[RFI] HV Transmission Line

[K1TTT]

On hv lines that have glass or porcelain suspension type insulators with
individual disks ( strings of things that look like these:
http://www.berkshireinsulatorgallery.org/catalog_porc_brown.html).  You can
count the number of disks in a single string and multiply by 20kv to get in
the ballpark.  Then usually round down to the next common voltage used in
your area.  Around here 115kv and 345kv are common, other areas of the
country may have 230kv, 500kv(big!), 765kv(REALLY big!), and some have 69kv,
138kv and a few other voltages.  

There are very specific specifications for rfi from hv lines and if you are
getting interference, especially if it is getting worse, you should contact
the company and let them know... they usually will be interested because an
increase in interference usually means something is starting to break down
and its much better to get it before it causes an outage on the line.

Some companies may fool you by putting more insulators in the strings than
are needed for the voltage they are running.  This can happen in areas of
high contamination from ocean spray or industrial pollution.  They can also
do it in advance of a system upgrade so they can increase the voltage by
replacing the transformers without having to replace the insulators also.


David Robbins K1TTT
e-mail: mailto:k1ttt at arrl.net
web: http://www.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
 

> -----Original Message-----
> From: Jim Miller KG0KP [mailto:JimMiller at STL-OnLine.Net]
> Sent: Tuesday, October 13, 2009 21:23
> To: k9mk at flash.net; AE5B; RFI Reflector
> Subject: Re: [RFI] HV Transmission Line
> 
> How do you know the voltage on the high lines?  I have big lines running
> through my property in the country and know they are way above 14.4 or
> anything near that but how can you tell?
> 
> 73, de Jim KG0KP
> 
> ----- Original Message -----
> From: <k9mk at flash.net>
> To: "AE5B" <ae5b at arrl.net>; "RFI Reflector" <RFI at Contesting.com>
> Sent: Tuesday, October 13, 2009 3:46 PM
> Subject: Re: [RFI] HV Transmission Line
> 
> 
> > John,
> >
> >    I have a 345Kv line about a mile west of me.  The high lines are dead
> > quiet when compared to the noise coming from the 14.4Kv distribution
> plant
> > that feeds our community.
> >
> > Mike K9MK
> >
> > -------------- Original message from AE5B <ae5b at arrl.net>: -------------
> -
> >
> >
> >> Lot of windmill power in West Texas. Lot of customers in East Texas. As
> a
> >> result, 300 miles of 345 kV transmission lines will soon be built
> through
> >> my
> >> area. Two of the four proposed routes will cross portions of my ranch.
> >> One
> >> proposal would have a line running approximately a mile from the ranch
> >> house. Is
> >> that far enough away that I shouldn't worry?
> >>
> >> John
> >> AE5B
> >>
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> 
> 
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