THanks. Neat.
Re polarity, if you're talking RTN on ACM9, both east and west are on the same horizontal transponder, so getting those two doesn't mean you're getting both polarities. I can't imagine any way that you could get both polarities with a replacement LNB like a Norsat.
I'm curious whether you've had the lnbs off those things? If so, is the part you call the feedhorn open all the way to the LNB, or is it closed off with probes on both sides of where it's closed off (confusing wording)? Also, is the wave-guide where it connects to the LNB cylindrical or rectangular??
The reason I ask, is that replacement LNBs like a Norsat or Cal-Amp have rectangular wave guides, whereas with that narrow cylindrical throat almost certainly have a circular waveguide at the throat area, but perhaps it's closed off where it connects to the LNB, and converts to a rectangular waveguide, but that doesn't seem likely.
I have an *OLD* {1980s era} General Instruments LNBF that has a front section that looks similar to your feed, ie a broad scalar ring (mine's more conical), and a very small cylindrical throat, connecting to what seems to be an LNB via a round flange with numerous screw holes similar to yours. However on mine, it is a round waveguide on both sides of the flange. Ie I couldn't connect a replacement LNB because that would have a rectangular waveguide.
Anyway, I've never run into a small feedhorn like yours that would accept replacement LNBs. If it does, then that's interesting, but I really don't think it would do polarity switching.
Re the "hornets", there are many different kinds of hornets. The type mentioned above that make the HUGE nests would never build in a feedhorn. Also as mentioned above, usually it's wasps that build in feedhorns, and while they will sting, usually if you get a couple feet away from their nest, they will leave you alone, compared to a hornet, that will follow you across a yard into the house and out the door to the other side of the house. Hornets are really agressive. But the reason I'm commenting on the hornets, is that in addition to the big nest hornets, and yellow-jacket ground type hornets, the past several years, we've had a wierd type of hornet nest on our house/garage. I think I looked it up, and it was something like a white faced hornet. But their nests start out as the strangest looking things I've ever seen. Sort of a golf ball sized core where it connects to the building, and below that a long tube, about 1/2" diameter. Really wierd looking. It stays this way for quite a while, but eventually the hornet builds the paper covering around the long tube, but it never gets big, like those monster things. I've also seen another type of hornet that seems to build nests in enclosed spaces in decks and stuff, but I don't know what kind of hornet those are. Perhaps they would build in a feedhorn, I don't know. But back to the wasps, I generally take the feedhorn cover off my BUD in the summer, because I almost killed myself once when I went up on the top step of a ladder once to work on the feed, took it off to find a big wasp nest inside. Scared me enough that I tried to run, while still on top of the ladder. My feet, and the top of the ladder went one way, the rest of me went the other way, and I fell horizontally 6', hitting a big 4' rock that was next to my ladder. I could hardly walk for weeks after that. After that, I decided to take the cover off, so they won't build in there.