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even interfere with each other to the point where it is impossible to clearly receive
any of the stations. A scanner, such as your BCT15, equipped with CTCSS and
DCS, c an code eac h r eceiv ed frequency with a specifi c sub-audible CT CSS or
D CS frequency or code. Then, when you receive multiple signals, you only hear
the transm ission with the CTCSS or DCS tone you progr ammed. If you do not
receive the correct tone with a signal, the scan ner’s squelch rema ins clo sed an d
you he ar no thi n g.
T he tables showing the available CTCSS frequencies and DCS codes are found in
the R eferenc e Secti on on Pag e 134 of this manu a l.
Conventional Scanning
C onventional scanning i s a relatively simple concept. Each group of users in a
co nvention al system is assign ed a sin gle freq uency ( f or simple x syst ems) or t wo
frequencies (f or repeat er syste ms). Any t ime on e of them tran smit s, th eir
transmission always goes out on the same frequency. Up until the late 1980s, this
was the prima ry way t hat radio syst ems opera ted .
Even today, there ar e many 2-way radio users who operate using a conventional
system:
• Aircraft
• A mat eur radio
• FRS/GMRS users
• Broadcast AM/FM/TV stations
• Many business radio us er s
When yo u wan t t o store a conventional system, all you need to kno w is the
frequencies t hey operat e o n. When you are scann ing a convent io na l system, t he
scanner stops very briefly on each channel to see if there is activi ty. If there isn’t,
the sca nner q ui ckl y moves to th e next chan nel . If the re i s, then t he s ca nner p auses
on the transm ission until it is over.
Simplex Operation
Si mplex system s u se a sing le f re qu ency fo r bo th tran smit a nd r ece ive . Mo st radios
using this type of operation are limi ted to line-of-sight oper ation. This type of radio
i s frequently used at constr uction job sites, and with inexpensive consumer radios
such as GM RS /FR S r adios. The r ang e is typ ica l ly 1- 15 m i les, dep en di ng u pon the
ter r ai n and many other factors .