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| This Section is under construction |
Citizens' Band radio (remember that? Often shortened to CB radio) is, in many countries, a system of short-distance radio communications between individuals on a selection of channels within the 27-MHz (11 meter) band. In many countries, CB does not require a license and, unlike Amateur Radio Radio, it may be used for business as well as personal communications. Like many other two-way radio services, Citizens' Band channels are shared by many users. Only one station may transmit at a time.
Other stations must listen and wait for the shared channel to be available. Over time, several countries have created similar radio services, with varying requirements for licensing and differing technical standards.
Freebanding
Operation on frequencies above or below the citizen's band is called "freebanding". While frequencies just below the CB band, or between the CB band and the amateur radio 10-meter band seem quiet and under-utilized, they are sometimes allocated to other radio services and unauthorized operation on them is illegal.
Freebanding is done mostly with amateur radio equipment modified to transmit on 11 meters, foreign CB radios that may offer different channels, or with radios intended for export (marketed as amateur radio 10 meter export radios). This type of radio activity although wide spread throughout the world is in fact illegal in quite a few countries, the UK being one such country where only 80 FM channels are legal.
Many freeband operators use amateur radios modified to transmit out of band which again in some countries use of amateur radios modified to operate outside their required bands is illegal. Today many types of amateur radios can be found on CB and freeband, ranging from full-coverage HF transceivers to simpler 10-meter mobile export radios.
Why is Freebanding so popular?
Why is Freebanding so popular?
Putting aside the fact that it's illegal and free from the constraints of a licence, in one word - Propagation, all frequencies in the HF spectrum (3 to 30 MHz) can be refracted by charged ions in the ionosphere (upper atmosphere). Refracting signals off the ionosphere is called skywave or in CB lingo 'skip', as the signal 'skips' off the upper ionosphere. Freeband operators have communicated across thousands of miles, sometimes around the world, making initial contact on the internationally
recognized calling frequency (27.555 MHz), then moving to another frequency. Even low-powered 27 MHz transmitters can sometimes transmit over long distances when propogation conditions allow.
The ability of the ionosphere to bounce signals back to earth is caused by radiation from the sun. The amount of ionization possible is related to the 11-year sunspot cycle. In times of high sunspot activity, the band can remain open to much of the world for long periods of time.recognized calling frequency (27.555 MHz), then moving to another frequency. Even low-powered 27 MHz transmitters can sometimes transmit over long distances when propogation conditions allow.
During low sunspot activity, it might not be possible to 'skip talk' at all except during periods of sparadic electron propagation, which occur from late spring through mid-summer.
Operation on 11 meters 'Freeband'
While illegal in most countries, the level of organisation on 11 meters is surprisingly good, in some ways putting amateur radio to shame. A lot of this organisation can be attributed to the Italian Freeband group 'Alpha Tango'.
- Country Codes / Divisions
For international DXing (long distance communication) each country of the world is given a unique number called a 'division'.
For example England is division 26
A chart showing division codes can be found here.
- Callsigns
All Freebanders should have their own individual call sign. A call sign can be issued by one of the many Freebanding groups for example
Tango Mike, Foxtrot Bravo, Delta Xray.
The call sign comprises of : -
Divisioncode (country code), e.g. 26 for England
Initials of the group, e.g. DTUser's unique number, e.g. 1496
This would be 26DT1496.
- Transmission Modes
I am sure you have heard of AM or FM, the mode of transmission favoured for Freebanding is Single SideBand (SSB). The SSB mode can either make
use of the Upper Side Band (USB) part of the radio wave, or the Lower Side Band (LSB) part. Freebanders generally use Upper Side Band (USB). Because the SSB mode of transmission is so much more effective and efficient than the usual FM or AM modes, much greater distances can be
covered.
