Rob:
There are some HV transmission lines directly over the Calumet Trail in the=
Dunes National Lakeshore at Beverly Shores, In. I am not sure if these line=
s are
at=C2=A0345 KV tension, but it=C2=A0seems like=C2=A0they could very well be=
. I tried once to
bike along that trail, but the intensity of the electric field was so inten=
se
that I quickly got a headache and abandoned the idea of riding along that t=
rail.
Over the a period of 10 years, I have only seen one cyclist using that trai=
l. My
opinion, subjectively, is that the field is too intense for comfort within =
150
feet for personal comfort. I have no idea how birds react to it, but I don'=
t
believe that I have seen any fowl=C2=A0at all=C2=A0close to that field. The=
E-field
intensity directly under those lines is generally expressed in volts per me=
ter,
so if the potential is 345 KV and the height of the lines is 30 meters, the=
n the
field intensity is 11.5 KV/m. This means that if you stood directly under t=
hose
line, your head would be at a potential of 69,000 volts higher than the sol=
es of
our feet. No wonder I got a headache!
One thing of note about=C2=A0this area is that it=C2=A0is very marshy direc=
tly north of
those power lines. I suspect that the water works as a very effective groun=
d
plane which would have the effect of shunting the electric field to ground =
very
quickly, thus dissipating the E-field quickly. I have done quite a bit if
recording 2500 feet to the north of these lines without any adverse effects=
using both unbalanced PIP-powered electrets on my PCM-M10 as well as with
AT-4022s at max gain on an FR2-LE without picking up any hum whatsoever.
But when I attempted to use=C2=A0various antennae for picking up sferics (l=
oop
antenna or E-field high-impedance whip) the AC hum was intense and intolera=
ble (
I can send you this if you want it). So unless you have a serious wet
marsh/water=C2=A0directly on both sides of those transmission lines, kiss y=
our
pristine recordings and wildlife goodbye. It is very sad that this has to
happen. I believe that in Europe it is common to have the HV transmission l=
ines
buried underground which would mitigate much of the harmful effects of the=
E-field=C2=A0that overhead lines produce. There would perhaps be some H-fie=
ld
(magnetic) lines of force from such an arrangement, but the effects to wild=
life
would be greatly reduced. Check this out:
http://en.wikipedia.org/wiki/Electric_power_transmission
Good luck in shooting this proposal down. I've been to Kickapoo and it is a=
very
beautiful place!
Take care,
Greg
=C2=A0
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