor was very accommodating and provide me with another kit that
> utilized 3Mhz-5MHz.  I tested them and the results on 40m were impressive,
> no problem but when I went to 75M the circuit just waffled and died, haha.
> Ethernet extenders are devices that operate a lot like BPL, just over
> twisted pair TELCO lines. The CAT5 has more twist (I've heard) and better
> attenuation of the RF signal, but they are still RF signals...
>
>
> There are two approaches I would suggest you try:
>
> - remote your wireless radio antenna with LMR-400 or 600.  Get the box as
> far away from the current nodes of the 40m antenna. Ensure your CAT5 run 
> is
> not resonant anywhere close to 7-10MHz. Place about a dozen 1/2" ID 
> ferrite
> clam shells on the LMR to the wireless AP to ensure no RFI is coming down
> the coax to the box.
>
> - get some shielded CAT5
>
> I dropped the Ethernet extenders and installed a adhoc wireless network
> between my barn and house. I ran 75ft of LMR-600 to the 2.4GHz antenna. No
> more RFI problems.
>
>
> Good Luck,
> Dave
> Wa3gin
>
>
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