The SP10 is a 1 watt handheld radio transceiver designed to operate on one
of 16 different frequencies assigned to low power/itinerant communications
in the VHF-hi business band (150.775-174 Mhz.). While this is one of
Motorola's "low end" radios, the quality is still up to Motorola's
excellent standards. The SP10 is commonly available; even being sold by
Radio Shack, and a preliminary inspection indicates that the unit should
offer many opportunities to the RF hacker. A full review of the SP10
appears in the February 1996 issue of Popular Communications magazine.

To program the radio, remove the battery compartment cover, battery, and
plastic cover underneath the battery. On the bottom right hand side of the
radio you will see four dip switches. The position of the dip switches is
what determines the operating frequency. Use the table below to determine
what dip switch settings pertain to what frequency; where 0=ON and 1=OFF.

Frequency   Switches                   Frequency   Switches
---------   --------                   ---------   --------
151.625     0011                       151.655     1000
151.685     0101                       151.715     1010
151.775     1001                       151.805     0110
151.835     0010                       151.895     1101
151.925     0001                       151.955     1100
154.490     1011                       154.515     0111
154.540     1110                       154.570     1111
154.600     0000                       158.400     0100

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It would be my guess that most, if not all, low-end Mot handhelds have a
similar method of programming. Also, the Relm MPV32D
http://www.usascan.com/files/mp32.html is another possibility, since they
are easily field programmable.