Antenna question

I know that a longer shaft increases the electrical length of the antenna, but I was wondering if I could use a really long shaft with a base loaded antenna and trim the whip down to a reasonable swr without adversely affecting the performance of the antenna.

This would be done on a truck, I just want to get the load a little higher and away from the truck, president radio and antenna with an amp, 9ft coax with 3 foot jumper. If it's not a feasible idea then I'm going to just get a fiberglass "top" loaded one.

Thanks in advance @rabbiporkchop and @Ridgeline

 

That's what my reasoning was, if I get the load and by extension the entire antenna higher I would have better performance. I just have to find a shaft that long somewhere, they don't seem to be very common.

Are there any problems that might arise from doing something like that?

Edit: found some at Walcott online.

Edit: guess I'll measure it up to see how long of a shaft I can actually use.

 

Thankfully I'm not mathematically retarded, so my current plan is to start at 14' for the overall height because I'm not sure how much of the whip will need to be trimmed and I should be fine even if it's not very much. I'm using rg8x for the coax so I won't have a lot of loss, and using the longest shaft I can, which means I could wind up trimming quite a bit out of the whip. We'll see how it goes, I'll stop somewhere and use an antenna analyzer for the set up once I run the cable and power cords.

Believe me, if I could just get do whatever I wanted to the truck to get the best setup I would, unfortunately I'm stuck with the stock configuration of the company truck.

 

T680 unfortunately with studio sleeper.

Edit: I pull flats so if it wasn't a studio sleeper it would be a lot better for radio.

Edit2: and aerodynamics, and looks, and storage space, but whatever, I didn't pay for it haha.

 

Run it through the existing coax path from the mirror arm to the gasket in the frame that goes through the fuse box area then up the side and upper interior panels to the factory radio bin.

The mount on the mirror arm has a 90 degree connector, I'll probably replace it and the stud if possible. I haven't taken the mount apart yet to see, but make sure you sand off the powder coat underneath and run a ground strap to where the mirror arm connects to the door.