Beyond the Basics

The next two or three digits identify which fleet is active, and the last digit(s) identifies the subfleet.

Your task is to program your fleet map with the same size code assignments as the trunked system. If you do this accurately, you’ll track all the fleet-subfleet combinations used by the system. In other words, you’ll hear complete communications while monitoring a trunked system.

If you don’t already know the size codes used, you’ll have to guess at them. But since you don’t have to figure out all the blocks at once, this isn’t as hard as it seems. Select a size code for a block, and then press SRCH. Now listen to the communications. If you decide you are receiving most of the replies to the conversations with IDs assigned to the block you just programmed, then you’ve probably selected the right size code and can work on the next block of the map.

Finally, for most public safety systems there are some size codes which are more common. Size code 3 and size code 4 are probably the most common, followed by size codes 10, 11, and 12.

Fleet Map Size Codes

 

Size

Fleets

Subfleets

IDs

Blocks Used

 

 

 

 

 

 

 

 

 

0

 

Reserves block for Type II IDs

 

 

 

 

 

 

 

 

 

 

1

128

4

16

1

 

 

 

 

 

 

 

 

 

2

16

8

64

1

 

 

 

 

 

 

 

 

 

3

8

8

128

1

 

 

 

 

 

 

 

 

 

4

1

16

512

1

 

 

 

 

 

 

 

 

 

5

64

4

32

1

 

 

 

 

 

 

 

 

 

6

32

8

32

1

 

 

 

 

 

 

 

 

 

7

32

4

64

1

 

 

 

 

 

 

 

 

 

8

16

4

128

1

 

 

 

 

 

 

 

 

 

9

8

4

256

1

 

 

 

 

 

 

 

 

 

10

4

8

256

1

 

 

 

 

 

 

 

 

 

11

2

16

256

1

 

 

 

 

 

 

 

 

 

12

1

16

1024

2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

69

Page 69
Image 69
Radio Shack 20-426 manual Fleet Map Size Codes