"Hal Rosser" wrote in message
...
This may be - to communicate with submarines (VLF).
So your assumption that its multiple wavelengths long may be unwarranted.
It may be a quarter-wave, half-wave or any portion (or multiple) of a
wavelength.
.

"ml" wrote in message
...
hi

i was just reading about airforce plans that had a trailing wire which
when fully extended was 6miles long


From:

http://jproc.ca/radiostor/vlfelf.html

In the United States military, the primary means of communicating with
submerged submarines is the TACAMO (Take Charge and Move Out) system which
uses a fleet of aircraft. Two aircraft are always airborne - one over the
Atlantic and one over the Pacific. Other aircraft are stationed on the
ground and they are on a 15 minute alert. The aircraft fly 10.5 hour
missions, starting at one airfield and ending at another. Random patterns
are flown to mislead any unauthorized observers. The TACAMO aircraft can
receive and relay signals from a number of different ground command posts.
Each aircraft is equipped with a 6.2 mile long trailing wire antenna (wound
on a reel) and a 100 kw transmitter operating in the VLF region. When the
aircraft has to transmit a message, it banks and proceeds to fly a very
tight circle. The causes the trailing wire antenna to hang vertically below.
Once the message is transmitted over the VLF downlink the aircraft resumes
normal flight.
The TACAMO fleet was initially comprised of the Lockheed Hercules EC130
aircraft, but these are being gradually phased out and replaced with the
Boeing 747 AWACS type aircraft. These aircraft have the capability to
transmit a 200 kw signal using a 2.5 mile trailing antenna. The systems
described above were documented in a book printed in 1985. Due to
unavailability of information, I do not know if the same system is still in
use in the 1990's, but the techniques, nonetheless are quite intriguing.

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