It must be stressed at this point that in order to broadcast anything through a repeater at all you must hold a license to transmit. The rules and regulations on getting hold of a license and what you can use it for varies from one country to another. A good starting place is your countries Post Office. In the UK you can get more information from OFCOM and the national radio society RSGB.
Most repeaters have features that can be controlled by the person using it. These features range from being able to select an optimum antenna to being able to display screens of information and in some cases, even look at other repeaters that are within signal range
By far the most popular method used to control a repeater is a telephone dialling tone. These are really called DTMF which is an acronym for Dual Tone Multi-Frequency, named because the sound is made from two tones , one for each column of the keypad and one for each row. Pressing a keypad key produces a pair of tones representing the key that was pressed. The repeater electronics listens to these tones and identifies the key that was used to produced them. From there, different keys or combinations of keys are used to control actions elsewhere in the repeater.
For example, pressing the keys *160# will select one of the alternative picture and sound sources.
DTMF keypads are easy to build or can be purchased at low cost. It is even possible to hold a mobile phone close to a microphone and hear the tones from the phones earpiece.
If you want to know more about repeaters and how to use them you can contact us by clicking on the "more?" picture on the left or by reading about the specific design of GB3ZZ by clicking here.