May I ask an ignorant question. QO100 currently uses different polarisation on the WB and NB transponder.
There is a similar one-sentence requirement in the AMSAT-UK answer to the ESA request.
"why do these polarisations have to be different?"
To prevent mutual interference in the same frequency band (?)
To prevent mutual interference in the same frequency band (?)
That is the thing, really. Looking at QO100 as example, the wideband transponder (10491-10499) output is on a different frequency as the narrowband transponder (10489.500-10490). Is the different polarisation required as isolation to prevent signals leaking in the other passband?
On the flipside, using the same polarisarisation means that the same LNB can be used to receive both signals. Currently that is not the case - QO100 requires a duo-LNB, one H-polarized, one V-polarized channel, to receive both signals.
