Why Tilt ? - The Terminated Tilted Folded Dipole (TTFD / T2FD) Antenna
RHF
Why Tilt ? - The Terminated Tilted Folded Dipole (TTFD / T2FD) Antenna
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/9085
Terminated Tilted Folded Dipole (TTFD / T2FD) Antenna
http://en.wikipedia.org/wiki/T2FD
http://www.electronics-tutorials.com/antennas/antenna-basics.htm
http://www.hard-core-dx.com/nordicdx/antenna/wire/t2fd.html
http://www.hard-core-dx.com/nordicdx/antenna/wire/t2design.html
http://www.hard-core-dx.com/nordicdx/antenna/wire/t2fdfeed.html
http://www.hard-core-dx.com/nordicdx/antenna/wire/t2fdcomp.html
http://www.hard-core-dx.com/nordicdx/antenna/wire/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/info/antennas/dipole/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/info/antennas/dipole/folded_dipole.php
http://www.qsl.net/w4sat/fdipole.htm
http://www.arcticpeak.com/antennapages/folded_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/antenna/wire/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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- - - In Shortwave-...@yahoogroups.com,
- - - "rulex44" <rulex44@...> wrote:
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/9076
>
> Hi fellas.
>
> Why TTFD ot T2FD has to be installed neccesarily tilted.
>
> What kind of grounding in order to avoid sorrounding
> noise do you suggest for his one.
>
> Regards. Raúl
>
.
.
. .
.
Han
As far as I know , you have to tilt the antenna to get the right
reveiving curve/ angle. for distant stations it is good to receive low
incoming signals . By tilting this is achieved.
I use a 17 meter long T2FD for over 10 years and it is a antenna which
not gives a high signal level but a clean signal!
I see this as an advantage
Greetings Han, the netherlands
You can also visit my website
http://home.wanadoo.nl/hanhardonk/indexengels.html it contains a lot of
recordings of radiostations below 30 MHz
RHF
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/9086
>
> Hi there fellas.
> After some months of retirement from the forum I got a
> question, don't know is this was issued before.
>
> Regarding T2FD antennas, why they got to be installed
neccesarily tilted.
WellBrook T2FD Antenna
http://www.wellbrook.uk.com/UMBT2FD.html
The T2FD Antenna when laid Flat {Horizontal} Radiates
Off-the-Sides more then the Ends and thus is Bi-Directional
(two-way) vice Omni-Directional (All-A-Round).
The "Tilt" is usually about 20-30 Degress.
With Longer T2FD Antennas have less Tilt and
Shorter T2FD Antennas having more Tilt.
http://www.johncon.com/john/T2fd/
http://www.universal-radio.com/catalog/sw_ant/0562.html
Tilt ? - See Figure # 9
http://www.cebik.com/wire/t2fd.html
> Arnie Coro said don't set them like Inverted "V".
http://www.radiohc.org/Distributions/Dxers/ttfd2.html
> How much affects if T2FD is placed in a horizontal way?
Less Omni-Directional and more Off-the-Sides.
> And also important, how they got to be properly grounded
> to avoid sorrounding noise, as I have change the use of
> 300 Ohm T.V. line for 75 Ohm coaxial in a 4:1 disposition,
> but noise doesn't ended at all.
Noise is relative and for your location you would have
to start with :
1. A 1/4 WL Vertical Antenna as your High Noise
Reference Antenna
2. Then use a simple Horizontal 1/2 WL Dipole as your
Moderate Noise Reference Antenna.
3. A smaller multi-turn Vertical Loop Antenna for your
Low Noise Reference Antenna.
There are many things (factors) that can contribute to
the amount of Noise that you Hear on your Antennas.
* Location of the Antenna
* Placement of the Antenna
* Localized Noise Sources
* Type of feed-in-line
* Placement routing of the feed-in-line
* Antenna Grounding
* Radio Shack Grounding
TIP - If your Radio can be run by Battery. Take the
Radio Out-Side and connect it to your Antenna. Check
the Reception and the Noise Levels. If the Reception
is very good and the Noise levels are low : Then the
Noise Sources are most likely related to the In-Side
of your Home : AC Power Equipment-Appliances-Lights;
the AC Power Source Mains; and poor Shack Grounding.
> Regards. Raúl
>
Terminated Tilted Folded Dipole (T2FD / TTFD)
Antenna Size and Frequency :
http://en.wikipedia.org/wiki/T2FD_Antenna
http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=817
Bigger T2FD Antenna designed for the lower Shortwave
Frequencies 3-18 MHz would be roughly 33m (110 Feet)
Long, with a Space of 1m (3.3 Feet) between the Wires.
Average T2FD Antenna designed for the most Shortwave
Band Frequencies 5-30 MHz would be roughly 20m (66 Feet)
Long, with a Space of 60cm (2 Feet) between the Wires.
Smaller T2FD Antenna designed for the middle 31 Metters
Shortwave Frequencies (9.75 MHz)would be roughly 10m
(34 Feet) Long, with a Space of 30cm (1 Feet) between
the Wires.
International Broadcasting Shortwave (SW) Bands
http://en.wikipedia.org/wiki/Shortwave_bands
http://www.hamuniverse.com/swguide.html
http://shortwave.hfradio.org/
http://www.radios4you.com/shortwave-listening.html
http://www.etoncorp.com/US/support/shortwave_101.aspx?index=4
hope this helps - iane ~ RHF
.
