20-07-2017, 02:26 AM
For background, have a look here:
http://www.itu.int/en/ITU-R/terrestrial/..._Annex.pdf; go to page 63.
The conclusion was that orthogonal polarization was worthwhile doing to reduce co-channel interference. It was acknowledged that results could be variable by site. The measured median benefit was 18 dB, with 90% of sites at or above 10 dB.
The UK situation may have been an extreme one, in that Band I at least was “overstuffed” to the point where non-trivial mutual interference was inevitable.
This item from Wireless World 1966 February about the opening of the Gloucester channel 1H relay is telling.
It included the comment: “For satisfactory reception of BBC-1 transmissions very careful positioning of the aerial may be necessary to avoid interference from other stations using this channel – particularly the high power station at Crystal Palace.”
Cheers,
Steve
http://www.itu.int/en/ITU-R/terrestrial/..._Annex.pdf; go to page 63.
The conclusion was that orthogonal polarization was worthwhile doing to reduce co-channel interference. It was acknowledged that results could be variable by site. The measured median benefit was 18 dB, with 90% of sites at or above 10 dB.
The UK situation may have been an extreme one, in that Band I at least was “overstuffed” to the point where non-trivial mutual interference was inevitable.
This item from Wireless World 1966 February about the opening of the Gloucester channel 1H relay is telling.
It included the comment: “For satisfactory reception of BBC-1 transmissions very careful positioning of the aerial may be necessary to avoid interference from other stations using this channel – particularly the high power station at Crystal Palace.”
Cheers,
Steve
