On Dec 21, 7:19*pm, RHF wrote:
On Dec 21, 3:26*am, wrote:





Dear All,

I have some beginners questions regarding antennas:

*** Why is it difficult to design and construct HF transmit antennas
for high power PEP, compared with low power 100 W?
Conceptually what is the difference between the two in design,
material construction?
Why do people find the high power harder to design and construct?

*** I understand that omnidirectional antennas transmit in all
directions with almost equal gain. Is it hard to design HF antenna
with directional gain in one direction and minimum in other
directions?
How is this done( conceptually): electrical length, material
contruction?

*** HF wire antennas: can these be for high power transmission and
directional gain ( guess the would always be omnidirectional)?

*** How is angle of transmission with the horizon (elevation)
controlled in a HF antenna ?

*** Can receive antennas also be diectional or are they always
omnidirectional receiving from all sides?
Do receive antennas have power ratings?

Thank you

Vijay

Vijay,

? Are you talking about High Power 1~2 KW Rated Antennas
vice Low Power 10~100 Watts Rated Antennas for use in
Amateur {Ham} Radio Broadcasting ?

* Check-Out the American Radio Relay League (ARRL)
ARRL -http://www.arrl.org/

* The ARRL Handbook for Radio Communicationshttp://www.arrl.org/catalog/?item=NO-HB2008

* The ARRL Antenna Bookhttp://www.arrl.org/catalog/?item=9876

* The ARRL *Antenna Compendium Volume 7http://www.arrl.org/catalog/?item=8608

* Thje ARRL Practical Wire Antennas # 2http://www.arrl.org/catalog/?item=9563

? Or are you talking about High Power 50/100/250/500 KW
Antennas for Shortwave Broadcast Radio use ?

* HRS Type Antennas are more or less the Standard Antenna
used for Long Distance High Power Shortwave Broadcasting.http://en.wikipedia.org/wiki/HRS_type_antennas
Th HRS Antenna is Curtain Antenna composed of a Dipole
Array; consisting of Rows and Columns of Dipoles.http://hireme.geek.nz/HRS_antennas.html

* * ALLISS is a fully rotatable Antenna System
for High Power Shortwave Radio Broadcasting.http://en.wikipedia.org/wiki/ALLISS

* * Dipole Antenna {Hertzian}http://en.wikipedia.org/wiki/Dipole_antenna

* * Log-Periodic (LP) Antenna Arrayhttp://en.wikipedia.org/wiki/Log-periodic_antenna

* * Antenna (Radio)http://en.wikipedia.org/wiki/Antenna_%28radio%29

* International Shortwave Radio (HF) Broadcastinghttp://en.wikipedia.org/wiki/International_broadcasting

* Shortwave Radio operates between the High Frequencies
(HF) of 3 MHz (3,000 kHz) and 30 MHz (30,000 kHz)http://en.wikipedia.org/wiki/Shortwa...High_frequency

iane ~ RHF
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Amateur Radio Society of India (ARSI)
http://www.qsl.net/vu2msy/ARSI.htm
ARSI - http://www.arsi.info/
http://www.qsl.net/vu2msy/HAMCLUBS.htm
http://en.wikipedia.org/wiki/Amateur...ciety_of_India

National Institute of Amateur Radio (NIAR)
http://www.niar.org/aboutus.html

~ RHF