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February 28, 2007 7:56 PM   Subscribe

CBRadioFilter: I want to add one to my car. Help please!

Recently, a few of my friends have decided to get CB radios for their cars, and I'm thinking about joining in on the craze. Problem is, I don't have much money to spend, and I really don't know what to get.

I want something small and compact if possible; I don't want this taking up a lot of room in my car. I'm cool with the antenna, but if I can avoid having some massive 6-foot monstrosity on my car, I'd love that. I do like the idea of the PA system function that most CB's seem to have, so if I can get one with a PA speaker, that'd be great.

Cost is the major factor here; I've seen a few in the $30-40 price range, and I like that figure. Ebay is perfectly fine, but in that case I would prefer it be a seller that often sells these items (i.e. a one-time offer may not help me, since I probably won't be getting this for at least another week or two).

So, in short, I'd like a compact CB radio with a PA function (and if possible, an included speaker), and I would like it to be as cheap as possible. Any help would be greatly appreciated!
posted by DMan to Technology (7 answers total) 1 user marked this as a favorite
Where do you live? Here in Alaska, and I'm betting in just about any rural-like area, (older) CB radios are a dime a dozen. I've seen them at garage sales for $2; maybe you could check your local Freecycle to see if anyone is wanting to get rid of one?
posted by rhapsodie at 8:52 PM on February 28, 2007

We have this handheld CB and use it with an external antenna and it works pretty damn good.
posted by disaster77 at 9:49 PM on February 28, 2007

If you buy used, freecycle, etc (or if you buy new, except I imagine the salesperson would mention this): remember that you must tune the antenna to your car. It's possible to damage the radio itself by transmitting with an untuned antenna. Any CB shop will have the equipment (a standing wave meter) to tune your antenna. It will probably cost $30-40 for the tuning alone.

Of course this is a non-issue if you buy a handheld CB.
posted by mendel at 4:35 AM on March 1, 2007

Four things.

Antenna - in theory you'll get best performance from a whip (straight) antenna, but this is also the ugliest solution. I'd look for an antenna that has part of its length coiled into a "spring". They're the same length as a whip antenna but the length is coiled up so they're less obtrusive.

Centre-loaded (the spring is halfway up the antenna) is in theory better than base-loaded (spring at the bottom) but in practice I don't think you'll see much difference. These days you can buy pre-tuned antennas that require almost no SWR adjustment, so I'd look for a pre-tuned, base-loaded antenna.

Ground plane - I think this is what mendel refers to above when he says "tune the antenna to your car". The antenna works better if it's sitting in the centre of a big sheet of metal. Moving the antenna around the car changes it's properties slightly. The "best" (and also the least attractive) mount point is the centre of the roof, then the roof gutter, then the wing, then the wing mirror. Aluminium makes for a bad ground plane - if your car body is aluminium, or you mount the antenna on a wing mirror, you'll probably need a ground plane kit. I'd mount halfway down the roof gutter as a reasonable compromise between practicality and performance.

Mounts - your choices are magnetic (sticks to roof, guaranteed to scratch), permanent (drill hole in body work) or the various types of screw-on mounts for gutter, boot, wing mirror, etc. Again, I'd go for a screw-on gutter mount.

SWR - adjusting the antenna length with a SWR meter is an easy process (connect the SWR meter between the radio and antenna. Select a channel in the middle of your range. Transmit briefly, check reading. Adjust grub screw on antenna. Repeat until you get lowest possible reading). I wouldn't pay someone to do it; one of your friends almost certainly has a meter and they're dirt cheap anyway.
posted by Leon at 6:26 AM on March 1, 2007

Heh. Last time I did this, most cars still had roof gutters :) Maybe you should do your own research on mounts...
posted by Leon at 6:36 AM on March 1, 2007

For just getting started I'd buy the cheapest radio Radioshack has and their mag mount base loaded antenna. The antenna will be matched close enough right out of the box. Though if your friends are at all serious someone will have an SWR meter, they ain't all that expensive and the actual tuning is pretty easy. The mag mount antenna will scratch a bit but that can be minimized with a few coats of wax. It's big advantage is you don't need to drill any holes and if you hit it with a tree it just pops right off rather than breaking or damaging your car.

Once you decide whether you like the hobby or not you can invest in a more whizzy radio and a permanent mount antenna tunned to the specific channel your circle uses.
posted by Mitheral at 7:40 AM on March 1, 2007

My CB days were probably about a decade ago, but I got my stuff back then from RadioShack. While it might not be as fancy (they do sell some higher-end CB stuff now), it works fine. That said, $45 seems to be the cheapest, so I'll second rhapsodie—there's tons of old radios out there that are just as good (or better, given the "they don't make 'em like they used to" scenario). If you do go for new, a lot of CBs include NOAA weather radio now. (This isn't anywhere near the CB band in terms of frequency, but since it's receive-only, it's not a huge deal.)

The 'problem' with antennas is that CB is pretty low-frequency (27 MHz), technically HF, so the antennas are pretty darn long. (And running an improper antenna will not only result in poor performance, but it can do damage to the radio.)

I never did the PA thing, but not all CBs have that feature, so shop carefully. You'll need an external speaker, obviously; usually it's mounted in the engine compartment, just inside the grille.

I'm not sure how familiar with CB you are; it's got 40 channels, but you'll sometimes see "120 channel" radios that make use of SSB (Single Sideband: there's lower sideband, upper sideband, and 'dual' sideband, which is the AM that they generally use).

A couple cautions:
- The US CB band isn't the same as CB in some other countries, especially European ones. If you're shopping eBay, keep that in mind.

- There's a 'shady underbelly' of CB involving people modifying their radios for "freeband" (going outside of the CB band limits), and using way, way more than the 4 Watts (12 Watts PEP in some cases) that's allowed. They're not sold commercially, of course, but if you're buying CBs from a guy in a dark alley or something, just be aware that there is such a thing as 'illegal' CBs.
posted by fogster at 8:42 AM on March 1, 2007

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