Need info about Pyramid antennas and it's performance
 

Hi All,

I am a SWL from India and hope to get a ticket soon. I am constructing
a simple receiver and i would like to construct a good antenna for my
receiver and in future for my transmitter as well. I came across a
design in a souvenir released by Hamfest India where an antenna called
"Pyramid Antenna" is described. The author gave reference to one design
published in Radio Magazibe 1982 by Steve Bauer,DJIUS. I came across
another similar design described in
http://www.warc.org.uk/clubmag/qsx13.pdf . I would like to know more
about this antenna and the experience of using it, about it's
performance. My house is near a 11KV power line and my antenna will be
less than 15 feet from the above said power line.

Thanks in advance.

Regards
Shan
SWL

Need info about Pyramid antennas and it's performance
 

On 28 Mar 2006 02:33:09 -0800, wrote:

Hi All,

I am a SWL from India and hope to get a ticket soon. I am constructing
a simple receiver and i would like to construct a good antenna for my
receiver and in future for my transmitter as well. I came across a
design in a souvenir released by Hamfest India where an antenna called
"Pyramid Antenna" is described. The author gave reference to one design
published in Radio Magazibe 1982 by Steve Bauer,DJIUS. I came across
another similar design described in
http://www.warc.org.uk/clubmag/qsx13.pdf . I would like to know more
about this antenna and the experience of using it, about it's
performance. My house is near a 11KV power line and my antenna will be
less than 15 feet from the above said power line.

Thanks in advance.

Regards
Shan
SWL


That's too close.

Need info about Pyramid antennas and it's performance
 

I'm afraid you will have to find a better spot for the antenna. The
power line you mention will be a source of too much noise. In fact, I
can hardly imagine a more potent source of rfi....well, wait a minute,
let me try:

http://youtube.com/watch?v=RM3SxDw7uMs

Three Antennas : Pyramid Antenna - Inverted "L" Antenna - Tilted Terminated Folded Dipole Antenna (T2FD)
 

SHAN,

PYRAMID ANTENNA :
Your Pyramid Antenna would be more aptly described as :
Two Delta Loop Antennas fed out of phase; having a
common fed-point at Apexes; and Slanted at -30 Degrees
and +30 Degrees from the Vertical.

ANTENNAS AND POWER LINES :
Now as to placing this Antenna or any Antenna directly
under the or very near Power Lines : It is not and I repeat
NOT recommended [.]
- - - First consider a smaller simpler Antenna that is further
away from the Power Lines. (20m Inverted "L" Antenna
10m Up and 10m Out -or- 5m Up and 5m Out)

BASIC INVERTED "L" ANTENNA FOR
THE AMATEUR {HAM} OPERATOR
Dr. Ace's [WH2T] Inverted L Antenna Info
ILA = http://www.bloomington.in.us/~wh2t/invertedl.html
http://groups.yahoo.com/group/Shortw...na/message/309
http://groups.google.com/group/rec.r...f4e4ded6f94686
NOTE: The Amateur/HAM Inverted "L" Antenna is usually made-up
of Two Equal Sections One Vertical 'Leg' and One Horazontal 'Arm'.
These Two Equal Section can be:
* 1/8th Wavelength = Quarter Wavelength Total
* 1/4th Wavelength = Half Wavelength Total
* 1/2th Wavelength = One Wavelength Total
Because of the 'equal' porportionality, the Amateur / HAM
Inverted "L" Antenna is most often Higher above the Ground
then the SWL Version.
Note - For Amateur Radio use the basic common
20m 1/2 WL Inverted "L" Antenna is :
= 1/4 WL on 40m
= 1/8 WL on 80m
= 1 WL on 10m

FWIW :
- Why not place this Pyramid Antenna in the Attic like
the original magazine article did ?
- If you have a Pitched Roof this Pyramid Antenna can
be Laid Top of the Roof using Insulated Wire.
- If you have a Flat Roof then this Pyramid Antenna can
be Laid Flat on a Roof using Insulated Wire.

ALTERNATIVE : T2FD ANTENNA
To the Pyramid Antenna for an out-side location consider
the Tilted Terminated Folded Dipole Antenna (T2FD)

Hard Core DX - "T2FD Antenna" - Info and Design Links
GoTo= http://www.hard-core-dx.com/nordicdx...ire/index.html
- - - The Terminated Tilted Folded Dipole (T2FD)
- - - The "T2FD" is a Broad All Band Antenna for SWL.
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

More About the Terminated Tilted Folded Dipole (T2FD)
* How To Build the TTFD : A Broadband Antenna for
Shortwave Reception - by Arnie Coro [RHC] Dxers Unlimited
http://www.radiohc.org/Distributions/Dxers/ttfd2.html
* Modeling the T2FD - by L.B. Cebik [W4RNL]
http://www.cebik.com/wire/t2fd.html

The Formulas for Calculating Terminated Tilted Folded
Dipole (T2FD) Dimensions are found at :
http://www.hard-core-dx.com/nordicdx.../t2design.html

Simple {No Math} Just-Cut-It T2FD Antenna :
In order to cover the main portion of Shortwave (5 - 30 MHz),
a T2FD Antenna will be roughly 20m (66 feet) long, with a
spacing of 60 cm (24 inches). With the Top-End mounted
about 40 Feet High and the Bottom-End mounted at 7 Feet
with a 30 Degrees from Horizontal Slant Top-to-Bottom.


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