so ive been running a diamond x50 on the roof for a couple years now and its been fine for local stuff but im finally trying to put up a proper yagi for 2m weak signal work, maybe eventually EME but lets not get ahead of ourselves. the run from the shack to the roof is probably 60 feet, maybe a bit more, i havent actually measured it properly. right now theres a run of RG-8X up there which i just used because i had it lying around when i put the collinear up.

my question is basically how bad is 60ft of RG-8X at 144mhz and is it worth replacing before i bother putting up the yagi or should i just try it first and see what the numbers look like. i have a buddy who keeps telling me LMR-400 is the only thing worth running but that stuff isnt cheap and id have to rerout the whole run probably. the current cable goes through a vent which is kind of a hack job anyway so maybe this is the time to do it right

also wondering if anyone has opinions on the M2 2M5WL vs the longer 9 element yagis you see from various makers. trying to stay reasonable on boom length since i have a small roof and my wife already has opinions about the x50 up there

RG-8X at 144 is going to cost you somewhere around 3-3.5 dB per 100 feet from memory, so your 60 foot run is probably eating close to 2 dB. that doesnt sound like much but on weak signal work it absolutely matters, youre basically cutting your effective power almost in half before it even gets to the antenna. LMR-400 is closer to 1.5 dB per 100 at that freq so yeah you'd recover a meaningful chunk. its not dramatic but for EME every tenth of a dB people obsess over so.

honestly if youre redoing the mount anyway just do the coax at the same time, the annoyance of doing it twice later isnt worth the savings. i ran LMR-400 equiv (the times microwave stuff, cant remember the exact designation) on my 2m yagi run and it was totally worth it. the connectors are a bit of a pain to work with compared to thinner coax but you get used to it.

cant speak to the M2 specifically, mine is a homebrew 9 ele but the M2s have a good rep on the weak signal nets i follow. boom length matters less than pattern and feed quality imo.

yeah just do the LMR-400 run now, future you will be annoyed if you dont. also check your connectors because i had a situation where i was blaming coax loss for ages and it turned out one of my PL-259s had a cold solder joint that was adding like another db of garbage on top of everything else. drove me crazy for weeks