wilson 5000 question

You can, I have seen it done. However, the Firestik is a better option for that, because it is a top loaded antenna, and the the top of your antenna is going to have the least interference with your vehicle. The Wilson is a base loaded antenna. With that base coil being so close to the cab & tool box, your SWR will be much higher. That Wilson is better off on the roof.

 

I would go and purchase a FRANCIS antenna, there cheap and out performs the firestick.

 

Whichever antenna you choose, the higher up and more "in the clear" that you can mount it, the better it will work. One of my two rooftop antennas is a PCTel/Maxrad MLB-2700S, it's base loaded on a 3/4-inch "NMO" hole mount (easy install, fish the line down the pillar behind the door). It's got a stainless spring and a 48-inch stainless whip. It works a little better than the 2-ft Barjan top loaded fiberglass whip that goes on the same mount with an adapter for the threads, but the 4-ft Barjan top load fiberglass on the same mount works best of all three.
What the other gentleman said about the position of the loading coil is correct. The Maxrad is the most forgiving of physical abuse, and thus is the choice of many public safety and utility agencies. The cable is internal to the vehicle body, the mount is wide and low, the coil form is lots of brass and Cycolac and Delrin plastics, and everything up higher is really tough and flexible. You can hit low tree limbs at substantial speed (I've done it with emergency vehicles at my old job) and never know it. Any of the fiberglass would have been turned into roadside litter by then. But there's a slight loss of radiation pattern effectiveness to the base load style.
The fiberglass antennas are measurably better, but not practically so. By that, I mean that I can measure the difference on a test range, but the performance within under 10 miles is not noticeable. If you always need to talk out to the absolute farthest you can, I'd go for the fiberglass. Also, the fiberglass is better able to stand upright when you're moving, helping keep its pattern parallel to the earth. Steel whips bend back, skewing the pattern.
My understanding (open to correction, of course) is that the Wilson 5000 (made much like the Maxrads, BTW) can be taken off the magnetic mount and fastened to a permanent roof mount.
Since you've already got the expensive part, my vote would be to go for a permanent roof mount for the Wilson, if there's any chance you'll be hitting things with an antenna that's four feet taller than your roof. If there's no chance of that, and you always need the farthest talkout range you can get, putting a beehive permanent roof mount with a 3/8 x 24 thread will let you use different length fiberglass antennas as space and budget permit.
As for brands, everyone has favorites. If one brand of antennas were superior to all the others, there'd be only one.
After an antenna is tuned in an installation, it shouldn't have to be re-tuned *ever* unless its surroundings change (camper, roof rack, etc). If SWR changes after initial tune, something in the antenna system has failed, and no amount of tuning on the antenna will fix something that's broken. Length of an antenna that's otherwise tuned correctly, when compared to longer or shorter versions of the same antenna, will affect the usable bandwidth (i.e., how many channels it can cover) before the SWR goes unusably high at the edges. My 2-ft Barjan does fine for the regular 40 CB channels.
Hope that helps,
-- Handlebar --

 

Jeff,
How much taller then the bed rails is the top of the cab? The cab will shadow much of the signal towards the front, basically any direction from which you can stand and not see the whole antenna. The more of it you can get higher than the cab roof, the better. Signal towards the rear will be better than towards the front. You'll also have a skewed pattern that's weaker towards the same side as you're mounted on, that is to say, if you mount on the left rail, you'll have a considerably weaker signal to the left of the truck than to the right.
Since the level of the rail is way above the truck bed there will be some decoupling, or loss of continuity, between the point the antenna treats as its RF ground and the greatest surface available to work as ground plane. The rail will function somewhat, and down the sides of the bed. Be sure to bond things, as you mentioned: body to frame, body to cab, exhaust system to body, etc., to reduce sources of noise and enhance the RF ground system. Also the tailgate to the bed, and the stake mount to the bed. If you don't already have some large braid, you can strip the center out of some RG-8 coax and use the braid from that, flattened, as grounding braid.
Will that 5.5' whip have at least 4' above the cab, do you think? Also, some fiberglass whips are center loaded, some are top loaded, and some are "continuously loaded". The packaging will usually say which they are. The higher the load, the better. Continuously loaded means a fairly even pitch to the wire wrapped around the glass core. You can look at most whips and see the winding, and see where it goes from looking like an augur and changes to closely spaced wraps. The loading coil is the closely wrapped portion. Some manufacturers load the antennas a little way down from the top, or as much as 18" down, so that there's a VHF-equivalent portion at the top for CBs that have weather receivers built in. A top loaded antenna will pretty choke off any VHF reception, although most NOAA transmitters are between 300 and 1,000 watts, so if you've got line of sight to one of their sites, even a crappy VHF antenna will still hear them.
So, duzzat help, or did I make it worse?
-- Handlebar --

 

Jeff,
Geez, that's a tough call. The K30, despite its pedigree, is kind of a marginal performer in my experience. They're durable enough, but in side-by-side tests I've done with other magmounts, I found them to be less tolerant of wind or bumps (likely to lose their grip), and they're quite narrowbanded. I couldn't get an acceptable SWR across all 40 channels, even over an adequately large groundplane. And radiated signal, compared to other base loaded antennas, was lower when using equivalent coax and the same radio as a test source.
Unless you're in a hurry, and if you've got any of the antennas you've mentioned already, it would be worth testing what you have.
Figure that *anything* on the roof will have a nearly symmetrical radiation pattern, as well as having the built-in height advantage. If you've already got the Wilson 5000 magmount, try it on the center roof versus sitting back on the rail near where you'd be putting a stake mount. Also try putting it on the hood at the edge, on the opposite side from where the be-bop radio antenna is, to simulate a hood edge bracket.
Those trials will give you an idea of the relative merits of different mounting locations using the scientific method, wherein you change only one variable at a time. It may turn out that, for your needs, all positions are close enough to the same as to be equally usable. In that case, unless you're running a diesel engine, I'd opt for a position on the rear of the roof, or the bed rail; the farther from your spark plugs, the quieter your receiver will be when the engine is running, or the wipers, fan motors, etc.
And as for holes: pulling the load light out can give you good access to the underside of the roof at the centerline, and a neat antenna install can always be covered up with a rain cap, or a hole plug, or leave an antenna on if you go to sell the truck. It might even be a selling point, especially for a 4x4 with a lift kit in it, if it's intended for actual off-road use.
If you do decide to opt for the roof, please remember to bond the doors to the body near the hinges, too, because the doors will serve as part of the ground plane.
And regardless of where you end up putting the antenna (including during any magmount tests) always close all doors, hood, and tailgate to make as complete a RF ground system as you can. It's tempting to leave a door open and just lean in to check the radio.
-- Handlebar --
P.S. I'd take a 5000 on the roof over anything on the bed rail, if that's what you really wanted to know. A tall glass whip on the rail vs. a K30?
Dunno; probably the glass whip on the rail.