New CB Problems

http://www.rightchannelradios.com/outback-mount-for-kenworth-t2000-peterbuilt-387.html

is this the mount you purchased?

 

the bracket i posted is the one you should really be using. the problem with the spot you have is there is just too much of the antenna that is facing the back of the truck and trailer when coupled. that is bad for reception and well bad for transmitting too. all of your signal is bouncing back and forth and not really going anywhere. the biggest thing is not being able to hear what is down the road waiting for you.

i understand that some drivers are limited with funds for radio projects, so sometimes you are forced to do what you have to do. but if you can, i would seriously check in to changing your antenna location and try to get one of those mounts. you will notice a big difference.

 

WCM,
Perhaps I can help a little. Some of the ideas already posted have merit.
Before you go looking for a "resistor" for the alternator, ummmm.... in a word, *don't*. My suggestion about alternator noise is to see if you're receiving it through your power lead or your antenna. That's easily accomplished by unhooking your coax at the radio end and seeing if all the alternator noise disappears. If it does, then the noise is being transmitted like a tiny radio signal, through the small distance from the alternator to your antenna, and being received by the CB. The only sure way to kill that is a gen-u-wine PITA, and that is to shield the alternator and the wiring associated with it.
If, by happy chance, the noise does not go away, then you're receiving it through your power lead, and for that you can either buy or build a DC power line choke. It's easy to build one with an iron Quik-link or shackle, some 10 or 12 gauge wire to wind on it, a capacitor from Radio Shack ("Radio Shack: You've got questions, we've got blank stares!") and a box to put it in. Here's a link to the plans. Just remember to choose a wire gauge suitable for the current draw of the radio you're going to run off of it:
http://www.worldwidedx.com/home-brew/31492-building-simple-alternator-whine-ignition-filter.html

As for antenna grounding, remember that what you're trying to achieve is an RF ground plane, *not* just a DC ground. You're trying to simulate what, in a perfect world, would be a really large, flat metal surface, like a trailer roof, to serve as the "other half" of your antenna, the part that the shield of your coax is connected to. If you've got several metallic masses that are fairly close to the antenna's mount, run a ground braid or strap to all of them if it's practical. It's better to have lots of short grounding jumpers than one long one. They don't even all have to be the same length.
It's even possible to have just one "ground lead" of such a length that it will be of such a high impedance that it will seem to "disappear" to the system, and will not function at all.
BTW, an SWR of 2.3 means you're only losing about 15% of your power. To someone receiving you, that's less that the width of a needle on an S-meter, and nobody will hear the difference. I noticed when you took your test drive on I-270, it sounded good. If you can combine your current mount position with what Rat suggested by getting the tip of the antenna as high up as you can without getting it sheared off by overpasses & stuff, AND shorted any excess coax you have (if there is any after all that routing you had to go through), I think I'd go with that. You can also check your SWR with an 8 or 10 foot jumper, standing on the ground with your CB running on a power pigtail so you don't have all that loss and "artificial SWR" given by the long coax itself. Then, once your antenna is tuned, hook up the "real coax", jot down the SWR as shown, and just remember that as what it shows when it's "normal". A really long coax can mask a world of faults, all by itself.
It's unfortunate, but all too often, particularly with the increasing use of lightweight use of synthetic materials to save weight (and therefore fuel), we're losing radio system efficiency, so it ends up being harder to achieve resonant antennas that also present a good SWR at the radio. And it's gotten much harder to make a system that also looks nice. There's a temptation to use higher and higher power to make up for the low antenna system efficiency, but a bad antenna receives just as badly as it transmits, so even though receiving doesn't perceptibly heat up the coax, a lot of the incoming signal is still lost before it ever gets to the radio's receiver input.

As for antenna pattern symmetry, it's not going to make too much difference where you mount an antenna in real-world conditions. Sure, you can graph it out, and show where the major lobe of a pattern *should* be, but you're also not firing a laser in a vacuum. Radio waves diffract around obstacles, and they only really reflect in substantial values from surfaces (like trailer fronts, etc.) at predictable fractions of a wavelength. But even then, you'll stil be heard to the rear. Most real-world patterns are only noticeable at the very fringes of range, where the last gasp of a signal is barely making it into someone's radio, and *then* you might get a little change by turning your rig. But I've been using steerable arrays at VHF and literally bouncing signals off the moon and back to others on Earth, where a little bit of aim makes a big difference (and so does every last fraction of gain in a bunch of stacked antennas) and I've found that as I go lower and lower in frequency, it makes less and less difference. Below 30 mHz is pretty low indeed.
Dunno if that helps or not.
73,
Handlebar

 

I just ordered a new antenna and ordered 15' the guy called me on my cell and told me I must use 18' I know I don't need anything near that amount I bet 12' would do . So whats up????

 

There are only a couple of times you need 18 feet of coax. If you're using an antenna that's designed to be used without a ground plane, there are two main ways to accomplish it: either you can center feed a helically wound vertical dipole, like on a Shakespeare marine CB antenna (you can see the coax enter the hollow fiberglass mast near the bottom), OR an antenna can have a transformer at the base, and then use a measured length of coax to add enough reactance to the feedpoint so that the overall impedance at your radio's end of the coax is close to 50 ohms.
Otherwise, the theory is that if you can *precisely* calculate, cut, and terminate (install connectors) on a piece of coax for one frequency (really, only one or two adjacent channels), a half wavelength of feedline will show the SWR at the radio end the same as it is at the feedpoint at the antenna. But go 20 channels away and you'll be far enough out of the calculation that the length will no longer be precise.
That's why it's best (for a single antenna) to just use the shortest piece of coax that will reach from your radio to your antenna. Assuming you don't have access to an antenna analyzer to discover the actual frequency at which your antenna is resonant, just use some random length of coax and tune for the lowest SWR. Your goal is to have the lowest amount of energy reflected by the antenna. The actual value is kinda just for bragging, since most people really don't have the equipment to accurately measure it with.
When I do an install, I leave about a foot of spare at each end. Eventually, the connectors will likely be taken on and off enough times by people who need to move things for washing, or swapping and testing, and at some point one connector or the other will fail. I like to have enough slack to insert a meter if needed, and be able to put on a new connector or two over time as needed. But the difference in signal level between 10 feet and 20 feet at 27 mHz with any coax from RG58 and larger won't make any difference that anyone can measure. Even the pre-made low loss cable kits that I use for VHF and UHF installs typically have 17 feet and are designed to be mounted through either the trunk deck or the roof, then get routed to the dash. There's usually only a couple of feet left, and most techs leave it under the carpet so it's available later if needed.
On the other hand, people who sell coax from a 500-ft roll typically sell it by the foot, so you be the judge. Billy Ward (RIP), who was one of the folks who used to be known as the CB Doctor, had a lot of good knowledge, and a cute little applet on his web page. It was his "coax length calculator". You'd put in your "distance from radio to antenna" in a little box, and hit the "Calculate" button, and the "Coax length needed" window would give an answer.
It wasn't coincidence that the answer always exactly matched the distance from radio to antenna entered by the person using the calculator.
So, Mt. Airy, unless you're ordering either a no-ground-plane antenna kit, or a pre-packaged antenna in a blister pack, I'd call someone else. Or just smile to yourself and figure you've got three feet of slack in case something goes wrong with one end of your install and you need to cut off the connector and re-do it
73,
Handlebar

 

The factory coax probably go thru several junction type boxes causing you to lose signal/power. Replacing the factory coax with some good coax and going direct to the radio, would probably make a world of difference and together with some quality antennas, would probably work real well for you.