I don't have a linear LNB for the 18" dish, just the one circular one, so I can't test this out. I would love to try to get in
IA5, or Galaxy 10 on the 18" dish.
You could measure it and tell us how far across it is in inches or cm.
All that I can get on my 18" DBS dish is Dish Net satellites and Nimiq 1 and 2. Not much FTA programming on those though. NASA and WOUB mostly all that I can watch, but a few splash screens with cool jazz.
Bill