I found this paper quite interesting and it might solve some of our
spectrum issues.http://downloads.bbc.co.uk/rd/pubs/whp/ ... WHP204.pdf
Although it addresses DAB and DVB-T the same ideas would work
with DVB-S/S2. For a novice the maths might appear daunting however for anyone
'skilled in the art' it is not difficult to understand. There are pictures to help
with the explanation.
- Charles G4GUO
On Channel Repeaters
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This forum is run by the BATC (British Amateur Television Club), it is service made freely available to all interested parties, please do not abuse this privilege.
Thank you
Re: On Channel Repeaters
There are also some efforts in that direction for digital communication systems to enable full-duplex links. http://sing.stanford.edu/fullduplex/ is an implementation.
It might not be useful for traditional weak-signal amateur radio, but sure is interesting. I recall some article about an additional TX signal cancelling based on judicious antenna placement, but I don't find the link anymore.
73
Matthias
HB9EGM
It might not be useful for traditional weak-signal amateur radio, but sure is interesting. I recall some article about an additional TX signal cancelling based on judicious antenna placement, but I don't find the link anymore.
73
Matthias
HB9EGM
Re: On Channel Repeaters
A couple of days ago I starting playing with a small program I wrote using Scilab
that plots a simple polar plot of an array of antennas and it is quite interesting to see
what you can do by phasing multiple antennas.
I have added an optimisation routine to the program which allows me to specify an angle
and then the program works out the phasing required to place an null in that direction.
It then plots the radiation pattern of the antenna. It assumes the antennas are point sources.
It can only cope with optimising 2 antennas at present but I will extend that to an arbitrary
number of antennas.
This should give me an idea of the minimum number of antennas and the minimum spacing
required to produce a practical system. When DATV-Express is finished I may start on
the design of an FPGA based multi channel receiver.
- Charles G4GUO
that plots a simple polar plot of an array of antennas and it is quite interesting to see
what you can do by phasing multiple antennas.
I have added an optimisation routine to the program which allows me to specify an angle
and then the program works out the phasing required to place an null in that direction.
It then plots the radiation pattern of the antenna. It assumes the antennas are point sources.
It can only cope with optimising 2 antennas at present but I will extend that to an arbitrary
number of antennas.
This should give me an idea of the minimum number of antennas and the minimum spacing
required to produce a practical system. When DATV-Express is finished I may start on
the design of an FPGA based multi channel receiver.
- Charles G4GUO