so ive been running a diamond x50 on my roof for a couple years now and it hits the local 2m and 70cm repeaters just fine, maybe 90% of the time. but theres this one machine about 34 miles out that i can only barely scratch on a good day and it drops out whenever theres any kind of weather moving through. been thinking about throwing up a yagi pointed that direction but then i lose the omnidirectional coverage and id have to manually rotate or put up two separate antennas which honestly sounds like a pain.

the other option i was reading about is going to a longer collinear, something like the diamond x300 or maybe one of the comet GP-9 types, more gain in the horizontal plane, still omni. but ive also read that higher gain collinears can actually hurt you on closer stations because of the compressed pattern? like the radiation angle gets too flat and you lose stuff thats not perfectly on the horizon. my house is in a bit of a valley so i dunno if thats gonna be a real issue or just theoretical.

anyone actually done a back to back comparison or switched from one to the other and noticed a real difference, not just on paper

yeah the pattern compression thing is real and its not just theoretical, especially if you're in a valley or have terrain in the mix. i went from an x50 to a GP-9 and honestly for the repeaters that were already solid, no real change. for the edge cases it helped maybe a little but not dramatically. the bigger variable for me ended up being coax — i had like 40ft of RG-8X which was fine but when i swapped to LMR-400 for the run i noticed more improvement than from the antenna change.

if that one repeater 34 miles out is actually important to you, a yagi on a cheap tv rotator is genuinely not that bad. i did that setup for a while, pointing at a linked system, and it worked great. pain to set up initially but once its done its done. just gotta commit to the feedline going to the rotator which adds another connector point to keep sealed.

34 miles on 2m with a collinear and 50w should be doable most of the time unless theres a real obstacle. whats your coax situation and how high is the antenna? that stuff usually matters more than which collinear you pick tbh. i spent way too long agonizing over antenna choice when my actual problem was a bad PL-259 at the radio end that was adding like 2-3db of loss i didnt know about.