Answer: This scanner uses 16 switches set to either 1 or 0 to program the frequency. Here is the formula, with an example to work with:
Take the display and divide it into groups of 4 bits each:
01 02 03 04 |
05 06 07 08 |
09 10 11 12 |
13 14 15 16 |
1 |
2 |
3 |
4 |
Group 1 is as follows:
| Band
| MHz
| 1
| 2
| 3
| X
|
| VHF Lo |
30-50 |
0 |
0 |
0 |
0 |
| VHF Hi |
150-172 |
0 |
0 |
1 |
120 |
| UHF LO |
450-470 |
0 |
1 |
0 |
420 |
| UHF Mid |
470-490 |
0 |
1 |
1 |
440.0025 |
| UHF Hi |
490-512 |
1 |
0 |
0 |
460.0025 |
Bits 1, 2, and 3 are from the column 1, 2, and 3 above. To find bit 4, do the following:
The answer is between 3 and 5. If the answer is 4 or greater, then bit 4=0. If the answer is less than 4, bit 4=1.
Subtract either 3 or 4 from the number to leave a positive number 0 and less than 1. Multiply by 16. Enter the whole part of the number as HEX in group 2 above.
Subtract the whole number to leave a value again greater than 0 and less than 1. Multiply by 16 again. Enter the whole part of the number as HEX in group 3 above.
Subtract the whole number to leave a value again greater than 0 and less than 1. Multiply by 10 this time. Enter the whole part of the number as HEX in group 4 above.
Example: 40.125 MHz
- The 1 2 3 bits = 0 0 0
- 000x xxxx xxxx xxxx
-
- The formula yields 3.9707031, making bit 4 = 1
- 0001 xxxx xxxx xxxx
-
- Subtract 3 from 3.9707031, yielding 0.9707031
-
- Multiply 0.9707031 by 16, yielding 15.53125, and making group 2 = 15 (1111)
- 0001 1111 xxxx xxxx
-
- Subtract 15 from 15.53125, yielding 0.53125
-
- Multiply 0.53125 by 16, yielding 8.5, making group 3 = 8 (1000)
- 0001 1111 1000 xxxx
-
- Subtract 8 from 8.5, yielding 0.5
-
- Multiply 0.5 by 10, yielding 5, and making group 4 = 5 (0101)
The coding for 40.125 MHz is 0001 1111 1000 0101.
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