|
Sep 1st, 2015 at 11:17am
I can only give part of the answer.
Each of the 82 spot beams has 250 MHz bandwidth and I believe there are 3 carriers each occupying 65 MHz and one carrier occupying 50 MHz of allocated bandwidth. I would guess these carriers are 52 and 40 Msps 8PSK 5/6 with information bit rates of 130 and 100 Mbit/s giving a total of 490 Mbit/s per beam, shared amongst the number of customers per beam. These figures are 'clear sky'. In rain the modulation type and FEC change to maintain service with lower information rates.
A typical customer, with a 500 MHz wide receiver, will see 4 high level wanted carriers on the wanted polarisation occupying half the rx cable bandwidth, plus possibly 4 lower level carriers from one adjacent beam. Using the wrong receive polarisation a customer might see 8 lower level carriers from two adjacent beams.
If anyone has spectrum analyser plots of what they can see it would be helpful to put them here. Send to me eric@satsig.net
|
