There is some info here on static dissipation for repeaters.
http://www.repeater-builder.com/rbtip/
You'll have to dig for it. They also have a mailing list you may want to
sign up for.
73
Jim W7RY
--------------------------------------------------
From: "Kipton Moravec" <kip@kdream.com>
Sent: Friday, April 22, 2011 7:11 PM
To: <towertalk@contesting.com>
Subject: [TowerTalk] Corona Electromagnetic Interference
> Our repeater antenna is located on a 180 foot water tower.
>
> We have not had a problem in the 4 years it has been up there. It is
> used for Skywarn nets when we have bad weather in the county.
>
> The past two storms this year the noise was so bad it was hard to hear
> the mobile stations, and even the NCS who is normally full quieting at
> 20W had to increase his power to 75W on 2M to be heard.
>
> The noise seemed to happen when the storms were around and cleared up
> once they passed. It seemed constant not the crackle from lightning.
>
> Someone who knows a lot more than me said it was Corona.
>
> This is a 1.5M gallon water tank. It has a 18" pipe with a column of
> water going to ground. There are at least 8 braided ground wires from
> the tank to the ground spread evenly down the concrete support.
>
> We have a 270 foot 1 5/8" coax going from the base to the tip side of
> the tower. The VHF repeater where we seem to be having the most
> noticeable problem has a Decibel Products antenna (with a grounded mast
> and 4 loop elements on the side each 90 degrees apart and a matching
> harness). We have one for the 2M repeater and one for the 70cm repeater
> both using the same coax coming up the tower and splitting with a
> diplexer to the two antennas on the top of the tower.
>
> Hopefully there is enough background information on what we have.
>
>
> What can we do about the corona EMI?
> How do we get rid of it?
> Why are we just noticing it this season, and not before?
> Could something be going bad? What?
>
> We are going to be checking the site in the morning. What should I be
> looking for?
>
>
> --
> Kipton Moravec AE5IB .- . ..... .. -...
>
> "Always do right; this will gratify some people and astonish the rest."
> --Mark Twain
>
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 10.0.1321 / Virus Database: 1500/3591 - Release Date: 04/22/11
>
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|