so ive been running a mag mount dual band whip on the truck for about two years now, nothing fancy, one of those cheap diamond knockoffs i picked up at a hamfest. works fine for most of the repeaters in my area but theres one about 65 miles out that i can hit from the hilltop near my house when im walking around with the HT but cant seem to reach reliably from the truck even though id expect a 50w mobile to do better than 5w handheld.

got me thinking about whether a small 3 or 4 element yagi mounted on the roof rack would be worth messing with for that specific path. the repeater is roughly to the northeast of me and i mostly drive that direction anyway for work so it wouldnt be like im always pointing the wrong way. but then again a yagi on a roof rack with no rotator is basically just a fixed direction antenna and id have to physically turn the truck which is kind of stupid.

maybe a better collinear would close the gap instead? i know gain figures on those cheap whips are basically marketing nonsense. wondering what people who actually run decent mobile setups think about this.

the collinear route is probably more practical for a mobile install honestly. a properly made 5/8 over 5/8 colinear will give you real measurable gain over a 1/4 wave and you dont have the directional problem. the cheap mag mounts usually have terrible ground planes and lossy coax too so theres a lot of low hanging fruit before you start bolting yagis to your roof rack.

that said i ran a 2el tape measure yagi zip tied to a broom stick on my rear window once just to hit a distant repeater during a road trip and it actually worked great for that specific use case lol. but yeah for everyday mobile use get a decent antenna with a good mount, run LMR-400 or equivalent to the radio, and make sure your ground plane is solid. that alone might solve your 65 mile problem without doing anything exotic.

what coax you running to that mag mount? because thats where i'd look first. those whips usually come with RG-58 which at 2m is gonna eat a couple db before you even get started, especially if the run is long or its an old cable with any moisture in it. i replaced the coax on my setup and it made a noticeable difference on marginal paths.

also where exactly is the mag mount sitting on the vehicle matters a lot more than people think. dead center of the roof is ideal but most people stick it wherever is convenient and then wonder why the pattern is messed up. anyway worth checking those basics before spending money on a new antenna.