so i've been running a diamond x50 on the roof for a while now, about 50 foot of RG-8X going down through the attic and into the shack. works fine on 2m but i feel like im losing quite a bit on 70cm. been comparing notes with a guy across town and my signal reports on 440 are always a bit softer than i'd expect given the height and location.

i've been trying to figure out if its worth pulling all that coax and replacing with LMR-400 or something comparable. the run isnt super complicated but its not fun either, goes through a couple of bends in the attic and i used one of those right angle adapters at the radio end which i know isnt ideal. probably should have used a proper sweep there but at the time i just wanted to get it working.

anyone done a straight swap like this and noticed a real difference on 70cm specifically? not talking about marginal gains, like actually noticeable on the air difference. the x50 is pointed up at about 20ft agl so im not expecting miracles but i do hit a couple of repeaters that are borderline and it would be nice to nail those consistently.

yeah 50ft of RG-8X on 70cm is definitely costing you. if i remember right youre looking at something like 3.5-4dB loss over that run at 440MHz versus maybe 1.5 or so with LMR-400. thats real, thats not marginal. on a repeater that your barely hitting thats the difference between being readable and being in the noise.

did the swap myself a couple years back, same kind of situation, and the improvement on 70cm was honestly pretty obvious. 2m barely changed which is kind of what you'd expect. if youre going to redo the run i'd also ditch that right angle adapter and just make a gentle loop in the coax instead, those things are lossy and mechanically kind of sketchy long term. LMR-400 is a pain to work with in tight bends but it's worth it, or LMR-240 if you need more flexibility and your run isnt longer than it is.

honestly the right angle adapter is probably hurting you more than people think, ive seen those things measure pretty bad especially at UHF. coax upgrade will def help but id sort that out at the same time or youll just move the bottleneck around.