Towertalk
[Top] [All Lists]

Re: [TowerTalk] help with interference problems

To: "'Stone, Gary R.'" <Gary.Stone@va.gov>,<towertalk@contesting.com>
Subject: Re: [TowerTalk] help with interference problems
From: "David Jordan" <wa3gin@comcast.net>
Date: Tue, 17 Jul 2007 10:12:16 -0400
List-post: <mailto:towertalk@contesting.com>
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


_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk

<Prev in Thread] Current Thread [Next in Thread>