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PLL02A Cybernet to 10 Meters

T

T23

Active Member
Apr 17, 2010
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I found this page ---> PLL02A

Basically it's about the PLL02A, I have a Cybernet Chassis, basically what I am getting from the charts on this page is that if I change the oscillator mixing crystal from 10.695 Mhz to 12.730Mhz it will put me right at 28.000Mhz on channel 1.

The paticular radio I have is an AM/SSB radio. Will it need realignment afterward?

Is this correct?

T23
 

It's been quite a while since I played with a PLL02A but I think you need to use a LOWER crystal frequency in order to RAISE the final frequency because the mixing scheme uses the difference in the two frequencies and adds it to local oscillator frequency. That means that in order to go higher the frequency difference must be greater. I'm thinking that 12.730 will put you on 24.930MHz for Ch. 1. You would need to use 9.660 MHz for Ch.1 to equal 28.000 MHz. Someone correct me if I am wrong please,it's been about 20 years since I played with a PLL02A and maybe things are different now. I am sure I had to LOWER the crystal frequency to move a CB up to 10m. In either event you will need to align both the transmitter and receiver sections for best operation.
 
Thanks for your reply Captain.... That was a great piece of info to know, This particular radio is a JCPenny 6241/SSB, its basically a re-branded mobile Colt Black Shadow 680 I think. I wanted to convert this rig for 10 meter use because of it's SSB capability.

Could someone point me in the right direction for re-alighning a radio properly?

T23
 
Many years ago, I acquired 3 older Hygain units that had been converted to 10 meter FM. These also used the PLL02a cybernet board.

One thing I remember about those units is that someone had taken the channel selectors out of them and wired each of the PLL's programming pins to their own switch. That allowed you to pull each individual pin high or low and control the programming that way.

It would take awhile to get something like that set up, but if you did you would end up with a lot more frequency coverage than you would using the standard 40 position selector.

Just a thought.
 
That is a good idea... I calculated the coverage ( which is decent ) of the conversion frequency coverage to be from 28.000 Mhz - 28.400 Mhz, this particular radio has AM USB and LSB, are these switches similar to these "thumbwheels" I hear about?


T23
 
T23 said:
That is a good idea... I calculated the coverage ( which is decent ) of the conversion frequency coverage to be from 28.000 Mhz - 28.400 Mhz, this particular radio has AM USB and LSB, are these switches similar to these "thumbwheels" I hear about?


T23
Click to expand...

No, they are simple SPDT switches. The center pin of the switch goes to the PLL chip, one side goes to ground and the other side goes to a voltage source, usually 5 volts. The switches are set up to program the PLL chip in binary fashion. You can get about 127 different "channels" that way or cover about 1.27 MHz typically.
 
Since 28.000 to 28.299 is the CW/Data portion of the 10 meter band, I would try to calculate the crystal needed to center your radio up around 28.400 or even 28.500... then using the program pins, you should have no trouble getting coverage from 28.300 up to 28.xxx which would be better from USB voice
 
How many of these switches would be needed?

And how would you use them, as in what one to put into position "A" and what one to put into position "B"?


T23
 
I was thinking about that, but that is not a mandatory band plan, but I'll run the numbers...


T23
 
Basically I would have to get a 9.260 Mhz crystal for channel 1 to start at 28.400 and a 9.160 Mhz crystal for channel 1 to start at 28.500 Mhz.


T23
 
Well I was thinking that most operators just scan about the band and search for activity, thats what I do...


T23
 

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