http://www.walmart.com/ip/Cobra-Mobi...ntrol/11974001

talked a buddy into selling me his cb. Got it for 50 bucks I think I did pretty good the link above is to what im getting.

Now tomorrow i'll be heading to loves truck stop to pick up an antenna and some mounting hardware and maybe some coax cord. And suggestions on what length I should get? Im running it from the bedrail on the drivers side to somewhere around the driver seat in cab. Ha I still have not fully decided on a location.

 

Cophasing antennae can add gain but also add dirctionality which can be a bad thing depending on intended usage and that is only if correct E/M theory is being properly applied. The problem is most passenger cars/pickups are too dimensionally small to get any directionality making it useless other than for cool factor. Some big rigs are big enough with the towing mirrors to get noticeable dirctivity/gain changes by cophasing. One might argue that enhanced directivity for a long hauler usually going in same direction makes sense. For offroading it seems worthless if you asked me even if you could physically pull it off on our relatively electrically tiny (per CB band wavelength comparisons) vehicles.


5/8 wavelength is very nice indeed but man even a quarter wave on my jacked up rig is a pain. Those Wilsons seem a fair compromise though IMO.

It's true. No coax you can buy or build is ideal and are therefore truly part of the antenna. Use it or lose it.

I actually do pretty well with my 1/4 wave as compared to local enthusiast base station performance comparisons I've made by seat of the pants dynoing. Since I don't have it mounted dead center of cab as ideally would be I'm sure I'm getting lopsided pseudo omni pattern but it hasn't been noticeable or a problem fr me. The hardest but often funnest and most rewarding part of an install for me is usually the noise hunt. Seeking noises is where I always learn new and interesting things. The hardest simple concept to explain to smeone is what a single point ground is and can do for a radio station....even some of the old dogs unfortunately and I've made my share of mistakes for sure.

 

Not to be contrary, but:

There will be real, measurable directionality whenever two radiant elements are more than about 1/8 wavelength apart. In short: If the two elements are 1/2 wavelength apart in space and radiating perfectly in phase you have broadside array that directs power perpendicularly to the plane of the two elements; if those two elements are radiating 180 degrees out of phase, you have an endfire array that transmits on the plane of the two elements. Anywhere between those two conditions, your beam shifts in accordance with the relative phase angle difference between the two elements. Varying the separation in space, the relative phasing of the elements, or both, necessary must steer the beam. Adding more elements to the array increases its focus.

1/2 wave separation in space is ideal, but 1/4 or more will work albeit with a wider, sloppier beam pattern. You can get 1/4 wavelength of separation on a full-size passenger vehicle, and right next to 3/8 on a big rig, so beam steering must be happening with a co-phase setup.

Irrelevant related trivia: my favorite big array is the AN/FPS-85 Phase Array Spacetrack Radar. It's not as advanced as more modern phased arrays, but it's the one I maintained for three and a half years when my hair was cut short and I wore green to work -- and it still had the missile warning mission, too.

The only time the beam pattern of a co-phase on a vehicle might be important is if you find yourself stuck out in the boonies beyond cell phone signals, and can just barely get one operator above the grass in your CB. Then taking advantage of the radiation pattern can be a life saver, or at least save you a long walk out. A good RF pre-amp and an illegal power amplifier would be better choices, not that I'd ever recommend that anyone break the law by adding a power amplifier.

Especially not to diesel dummies who insist on running a couple hundred watts (and echo boxes and roger beeps, with their power mics cranked up to 50% overmodulation) to talk to each other across a half mile of pavement.

 

I don't mind if your contrary. I'm always up for some radio hardware chat. You seem friendly enough about it.

I'll apologise for my cynical attitude in the face of not ever having experimented with cophased antennae enough to be an actual authority of some level.

On my Dodge even if I went bed rail to bed rail I can only get about 5 and a half feet max. I don't have any of those big oldschool girder framed towing mirrors hanging off of there to mount onto. 5 and a half feet is closer to an 1/8 wave than 1/4. All I'm saying is most passenger vehicle users aren't going to get much out of it. I could see an argument for emergency use if I thought what I had could be set up to yield actual nticeable performance differences. I gotta say I'm still skeptical. On the other hand I'd also wager 90% of so called cophase installs are more about sweetly accesorized trucks more than enhanced RF performance but perhaps I'm underestimating my fellow CB'ers.

BTW obviously adding hoppped up preamps on the recieve isn't going to get anyone in trouble but is it still ilegal to put an RF amp on the output even if it isn't powered up? Say so you can run it in passthrough mode and turn it on for emergencies only.

I also have a general distaste for those who choose to overmodulate their voices. With all the tomfoolerey in the CB bands it's no wonder we are considered outcasts as radio operators not worthy of anything over 5W. However, 5W done well is sure a lot better than 5W done not so well and can actually be pretty useful.

 

No argument. None at all. If you've got a long travel trailer behind you, co-phase will let you hear more of the folks behind you. Other than that a single antenna is the hot ticket.

Yep, it's illegal if it's inline with a CB, on or off, even if you have a ham ticket. If you've got a ham ticket it can be inline with a 10-meter rig, or a multi-band rig, but can't be used if you tune to 11 meters. If you don't have a ham ticket, an FCC inspector (but not any other law enforcement officer) can confiscate the amp if he finds it in your possession, inline or not, on or off. And probably will, if he has some reason to happen upon it -- most of them are ham operators with a hatred for CB.

In the real world, though, if you cause no complaints you're almost certain to be left alone no matter what you do with your CB. I've never known of anyone who wasn't specifically targeted to get popped for an amp. Most folks who've got them just hang them under the dash in plain view and have no problems. Most dedicated CB radio shops and every one I've ever been in sell amps (and export radios) and get away with it as long as they keep it hidden from the general public, don't sell anything over 400W, and don't have unlicensed techs working in the shop.

Of course, there's no guarantee that you won't end up in trouble if you install an amp because you are technically violating the law.

I'm with ya. I haven't even had a CB on the air for more than ten years now -- running a radio shop for what turned out to be too long soured my taste for the things. By now I'd have to replace all of the electrolytic capacitors in any of my radios just to power it up because they're sitting there just looking for an excuse to release their magic smoke. But I'll probably end up doing it some day when we get back out on the land like we're supposed to be where cell phone coverage is spotty at best. In town or near the interstate I'd just as soon never hear one at all.

Now that I've bumped up against the boundary of off-topic enough to leave it dented and hanging at a funny angle, I'll shut up.

 

its not off topic at all. I was looking for useful information and this thread is full of it. both legal and non lol

 

 

Love that console.