so ive been running a Diamond X50 on the roof for about three years now and its been fine, decent coverage on the local 2m and 70cm repeaters, nothing to complain about really. but i picked up a used 2el yagi at a hamfest last month, M2 i think, and got to thinking about whether pointing it at the main hilltop repeater 40 miles out would actually make a noticeable difference or if im just chasing gain numbers that wont matter in practice.

the thing is the repeater is basically due west of me and i dont have much to the east anyway so rotating it probably wouldnt be an issue. my concern is the vertical polarization thing — i know yagis are usually horizontal for weak signal work but most repeaters around here are vertical. i've seen people talk about orienting the yagi vertically but then the boom is horizontal and it starts getting weird with mounting. anyone actually done this and was it worth it over just leaving the collinear up?

also wondering if theres a point where the collinear just wins because of the wider pattern for mobile stations checking in. the yagi would obviously null out anything behind it.

yeah i did exactly this a few years back, had a vertical yagi pointed at a repeater about 35 miles out on a ridge. the gain difference is real but the pattern issue you mentioned is the actual tradeoff — i missed a bunch of nets because guys were coming in from directions i wasnt expecting and they were like 20 over on the collinear but barely readable through the yagi. ended up putting both up on the same mast about 3 feet apart and switching between them depending on what im doing. coax relay from an old rotor controller box, works fine. if you mostly just want that one repeater the yagi is genuinely better but if youre doing any kind of ragchew where mobile stations are coming from all over its a pain.

the vertical orientation on a horizontal boom is not a big deal btw, just mount the boom horizontally and the elements are vertical, people overthink that part. the feedpoint is the feedpoint regardless of boom orientation.

i cant really speak to the yagi side of things but just wanted to say the X50 is a solid antenna and you might be surprised how much you can get out of it with a better feedline if youre not already running LMR400 or similar. i upgraded from RG8X on mine and it made more difference than i expected especially on 70cm where the loss adds up fast. 40 miles to a hilltop repeater on 2m isnt that crazy for a decent collinear if the path is clear, whats your terrain like between you and the site?