So i finally pulled the trigger on a FT-7900R and got it mounted in the cab of my F-150 last weekend. Overall pretty happy with how it turned out but i have a couple things bugging me still.

First off the antenna — i went with a Tram 1185 on a mag mount for now just to get on the air while i figure out a permanent solution. I know mag mounts arent ideal but honestly the reception seems fine so far, been hitting all the local repeaters no problem. My question is about the coax routing. Right now im just running it through the door seal which i know isnt great long term. Has anyone done a clean install with a proper grommet through the firewall or somewhere else that doesnt look terrible? I have zero experience drilling into vehicles and im a little nervous about hitting something.

Second thing — the radio is pulling power direct from the battery with 12 gauge wire fused at both ends like i read everywhere to do. But i notice when i key up on high power the voltmeter on the radio dips a little, like down to maybe 13.2 or so. Truck is running. Is that normal or should i be concerned? The previous owner had some kind of aftermarket stereo system in there and i wonder if there might be some other draw happening.

Anyway mostly just excited to be mobile finally. Been operating from home for two years and its a completely different experience, so many more people on during commute times.

Congrats on the install, FT-7900 is a solid radio for mobile use, Ive had one for probably six years now and its been pretty bulletproof.

On the coax routing — yeah definitely dont leave it in the door seal, itll eventually cut through the jacket and then youll have all kinds of grief. What I did on my truck was find the factory grommet where the factory wiring passes through the firewall, there's usually one on the drivers side that already has some slack in it. You can carefully push an additional wire or coax through that existing grommet without drilling anything new. Gets a little fiddly but totally doable. If you want a clean permanent antenna mount look into a lip mount for the rain gutter area or a stake pocket mount in the bed, no drilling required and way more stable than a mag mount long term.

The voltage dip is completely normal, 13.2 when transmitting on high power is nothing to worry about as long as it bounces back up when you release the PTT. Your alternator is doing its job. You'd start getting concerned if you were seeing like 11 something or it was staying low. As long as connections are clean and tight you're fine.

yeah the door seal thing will eventually wear through the coax shield and you might start getting weird RFI or just straight up bad SWR readings and not know why. happened to a buddy of mine took him forever to figure out why his signal was so noisy.

also on the mag mount thing — totally fine for getting started but if you ever notice any flutter or the mount sliding around at highway speeds just double check you have a good ground plane under it. on some trucks the roof has a liner underneath that creates kind of an air gap and it affects the ground. might be fine might not, depends on the spot you picked.

welcome to mobile operating btw, it really does change things. i probably do 80 percent of my VHF/UHF operating from the truck now just during my normal commute