2010 Freightliner Cascadia antenna solutions

Heres the deal on Cascadia's. behind the speedo there is a junction box for the cb and stereo. There is a adjustment for swr on that junction box. Until you adjust the antenna trim you can change antennas indefiately and not obtain a good swr.

 

It cant be the box under the dash. Ive bye past it. I will try the dile pole idea. I have an extra antenna . I just need to find one of the metal bars with the antenna connections on it. We will see

 

Interesting. So if i'm not way off the mark, where I have my antenna mounted on a birds perch off the side of the mirror, I would put a mount as you discribe from the "DIY antenna solution link" on the birds perch and I should be able to get SWR way down?

 

Yessir. The bird perch just simulates a short section of tubing like what would in past years have been a typical mirror mounting frame, except the perch is just long enough to put an antenna mount on. So you modify a mount with an extra hole (it doesn't have to look exactly like my pic) and put the second whip facing downward from the mount. Now you no longer have to worry about whether the mount has a decent "ground plane", because a dipole needs only the actual ground you drive over to "work against".
And no need to come up with an exact duplicate for the "second half" of the dipole. If you've only got room for a 2-ft Barjan CB whip for the bottom part but a 5-ft Firestik on top, that's fine. Don't bother trying to tune the bottom antenna; just tune the top antenna like you would in a normal mobile installation and go for minimum reflected; don't get too hung up on the actual SWR number. Anything less than 2:1 isn't going to harm a radio, the difference between 1.3:1 and 1.7:1 will never make a difference on the air.
But yes, having the dipole rigged at the mount should make it much easier to get a decent match and put a good signal on the air.
Plus it's cheap, which as a ham is important to me -- I've spent a fortune on test equipment, but I use wire antennas, and my newest radio is 25 years old.... I always go for a better antenna instead of more power, and this vertical dipole is cheap and effective. Works great on the perch. Just make sure you've got clearance under the mount, and angle the hole if you need to tip the bottom whip a little.
73,
Handlebar

 

Killer, if you can even just find a mount with the typical single stud on it, but that has room for a second on the same plane, you can just drill a hole and put a second stud on yourself instead of shopping for a specialized dipole mount. There's only one truck stop near where I live, and on the same wall with the antennas there are parts, including studs. So you should probably be able to pick up everything you need in one place, if that's any help. Don't bother with a connector, though. Just get one of the 3/8-24 studs, metal washer(s) as appropriate, and a bolt to hold it from the other side of the bracket. Don't insulate it at all; it's supposed to be common to the ground side of the coax.
73,
Handlebar

 

Like this

 

It is worth trying, don't forget to leave out the plastic washer. I tried it before but never had very good luck with it making an improvement. I tried it on the Cascadia one night too. On the passenger side factory mount, I couldn't get to the factory coax to disconnect it.....might be why it didn't work out for me. I had a set up similar to the one in the picture and bolted it to the factory mount and tried it with two 4.5ft Francis antennas and my own coax.

 

That is interesting, I might have to try it

 

Yeah, it's not going to solve all the problems having to do with placement of the antenna regarding shadowing by the rest of the vehicle and the height of the "upper antenna" and such, but it should at least allow your radio to see a decent 50 ohm load. Although in the example posted by Killer, I'd try to lead the coax away at sorta right angles to the axis of the antennas, like by tie wrapping it to the mirror mount for a little ways. Having it hanging down next to the "down half" of the dipole will do the same thing to that antenna element as having the main antenna next to a stack or a body panel. Sorry, I should have mentioned lead dress earlier. If you've got a 90 degree coax elbow, you can use that on the end of your coax (it has a male and female, just screws on) so you don't have to stress the coax to point it towards the rail that the mount is clamped to, then tie wrap it to there (or something at the same height and close to the cab).
Hope this helps. And ya' can't beat the price if it does
Handlebar

 

I will tie the coax. But atlast still high swr. It cam down a lottle. But still high.