so anyway after about three weekends of messing around with cable routing and figuring out why my SWR was all over the place i think i finally have a decent setup going. running a Yaesu FTM-400 in my F-150, antenna is a Diamond NR770HB on a mag mount for now until i get brave enough to drill through the roof.

the big thing that was killing me was the power cable. i had run it through the firewall but i was tapping into a fuse block under the hood instead of going straight to the battery, and apparently that was introducing enough noise to drive me nuts on receive. switched to direct battery connection with an inline fuse and the difference was honestly night and day. i can actually hear the repeater now without that buzzing behind everything.

also the mag mount placement matters way more than i thought. had it on the rear corner of the roof at first and was getting a ton of multipath garbage on 70cm especially. moved it closer to center and things cleaned up a lot. probably still gonna drill eventually but wanted to get a feel for the radio first.

anyone else run that Diamond antenna? curious how people like it long term, specifically whether the SO-239 connection at the base holds up or if it gets flaky over time.

yeah the power cable thing gets almost everyone the first time. ive seen guys chase RF noise for months and it almost always comes back to either a bad ground or not going direct to battery. the alternator whine is the worst, especially in newer trucks with all the electronics they cram in there. glad you got it sorted.

as for the Diamond antenna, i ran one for about two years on a chevy colorado and the base connector was totally fine, never had any issues with it getting loose or corroding. what i did do was put a little dialectric grease on the SO-239 after i first put it together just as a precaution. probably overkill but it made me feel better. only reason i stopped using it was i finally drilled the roof and went with a lip mount, which is a good middle ground if you dont want a hole all the way through the sheetmetal.

this is really helpful actually, im in almost the exact same situation — just got my tech license last month and im trying to figure out my first mobile setup. didnt realize the power connection made that much of a difference. does it matter how long the cable run is from the battery or is it more about where you tap in?