Communications – Limitations and Advantages of CB Radio

CB Radio is a very different thing now than it was at the height of it’s popularity in the 70’s – cell phones have pretty much replaced the CB for everyone. But there are some very important or fun uses that a CB can still be valuable for. You do need to be aware of the limitations, as well as what CB Radio is capable of.

 

First the limitations:

RANGE:

      Lots of CB equipment is advertised as having a variety of ranges up to 20 miles. For AM-CB this is a bogus claim, since this is the range for a line-of-sight contact with absolutely zero interference and perfect antenna matching with full sized base-station antennas – a perfect world scenario. The actual range you can usually count on is 5 miles or less from Base to Mobile, or 2 miles from Mobile to Mobile, less if there is a lot of interference. Anything more than this with legal equipment is a fluke. There are some special features you can get that will help improve this situation, however.

INTERFERENCE: While CB popularity has died out pretty much in the US, it is in full swing in Mexico and many areas of Europe. This affects radio use here because we are near the peak of an 11 year sunspot cycle that allows the atmosphere to bounce CB signals for long distances – meaning signals from Mexico end up here when they’d normally only travel a few miles. The signals are low level and garbled, but they are also coming in from hundreds of radios at the same time, so the result is a whining hash of garbled interference on every channel (some channels worse than others) when you turn on the radio. Usually the interference is only during the daytime, but since this is when you’d get the most use out of your radio, it’s vexing at times. Some days you will hear virtually nothing – other days (fortunately not often) the interference will be so strong that you literally cannot hear someone a few blocks away from you.

Ok, now the things going for CB vs. other transceivers:

NO LICENSE REQUIRED!!

      Ham radio and the GMRS service, as well as other radio services that give equal or better range require an FCC license (the license free FRS radio band has a very limited range)

Cost: has dropped drastically for CB’s. It’s not unusual to spend as much on the antenna as the radio, for a basic setup! For this reason CB is often a cost-effective alternative to other radio equipment.

Size & Type: along with many technical advances, CB’s have miniaturized too, which helps in cramped vehicle cabs of down-sized vehicles. There are dozens of specialized varieties of CB’s that fit any use: hidden, waterproof, night illuminated; you name it, someone probably makes it. The old brick-sized walkie-talkies are a thing of the past, too, thanks to integrated circuits – some models are the size of a standard cell phone.

Features: like everything else electronic, CB has benefited from advances in technology from when it first was a craze. You can get just about any feature you want on a CB radio now for a fraction of what it used to cost – and some goodies that didn’t even exist for past CB’ers except as a fond wish.

      In addition to the standard Volume, Squelch, and Channel Selector controls that all CB’s should have, some important/popular extra features are:

 

  • Automatic Noise Limiter(ANL) or Noise Blanker(NB):
  • Extremely useful reception enhancement filters that cut static, engine noise, power line hum, etc.
  • Fine Tune/Delta Tune:
  • Not really needed to tune in to today’s radios which are much more frequency stable than older models. But can be very handy for tuning away from interfering signals while still being able to hear the person you are talking with. On models with SSB capability, fine tuning (usually called a “clarifier”) is a must, however.
  • Mic Gain:
  • Boosts the voice output of your microphone to make your transmissions slightly louder. A good thing, but too much of a good thing can be bad, so it has to be used but not overdone, or you end up louder, but garbled.
  • RF Gain:
  • a sensitivity control for the receiver. Works well for cutting interference from far away stations while allowing you to still hear close-by ones.
  • PA Switch:
  • Allows you to connect an outside speaker to the CB and use as a Public Address amplifier, or monitor the radio outside the vehicle.
  • Meters (S, S/RF, or S/RF/SWR):
  • gives a visual indication of input or output signals and characteristics. Radios with built in SWR meters usually have the adjustment controls for performing antenna tuning checks, also built into the radio. Some of the better featured radios have modulation meters, frequency counters, or other exotic monitors built in, as well.
  • Antenna/SWR Warning Indicator:
  • connected to a monitor circuit that checks for a tuning problem in your antenna that could damage the radio.
  • Instant Channel 19/9/Emergency/NOAA channel Monitors:
  • let you switch to an information channel quickly without hunting. Channel 19 used nationwide by Truckers for road condition information. Channel 9 is the former CB Emergency channel that is still monitored by a few police agencies in some areas of the country. NOAA channels are 24 hr weather broadcasts nationwide that also send out warnings for storms and tornadoes.
  • Roger Beep/Echo/other effects:
  • these are audio bells & whistles invented as Trucker toys for those who refuse to grow beyond the 10 year old level. Usually just annoying to most operators, the only remotely useful one is the Roger Beep, which does the NASA-type beep at the end of a transmission, useful in high noise areas.
    • Some popular accessory features you might hear of:
  • Preamp/Power Microphone:
  • Basically same feature as the Mic Gain on some radios, but built into the microphone itself.
  • Antenna Preamp:
  • boosts the received signal coming in from the antenna. Works well for weak signals, but keep in mind it will also boost any static or interference, too.
  • Booster/Footwarmer/Linear Amplifier:
  • boosts your transmitted signal – very illegal but popular. Usually surplus Ham radio amplifiers, which increase the output of your radio up to as much as 2000 watts, depending on the model.
  • VFO Tuning/Out-of-band/Funny Channels:
  • The frequencies above and below the CB band are relatively unused, and many CB’s can be modified to operate on them – illegally. Very popular for the long distance communication crowd, to get away from the noise on the regular CB channels.

 

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