The local Oscillator and the 12F683 PIC (U3) - as configured in the V8.3 kit - provides for 16 switch-selectable "center" frequencies, depending upon the 16 possible settings for the dip switch, SW1 (Included in the resistor/capacitor bag in an anti-static bag holding the programmed PIC, the PIC socket, the DIP switch and the 5 volts LM7805 TO-220 cased regulator IC.

The programmed PIC, (Tom KM5H's v2.4 code), contains the following set of center frequencies for DIP switch inputs 0000 to 1111.  These center frequencies were arrived at using the assumption that the sound card to be used for the RX would have a 96k Hz bandwidth.

The "Rocky Ini" column contains the settings for the Rocky.INI file to populate the Band dropdown list and dial the center frequencies into Rocky (see below).


SW1 Setting Decimal Value Center Frequency Rocky Ini Setting 4x Center Frequency Low End* Hi End*
0000 0 1.846 1.846MHz_0000=1846000 7.384 1.798 1.894
0001 1 1.892 1.892MHz_0001=1892000 7.568 1.844 1.94
0010 2 3.546 3.546MHz_0010=3546000 14.184 3.498 3.594
0011 3 3.846 3.846MHz_0011=3846000 15.384 3.798 3.894
0100 4 7.046 7.046MHz_0100=7046000 28.184 6.998 7.094
0101 5 7.221 7.221MHz_0101=7221000 28.884 7.173 7.269
0110 6 10.146 10.146MHz_0110=10146000 40.584 10.098 10.194
0111 7 14.046 14.046MHz_0111=14046000 56.184 13.998 14.094
1000 8 14.271 14.271MHz_1000=14271000 57.084 14.223 14.319
1001 9 18.114 18.114MHz_1001=18114000 72.456 18.066 18.162
1010 10 21.046 21.046MHz_1010=21046000 84.184 20.998 21.094
1011 11 21.321 21.321MHz_1011=21321000 85.284 21.273 21.369
1100 12 24.936 24.936MHz_1100=24936000 99.744 24.888 24.984
1101 13 28.046 28.046MHz_1101=28046000 112.184 27.998 28.094
1110 14 28.092 28092MHz_1110=28092000 112.368 28.044 28.140
1111 15 28.346 28.346MHz_1111=28346000 113.384 28.298 28.394
      (* predicated on 96 kHz soundcard, providing 48 kHz either side of the center frequency)

For example, the center frequency of 7.046 mHz corresponds to the binary string 0100 and would set SW1 as follows:
SW1 Set to 0100 for 7.046 mHz
Using a 96 kHz soundcard, this yields a bandwidth of 7.046 +/- 48 kHz (6.998 - 7.094 mHz).

Setting Up Rocky's ".INI " file

You can program Rocky so that the above settings are made available in the dropdown list that Rocky uses to "dial in" the center frequency. You do this by making entries in the "ROCKY.INI file. If you installed Rocky, using the defaults, this file is available at:
C:\Program Files\Afreet\Rocky\Rocky.INI

You need to edit the file using Notepad or a similar text editor, and replace the "[Band]" section with the following

  1. [Bands]
  2. 1.846MHz_0000=1846000
  3. 1.892MHz_0001=1892000
  4. 3.546MHz_0010=3546000
  5. 3.846MHz_0011=3846000
  6. 7.046MHz_0100=7046000
  7. 7.221MHz_0101=7221000
  8. 10.146MHz_0110=10146000
  9. 14.046MHz_0111=14046000
  10. 14.271MHz_1000=14271000
  11. 18.114MHz_1001=18114000
  12. 21.046MHz_1010=21046000
  13. 21.321MHz_1011=21321000
  14. 24.936MHz_1100=24936000
  15. 28.046MHz_1101=28046000
  16. 28092MHz_1110=28092000
  17. 28.346MHz_1111=28346000

and SAVE the ini file.

Setting Multiband mode in Rocky

You can then go into Rocky, go to the top menu and click on VIEW > SETTINGS, and then click on the DSP tab. In the DSP tab, make sure that the Local Oscillator option of "Multi-Band" is clicked (this enables the dropdown list in the upper right hand corner of the Rocky screen

Dropdown Menu