Topband: prospective QTH evaluations
Herb Schoenbohm
herbs@vitelcom.net
Fri, 25 May 2001 16:01:10 -0300
Eric,
It is important to know the level of HV and the type of construction, i.e. 3
phase, copper or aluminum wire, metal or wood power poles, new or old, treated
or dry etc.
At my QTH on ST. Croix the beach is about 900 feet away. Along the road, which
runs parallel to the shore, is a 3 phase 7.6 KV (all aluminum) power
service.(Each pole ground is copper) It is only 30 feet from the water, in most
cases, and is quiet as a church mouse. I believe that the reason for this is
because it is a fairly new construction service, replaced after Hurricane
Marilyn in 1995, and because the surf breaks out 2 miles on the reef thus
limiting the shoreline salt spray.
I have checked many locations similar to this on the island and where the
construction is new and installed by a good crew, in our case by visiting
fireman from Alabama Power, seldom is there a noise power line reason for
serious noise. Where I did find problems it was generally due to tree branches
or problems with transformer hardware.
The AM car radio is not the best detector or locator of power line noise. A
portable short-wave
receiver such as the Grundig Yacht Boy or the Sangean ATS404 ($89.95 in he
recent MCM flyer), used in AM mode, and on the highest band where the noise is
desernible, is a better locator. By moving up the spectrum it is easier to get
close to the source of the noise without being confused by power line
re-radiation nodes. If the area you are looking at is fairly rural and not in a
urban or suburban setting, the existing noise from any source, should be easier
to deal with.
There are so many other factors such as time of day, time of year, humidity,
industrial pollutants, plant growth, and even bird droppings. It would take a
longer period of time than a casual drive by to evaluate a location to be
absolutely sure. A much better investment might be to take the manager of the
line department out to lunch.
Good luck,
Herb Schoenbohm, (ex-KV4FZ)
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