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Old June 21st 04, 05:11 AM
G.Beat
 
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"Kees" wrote in message
...
Hello fellow shortwave listeners !

More info to make a T2FD yourself, like I did mine, please have a
look at:

http://members.home.nl/rita.kees/t2fdmake.html

I hope you can appreciate it and use it for your practice.

I will be glad to answer your questions.

73/cheers

Kees


The Tilted Terminated Folded Dipole ("T2FD") is a broadband folded dipole
antenna design that provides a relatively
stable feed point impedance over about a five to one frequency range. The
antenna
length in meters is approximately 100 divided by the lowest desired
operating
frequency in megahertz. The upper element of the folded dipole is opened in
the
center and a non-inductive terminating resistor of around 350-400 ohms is
inserted.
The bottom element is fed in the center through a 6-to-1 balun for a good
match to
50 ohm feed line.

The antenna is not as efficient as a matched half wave dipole at any
specific
frequency, but it also does not require an antenna tuner for operation,
making it
easy to use. The loss of receiving efficiency is not generally noticeable
in the high frequency range (2-30 MHz), amounting to less than 6 db (one
standard
S-unit) during extensive on-the-air testing.

Here is additional information on the T2FD antenna.

Barker & Williamson actually applied for a US patent (US Patent #4423423)
for their specific T2FD antenna design.
http://www.fact-index.com/t/t2/t2fd_antenna.html

While this may be acceptable for SWL operation, the resistor does not have
sufficient wattage for
any station attempting to use this for a transmitting antenna.
http://www.tuberadio.com/tfd.html

http://www.universal-radio.com/catalog/sw_ant/0562.html


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