Blonder Tongue Modulator Modification

[ChrisW6ATV]

Wiscojim-

I got curious and just tentatively re-figured out how to get Channel 1 from the OTM-3000. Looking at the code in the DIP switch settings, if you skip the left-most switch and concentrate on the next seven, you will see they are in reverse order (lowest bit on the left). So, the decimal numbers and resulting frequencies in whole MHz go like this:

DIP...... dec freq (add 0.25 MHz)
1001110 78 55 MHz
1010001 81 61
1010100 84 67
1011001 89 77
1011100 92 83
1100000 96 91

You will see a logic. Every digit higher equates to 2 MHz, with 78 equaling 55 MHz. So, subtract 5 and you should get 45 MHz:

DIP....... dec freq (add 0.25 MHz)
1001001 73 45?

This equates to switch settings in the format of the Olson manual like this:

SW1....... SW2
01001001 01000

I am pretty sure I tested this with my unit, but I did not have a restored TV set that could tune to channel 1 at the time, so I did it in some indirect way (such as looking at a spectrum analyzer, or tuning a VHF audio scanner and hearing the carriers or similar). Now that I have an RCA 8TS30 restored, I should hook up the unit and find out for sure, huh?