so ive been running a Diamond X510 collinear up on a hilltop site for about two years now for local 2m/70cm work and it does the job fine for everyday repeater stuff but lately ive been wanting to work some simplex farther out, like 80-100 miles on a good tropo day, and im starting to wonder if swapping to a yagi or even a dual-band yagi like the Directive Systems or Arrow stuff would actually make a meaningful difference or if im chasing ghosts here.

the X510 is up about 30 feet on a pushup mast with LMR400 running maybe 60 feet to the shack, so the feedline loss isnt terrible. im running about 50w on 2m from an IC-9700. the location already has a pretty clean shot in most directions except there's a ridge to the north that kills anything past about 40 miles that way, everything else is pretty open.

main question i guess is whether the gain from a yagi actually translates to real world improvement on tropo or if the collinear is already doing most of the work and im better off just leaving it alone. i know the obvious answer is 'yagi wins on gain' but im wondering if anyone has actually done this comparison from a similar setup and noticed a real difference in practice, not just on paper.

yeah it absolutely makes a difference, done this exact swap actually. had a M2 2MCP14 sitting in the garage and finally put it up alongside my vertical last spring just to compare. on flat calm tropo days the yagi was pulling in stations that were completely in the noise on the collinear, like stations i didnt even know were there. the gain difference is real but honestly the bigger thing is the front to back ratio — you cut out so much of the local QRM and that alone opens up weak signal stuff that the omni just buries.

the downside is obvious, you gotta point it. if you want to work in multiple directions you either need a rotator or you're constantly going outside to turn it by hand which gets old fast. i ended up putting a small TV rotator on mine just for the hilltop experiments and it works fine for light duty use. if you're serious about tropo though the yagi is the way to go, no question, the collinear is great for general purpose stuff but its not really a weak signal antenna.

not to derail but whats your coax situation at the hilltop, is it weatherproofed well? asking because i had an X500 that looked fine for a year and then i started noticing weird SWR readings and turns out moisture had crept into the connector at the antenna end and was just slowly wrecking everything. ended up with like 3dB extra loss i didnt even realize i had. self amalgamating tape and then regular electrical tape over it made a huge difference once i resealed it all. just something to check before going down the yagi rabbit hole, make sure you're actually getting what you think you're getting out of the current setup first.