Direction of transmissions – Föreningen Alexander

Detta ämne har 3 svar, 3 deltagare, och uppdaterades senast för 8 år, 9 månader sedan av Peter van Baarle.

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18 januari, 2016 kl. 18:00 #4207 Svara

Peter van Baarle
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The total distance between first and the last antenna tower is 1900m. This equals approx. 10% of the wavelength, so there is a phase difference between the signals transmitted by the first tower and that of the last tower of around 36 degrees. And a proportional phase shift inbetween by the other 4 towers.
I guess this results in a certain direction effect by the antenna array. Has this been taken into account when designing the placement of the towers, assuming the transmissions were targeted to New York?
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- 29 mars, 2016 kl. 22:46 #4366 Svara
  
  Peter van Baarle
  Gäst
  
  Thanks for the info!
- 1 mars, 2016 kl. 11:19 #4328 Svara
  
  Arne Sikö
  Gäst
  
  When I made a calculation on the directivity on 17.2 kHz, the result was that the intensiy along the direction of the array of towers is 0.24 dB less than perpendicularly to it. The phase difference between consecutive towers is 7.8 degrees with 380 meters between the towers. So, the antenna must be practically omnidirectional at the frequency of SAQ. Of course, if nothing more was to be considered, it still should have been natural to direct the tower array for maximum towards NY, but i.e. land considerations might well have been more important.
- 27 januari, 2016 kl. 20:40 #4224 Svara
  
  Ola Hernvall
  Deltagare
  
  We agree with the opinion that the SAQ antenna is oriented for best radiation towards New York. Though, we have not seen any document that confirms this.
  
  Anyhow, the radiation pattern of the antenna is almost omnidirectional, with a slight increase in NW-SE direction and a dip in the NE direction.
  
  Radiation-SAQ
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