T680 Antenna setup help

24 feet of rg158 or rg213 @ 27.205mhz

 

Most of the guys are using 27ft on the Freightliner Cascadia.

 

Make a bracket that can bolt into the stock antenna stud location. Run a vertical dipole (eliminating the need for grounding) on said bracket. I've seen this done on T600s and T660s as well.

 

that's sad to hear about the 680's antenna issues. I remember the 660s had some of the best stock setups I ever used.

 

I have use 30FT on similar set up, and i had to use ground strap from headache rack to frame, because my rack was sitting on rubber pieces.

I was using a predator top at 13.7 and did talk all over the world with that set up.

Good luck

 

I checked out the T680 the other night. With the stock antennas the SWR measured 2.6:1 on ch. 19. Flipped down to low 19 (26.735) and it jumped to over 3:1. Installed two 4.5ft Francis antennas. SWR did not significantly change. Installed 5ft SkipShooter on the drivers side and the SWR dropped to 1.6:1 on ch 19. I forget what it dropped to on low 19 but it was a 2.low number:1. It did not make any difference on the passenger side if I used the 4.5ft Francis or the stock antenna in conjunction with the 5ft SkipShooter. I'm thinking two 5ft or longer SkipShooters would be ideal as far as having a good SWR. I'm thinking they would be even better than the 5.5ft Francis antennas because they are top loaded. Anyway, longer is better as far as SWR goes on the KW T680 I checked. (I checked SWR on another truck and it was about the same but I didn't try swapping out the antennas and rechecking.) As far as performance goes. That is a test for another day. I'm not expecting much because of all the splitters in-line on the coax.

 

Mike5511, when your SWR reading is over 3, that is a dead giveaway that your antenna ground plane is the problem. Sorry, changing antennas is not going to solve the problem. When you have splitters inline, every connection reduces your power going to the antenna which is another problem altogether.
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.If it were me - personally - I would run just one antenna on the drivers door. I would then skip the original coax entirely and run my own short length of 50 ohm coax. All I need is a couple of feet of coax. Since I absolutely hate with a passion running coax, I would run it through the driver's window and up to the radio. That may look like hell but I do not care. Hey, it is a temporary setup for now.
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. I would also install another antenna mount and antenna with the antenna pointing toward the ground. That should fix the antenna ground plane problem. It also drives the other drivers crazy because they think that antenna is going to fall off the truck.

 

Mirrors arm powder coated=very bad ground...I had similar issue with T600.