"Doug" wrote in
ink.net:

I have had a tour of the transmitters and antennas at US Navy
transmitter site at Cutler, Maine where they run up to 3 MW output
power at 17.6 KHz. They replace elements in the tubes and pump the
vacuum back down. The helix coils at the antenna feed are massive.
When ice starts to load down an antenna array, they put AC power
through the antenna to ground so the antenna wire heats up and sheds
ice. Doug K7ABX


If you are ever near Ft Collins, Colorado, go bang on the front door of
NIST's WWV time stations, the frequency and time references for the world.
Those guys love to take techie touristas on a nickel tour of the plant.
WWVB on 60 Khz isn't as exciting as it was in the old days when they had
the massive antennas, though. Their 60 Khz antennas are more modern now
and don't flashover near as excitingly as they once did.
http://www.boulder.nist.gov/timefreq/stations/wwvb.htm
No, Gary, they don't have 1250 meter towers, which is the ELECTRICAL length
of 60 Khz 1/4 wave. They use loading so the electrical length is 5000
meters on towers with a PHYSICAL length of only 125 meters. The capacitor
hat is HUGE! They use three 38KW transmitters to get 50KW ERP from 3
phased antennas with about 57% efficiency. This greatly reduces the
electrical stresses on very high powered helix houses like Cutler's.

Hee hee....we should send Gary Shafer to Cutler so he can learn about the
electrical length of an antenna being different from the physical length of
an antenna with loading coils and capacitor hats....(c; The electrical
length at that freq is a hair over 5 miles for a simple dipole...(c;

You should see the rhombic antennas at NW Cape, Australia the Navy has run
for years near Canarvon. The locals are so afraid of the flashovers they
won't go anywhere near them!...(c;

Larry W4CSC
POWER IS OUR FRIEND!