PLL02A Truth Chart (2 crystal AM)

[sunbulls]

I made this chart for the PLL02A 2 crystal AM Cybernets that I’ve been working with. The only 02A truth charts that I found on-line were for the SSB boards (not the same). I also prefer my chart with the pin numbers in reverse order. This is as they naturally appear on the print side with the front of the radio facing towards me. Pins 7 & 8 are normally at ground potential. Later I may make an expanded chart to include above and below frequencies.

 

[nomadradio]

That is very cool. Thank you!

I remember ages ago being puzzled about the "reverse" order of binary values for these radios. Channel 1's divisor is 74, the value for channel 40 is 30. Eventually, seeing that the VCO frequency is below the crystal it gets mixed with, it made sense. The difference between those two frequencies feeds into the PLL. When the VCO frequency goes up, the mixer output frequency goes down.

Does serve to explain why this kind of radio expands below channel 1 a lot better than it expands above channel 40.

73

 

[sunbulls]

The chart in my previous post was for the 2 crystal (10.240Mhz, 10.695Mhz) 02A AM Cybernet boards.

This is the 3 crystal 02A AM Cybernet version with the additional 11.8066Mhz crystal.