All are WELCOME and "Invited to Join" the
Shortwave Listener (SWL) Antenna eGroup on YAHOO !
<http://groups.yahoo.com/group/Shortwave-SWL-Antenna/>
SWL ANTENNAS GROUP => http://tinyurl.com/an6tw
.
Some Say: On A Clear Day You Can See Forever.
I Believe : On A Clear Night You Can Hear Forever
. . . and Beyond , , , The BEYOND ! ! !
With a Shortwave Listening Antenna of your own making.
"If You Build It {SWL Antenna} You Will Hear Them !"
<http://groups.yahoo.com/group/Shortwave-SWL-Antenna/>
SHORTWAVE ANTENNA FORUM => http://tinyurl.com/an6tw
.
The Shortwave Listener's (SWL) Blessing :
May You Never Tire of Listening to the Radio and Always have
Strong Signals and Noise Free Reception ~ RHF {ibid}
RHF
To repeat myself :
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 ?)
Meaning :
The Variable Height above Ground favors no one specific
Frequency; and as the Receive of Transmit Frequency
varies the "Tilt" aids in accommodating all Frequencies
within the Band Width of the T2FD Antenna design.
Dale Parfitt
"Han" <websi...@yahoo.com> wrote in message
news:1145352024....@j33g2000cwa.googlegroups.com...
> Hello
>
> As far as I know , you have to tilt the antenna to get the right
> reveiving curve/ angle. for distant stations it is good to receive low
> incoming signals . By tilting this is achieved.
>
> I use a 17 meter long T2FD for over 10 years and it is a antenna which
> not gives a high signal level but a clean signal!
>
> I see this as an advantage
>
> Greetings Han, the netherlands
>
>
alter the takeoff angle (or elevation of the main lobe).
Download the demo version of EZNEC and you can see this for yourself.
The elevation angle is purely a function of height above ground of the
current loop(s).
Dale W4OP
RHF
Horizontal, Vertical and Sloping Dipole Antennas
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/9090
HORIZONTAL DIPOLE ANTENNA :
A basic Horizontal 1/2 WL Dipole Antenna that is Flat
with the Center mounted at 1/4 WL above-the-ground
and existing in a plane parallel to the ground; can be
said to Radiate mostly Off-the-Sides and not the ends.
This Horizontal Dipole Antenna has a predictable
Take-Off-Angle.
- - - The Surface of the Ground acts as a Reflector causing
the majority of the Signal to go Up and Off-the-Sides of
the Wire Antenna Element in a Horizontal plane : Making
the Horizontal Dipole Antenna mostly a Upwardly Radiating
Bi-Directional Antenna.
VERTICAL DIPOLE ANTENNA :
Conversely a basic Vertical 1/2 WL Dipole Antenna that
is Straight-Up-and-Down with the Center mounted at 1/4
WL above-the-ground and existing in a plane perpendicular
to the ground; can be said to Radiate Equally-All-Around;
but not off the ends. Again this Vertical Dipole Antenna
has a predictable Take-Off-Angle.
- - - Again the Surface of the Ground acts as a Reflector
and the majority of the Signal to go Up and Equally Around
(Still Off-the-Sides) the Wire Antenna Element in a
Horizontal plane : Making the Vertical Dipole Antenna an
Upwardly and Outwardly Radiating Omni-Directional Antenna.
30 DEGREE SLOPING {SLANTED} DIPOLE ANTENNA :
So we come to a 30 Degree Sloping Dipole Antenna that
is Slanted at an Angle Off-the-Horizontal {Vertical?} with
the Center mounted at 1/4 WL above-the-ground. Here the
majority of the Signal can be said to Radiate Off-the-Sides
but a portion of the Signal will Radiate Equally-All-Around;
but still not off the ends. As you point-out the Take-Off-Angle
would be closer to the Horizontal [Flat] Dipole Antenna.
NOTE - The lower Tip of this Slanted Dipole Antenna is
3/16 WL above the ground and the upper Tip is 5/16 WL
above-the-ground and the Vertical Dimension of the 30
Degree Sloping Dipole Antenna is 1/8 WL which makes
it effectively a 1/8 WL Vertical Radiator.
- - - Again the Surface of the Ground acts as a Reflector
and the majority of the Signal will go Up and Off-the-Sides
of the Wire Antenna Element in a Horizontal plane; however
some of the Signal does radiate in-all-directions in the
Horizontal plane : Making the 30 Degree Sloping {Slanted}
Dipole Antenna less of a bi-directional Antenna and more
of an omni-directional {semi-omni} Antenna.
Well that is the way that I 'envision' the Radiation properties
of the 30 Degree Sloping Dipole Antenna in my-minds-eye 8;-}
T2FD / TTFD ANTENNA :
Back to Why "Tilt" the Terminated Tilted Folded Dipole (TTFD /
T2FD) Antennas - - - The above rational is my simple understanding
of One-of-the-Whys for the 'tilting' of the Terminated Tilted Folded
Dipole (TTFD / T2FD) Antennas. To help slightly improve the
Omni-Directional characteristics of the basic Dipole Antenna in
this more Broad Banded design and application.
Oops ! - IIRC - FWIW - I am frequently right . . .
except when I am wrong, Wrong. WRONG !
{ Please Educate and Enlighten Me - Should I Be :-}
very little science coupled with mostly common sense - iane ~ RHF
[ Keeping It Simple ad Practical = KISAP :<]