DIY antenna solution for fiberglass cabs

Sounds real good and I can hear a lot better. I'm not sure that spring is heavy enough. I haven't run with it yet and it might just lay over on me. I'll find out when I hit the highway tomorrow. I'm zip tying the whole thing to the mirror mount in case something breaks.

Still have to scavenge more parts to do the other side and hook up a real SWR meter to see how it does.

 

That looks like a heck of a setup. What brand and length antennas are you running? And how did that spring hold up for you?

 

Not that you have much choice, but does the closeness of the mirror arm to the lower antenna screw things up?

 

Nope, there's plenty of clearance and room for adjustment. Those are 5 foot wilson 2000's on top and two foot wilson 200's on the bottom. Haven't taken off yet to see what the spring does.

Here's some different angles.

 

Yeah, this spring isn't heavy enough. Have to find a bigger one.

 

OK from those pics I can see it isn't that close, from the side it loked kinda different.

I've never had luck with springs, or foldover antennas that are supposed to give if you hit something. If you are doing 75mph in Wyoming and get any of their normal winds, it's easy to get wind loads greater than 100mph, which nothing I have seen so far seems to be able to handle.

 

That's what I was thinking. I'm going to the thickest one I can find. The antenna already leans a bit in the wind due to how long it. I don't need the spring to lay over at all. It's just there to put some give in the brackets so they don't break when I hit a tree limb. I already hit one on the other side and it broke the stud. Didn't hurt the antenna at all.

 

After reading this through, thanks to all of you for the info and explanations. My question is whether a standard split twin mount on a modern truck are wired separate, or are they wired like these are, just in 2 separate mountings?

I've been trying to figure out the twins on my 780 for a couple years. A previous driver ran a length of decent coax to one of the factory antennas and I've been using that. One night in a contruction zone I was able to talk and receive to a driver over 10 miles from me, with only a tuned Cobra 29. I never thought a stock single antenna would do that well, and he could hear me fine over everyone else in the area.

I've kept myself from buying a better antenna, because 10 miles and clear seems good enough for my purposes. It also has some kind of mobile phone antenna connector under the dash that I understand has space on the stock antennas as well - but I always used a separate antenna for my phone/ internet.

 

You don't really gain a whole lot with "twin antennas". First off to work at peak performance they need to be 12ft apart and they aren't quite that far apart. Second your range will not change. Your pattern will change and you will get out further in one direction over a single antenna, (mostly out to your sides) but there is no real compelling reason to run two antennas other than looks. Your coax must be co-phased to run two antennas. Most drivers don't go with two antennas after the original equip. wears out. More trouble to tune and keep tuned and more expense with very little noticeable gains.

Can't figure out why "kajidono" used a spring. Why drop the mount down from the bracket that is attached to the mirror arm? I've built and tried several different "counter poise" antenna systems. They are not a cure all, sometimes they work and sometimes they don't. You guys that are changing from the "factory crap", i.e. am/fm/cb antennas, and coax that runs thru several junction boxes, will notice a huge improvement in your receive by going to a dedicated coax and antenna. It might even talk better/farther. A radio set-up with a dedicated ant. and coax, with a 3:1+ SWR will work better than the factory crap on a new Freightliner! (I know cause I've tried about everything on one.) But your finals are not gonna last long with 3:1+ SWR.

 

I said why. I do not want to put in all this extra work and money just to have it destroyed by the inevitable tree branch. No particular reason I went down. I can easily flip it around and go up. I'll have to see if that makes any real difference.