Raúl,

Why Tilt ? - The Terminated Tilted Folded Dipole (TTFD / T2FD) Antenna
http://groups.yahoo.com/group/Shortw...a/message/9085

Terminated Tilted Folded Dipole (TTFD / T2FD) Antenna
http://en.wikipedia.org/wiki/T2FD
http://www.electronics-tutorials.com...nna-basics.htm
http://www.hard-core-dx.com/nordicdx...wire/t2fd.html
http://www.hard-core-dx.com/nordicdx.../t2design.html
http://www.hard-core-dx.com/nordicdx.../t2fdfeed.html
http://www.hard-core-dx.com/nordicdx.../t2fdcomp.html
http://www.hard-core-dx.com/nordicdx...re/t2fd_1.html
http://www.radiohc.org/Distributions/Dxers/ttfd2.html

An Antenna that incorporates these Four Design Elements
to achieve Broad Banded performance :
1. Terminated
2. Tilted
3. Folded
4. Dipole Antenna
http://www.cebik.com/wire/t2fd.html


Starting with #4 the Basic DIPOLE ANTENNA.
http://www.radio-electronics.com/inf...ole/dipole.php
http://www.ycars.org/EFRA/Module%20C/AntDip.htm
The Dipole is generally a Half-Wave Antenna 'cut' for
one Specific Frequency; Mounted at a Set Height for
that Frequency and Positioned for a general Off-the-Sides Broadcasting
and Receiving. Usually the Dipole is mounted
Flat some times in an Inverted "V" or Sloping and even
Vertical.
http://en.wikipedia.org/wiki/Dipole_antenna
How High should my Dipole be ?
http://www.qsl.net/aa3rl/ant2.html
FWIW - The Radiation Resistance of a properly installed
Half-Wave Dipole Antenna is 75 Ohms.


The FOLDED Dipole #3 is simply a Dipole that is Folded
Back Over on Itself making it Double. If one Dipole is
a Half-Wave Antenna then it follows that a Double Dipole
is a Half-Wave Antenna Times-Two = a Full-Wave Antenna.
The Folded {Full-Wave} Dipole generally has better Band
Width then the Half-Wave Dipole Antenna. Most often the
Fold Dipole is mounted Flat and sometimes Vertical. The
directional characteristics of the Folded Dipole Antenna
again are Off-the-Sides for Broadcasting and Receiving.
FWIW - The Radiation Resistance of a properly installed
Folded {Full-Wave} Dipole Antenna is 300 Ohms.
http://www.radio-electronics.com/inf...ded_dipole.php
http://www.qsl.net/w4sat/fdipole.htm
http://www.arcticpeak.com/antennapag...ded_dipole.htm
TV type Folded Dipole Antenna
http://www.wfu.edu/~matthews/misc/dipole.html


TILTED #2 is used to get the T2FD Antenna off the Horizontal
where much of the signal is Off-the-Sides and give the
Wire Antenna Elements a little Vertical Dimension to make
the Antenna Radiate all around equally in all directions.
Tilting also varies the Height-above-Ground of the Antenna
and thus the relationship of the Wire Antenna Elements to
the Ground has no one specific frequency as in the Basic
Dipole Antenna. {Ground Reactance ?)

RAUL - SO TO ANSWER YOUR QUESTION
Titlting helps to make the T2FD Antenna Omni-Directional.


TERMINATED #1 is used to match the impedance characteristics
of the Folded Dipole Antenna over a much broader Frequency
range then the un-terminated Folded Dipole.


TWO SHORTWAVE LISTENER (SWL) T2FD ANTENNAS :
NOTE - For the Shortwave Listener this T2FD or TTFD
Terminated Tilted Folded Dipole (T2FD) Antenna design
seems to be preferred. It uses a 4:1 Matching Transformer
(Balun) and a 75 Ohm Coax Cable feed-in-line with a
390 Ohm Terminating Resistor.
http://www.hard-core-dx.com/nordicdx.../t2design.html
Or this Terminated Tilted Folded Dipole Shortwave Listener's
(SWL) Antenna that uses a 10:1 Balun with a 50 Ohm Coax Cable
feed-in-line with a 470 Ohm Terminating Resistor.
T2FD = http://www.johncon.com/john/T2fd/


GROUNDING of the Terminated Tilted Folded Dipole (T2FD)
Antenna is not required since it is a form of a Dipole
Antenna an in an of itself does not require a Ground to
make it a fully functioning Antenna. However your Radio
Shack should have a good earthen Ground Connection and
through your Radio Shacks equipment the T2FD will have
a Ground Path of sorts. To that end ensure that you have
a good earthen Ground Connection for your Radio Shack that
is Bonded to your House's Electrical System.


hope this helps - iane ~ RHF
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