Having an "10Ghz LNB" whose LO is QRT I decided to inject a tunable
Gunn source into the LNB mixer instead. Initial tests seems to indicate
that this arrangement performs well as a 10GHz receiver. It might get
around the objection of simple wideband systems having a poor Noise
Figure. No doubt too by some judicious switching the Gunn oscillator
could also be used as the source in transmit mode.

While searching the web I also came across this site on converting
LNB's to 10GHz operation which might be of interest:-

http://www.bvdavies.org.uk/dvd_03lnb.htm

73 de Chris