5 ms·

Curtain Antenna

51 points by jhallenworld 11y ago

madengr 11y ago
Now here is a dipole array: https://en.m.wikipedia.org/wiki/Duga-3 https://en.m.wikipedia.org/wiki/Duga-3
- grendelt 11y ago
  So. much. gain. As a ham radio operator this is the sort of antenna array we fantasize about using.
  - grandalf 11y ago
    Speaking of which, in this book Tom tells a story about connecting an amateur transceiver to a massive broadcast array in Hawaii: http://www.n6bt.com/n6bt-AAOL-3rd-1.htm http://www.n6bt.com/n6bt-AAOL-3rd-1.htm
- Daneel_ 11y ago
  Non-mobile version: https://en.wikipedia.org/wiki/Duga-3 https://en.wikipedia.org/wiki/Duga-3 I remember reading about this and being astounded at the transmission power. 10MW is a phenomenally strong broadcast power.. Amazing.
- jhallenworld 11y ago
  Wow.. I wonder if the feedline scheme for this antenna is simple.. as in would it be easy for some pirates to borrow it for their transmissions :-)
etimberg 11y ago
Antenna arrays are immensely powerful. The described design is a special case of a general phased array where the phase difference between elements is 0 degrees. With electronically controlled delays between elements, it is possible to make an electronically steerable antenna. The are lots of possibilities for using beam steering antennas, especially for power optimization.
- privong 11y ago
  > With electronically controlled delays between elements, it is possible to make an electronically steerable antenna. Multiple current and future radio telescopes are using this technique with dipole arrays at low frequencies, including LOFAR[0], the LWA[1], and eventually the SKA[2]. [0] http://lofar.org/ http://lofar.org/ http://link.springer.com/chapter/10.1007/978-3-642-23397-5_33 http://link.springer.com/chapter/10.1007/978-3-642-23397-5_3... [1] http://lwa.phys.unm.edu/abouthome.html http://lwa.phys.unm.edu/abouthome.html [2] https://www.skatelescope.org/ https://www.skatelescope.org/
jhallenworld 11y ago
I've been listening to shortwave recently (I bought a new radio: a TECSUN PL-880). The 36 most easily received stations include Radio Habana, China Radio International and 34 Christian stations. These Christian broadcasters must be very concerned about us here in the Northeast :-) https://en.wikipedia.org/wiki/WRMI https://en.wikipedia.org/wiki/WRMI http://wtww.us/pages/transmitters.php http://wtww.us/pages/transmitters.php Well, now that I'm looking at, WTWW now has Art Bell. Will try for that tonight.

Curtain Antenna

51 points by jhallenworld 11y ago

madengr 11y ago

Now here is a dipole array: https://en.m.wikipedia.org/wiki/Duga-3 https://en.m.wikipedia.org/wiki/Duga-3

grendelt 11y ago
So. much. gain. As a ham radio operator this is the sort of antenna array we fantasize about using.
- grandalf 11y ago
  Speaking of which, in this book Tom tells a story about connecting an amateur transceiver to a massive broadcast array in Hawaii: http://www.n6bt.com/n6bt-AAOL-3rd-1.htm http://www.n6bt.com/n6bt-AAOL-3rd-1.htm
Daneel_ 11y ago
Non-mobile version: https://en.wikipedia.org/wiki/Duga-3 https://en.wikipedia.org/wiki/Duga-3 I remember reading about this and being astounded at the transmission power. 10MW is a phenomenally strong broadcast power.. Amazing.
jhallenworld 11y ago
Wow.. I wonder if the feedline scheme for this antenna is simple.. as in would it be easy for some pirates to borrow it for their transmissions :-)

etimberg 11y ago

Antenna arrays are immensely powerful. The described design is a special case of a general phased array where the phase difference between elements is 0 degrees. With electronically controlled delays between elements, it is possible to make an electronically steerable antenna. The are lots of possibilities for using beam steering antennas, especially for power optimization.

privong 11y ago
> With electronically controlled delays between elements, it is possible to make an electronically steerable antenna. Multiple current and future radio telescopes are using this technique with dipole arrays at low frequencies, including LOFAR[0], the LWA[1], and eventually the SKA[2]. [0] http://lofar.org/ http://lofar.org/ http://link.springer.com/chapter/10.1007/978-3-642-23397-5_33 http://link.springer.com/chapter/10.1007/978-3-642-23397-5_3... [1] http://lwa.phys.unm.edu/abouthome.html http://lwa.phys.unm.edu/abouthome.html [2] https://www.skatelescope.org/ https://www.skatelescope.org/

jhallenworld 11y ago

I've been listening to shortwave recently (I bought a new radio: a TECSUN PL-880). The 36 most easily received stations include Radio Habana, China Radio International and 34 Christian stations. These Christian broadcasters must be very concerned about us here in the Northeast :-) https://en.wikipedia.org/wiki/WRMI https://en.wikipedia.org/wiki/WRMI http://wtww.us/pages/transmitters.php http://wtww.us/pages/transmitters.php Well, now that I'm looking at, WTWW now has Art Bell. Will try for that tonight.