The MOD

[TM86]

I believe there might be a voltage difference between the channel selector (8v?) and the input lines you use on the Arduino (3.3v or 5v). You would need some type of voltage translator on each line to buffer the difference.

Could probably use a couple of resistors per line as a voltage divider and tap the arduino in at the middle. I might try that when I have the time. Which may be a while.

I really thought someone would have done all of this as a kit by now. It's not like it's magic.

 

[NZ8N]

I had thought of it, and the buffer thing, but never got around to designing a board to do so.

 

[nomadradio]

You would only need to unhook the 8 Volts from the selector and instead feed the correct logic-high voltage, 5V or 3V into the selector.

Much simpler.

73

 

[mechanic]

I wonder if one of those Arduino gizmos could be programmed and configured to do something like this? I have been interested in the Arduino but I haven't found a need to use it. Something like this would get me going maybe.

I've started with Arduino and with the IDE and a good plan it should work. The Atmel processor should be able to most anything..... If done right an old Commodore 64 should do a few things.

73 mechanic

 

[loosecannon]

Ah the MOD, my old stomping grounds.

There were about six of us that were ultra excited when weakstation showed up on the group and told us he would draw up hand wiring sheets so that we could all wire up our own mod boards.
Then we would buy EPROMS and mail them to him to be programmed.

the instructions were about 30 pages long, and involved A LOT of wrapping kynar wire around IC chip legs.
the display was done on 7400 series chips. five of them IIRC.

one of the coolest parts of it was "the button" which was a 20 channel jump feature. the cool part was that it was a tactile switch mounted behind the RX/TX LED with a piece of solid wire sticking out the back of the rubber boot for the LED and the other end of the wire glued to the switch.
It turned your LED into a little momentary switch for jumping channels!

we had many more people start joining up after the group got active, but in the beginning there were only a few of us with the temperament for doing the hand wiring.
There was no way to test along the way, and what if you got done and it didn't work!?

Later on PIC chips were the order of the day, and im not sure if it ever evolved to using ATMEL chips or not. I had moved on by then.

I still have a box full of different versions of the mod boards, as i became the main beta tester for Farmer Dave at one point.
I will take some pics of them just for posterity, but i honestly don't know what to do with them at this point.
I always imagined that someone else out there might want them, but i've never found anyone.
If any one on the forum wants them, you can PM me here.
Im only going to get rid of it all or nothing LOL.
LC

 

[kopcicle]

The hard-wired EPROM technology at the heart of this setup is pretty well obsolete. Takes a lot of wiring, to boot. Really too many wires to build by hand without circuit boards

Modern-day equivalent products you can buy are mechanically a lot simpler, based on single-chip microcontrollers. Fewer chips, fewer wires. A guy in Austria named (I think) Gerhard Maurer makes a whole line of PLL upgrades. And another one in Australia has a setup that puts three digits behind the radio's channel windo.

Only way you can copy those to build your own is to obtain the internal programming for the microcontroller chip, or write your own. That's the one difference between the old way and the new way. The code contents of the 'weak station' EPROM chips was made available. The program code that runs the newer stuff is usually not circulated.

Progress giveth, progress taketh away.

73

http://funkservice.at/en_pll-modul.htm
https://www.worldwidedx.com/threads/pics-of-upd2824-pll-radio-modified-by-stn.194714/
https://www.worldwidedx.com/threads/digimax-lite.80913/
https://www.worldwidedx.com/threads...y-mixes-without-the-panda.220999/#post-603990

 

[TM86]

I've started with Arduino and with the IDE and a good plan it should work. The Atmel processor should be able to most anything..... If done right an old Commodore 64 should do a few things.

73 mechanic

IIRC there was a magazine article (Popular Communications?) where a guy had wired a C64 to control his CB. He'd even built a scan function that sensed busy channels when the squelch signal changed. This would have been very early 90's.

So, yeah, a C64 could be used. Now, if you want low power and small size, a C64 emulator running on a RasPi might be the ticket.

 

[mechanic]

IIRC there was a magazine article (Popular Communications?) where a guy had wired a C64 to control his CB. He'd even built a scan function that sensed busy channels when the squelch signal changed. This would have been very early 90's.

So, yeah, a C64 could be used. Now, if you want low power and small size, a C64 emulator running on a RasPi might be the ticket.

Basically the channel knob, in a 23 channel crystal CB, controls the frequency by connecting the correct crystals to mix to make the wanted channel. Same thing for a PLL synthesized 40 channel CB. Sort of connecting the right "dots" to have the wanted channel. This can be done by a microprocessor, programmed to open or close the same "dots" or in this case switches.
Expanding this to cover 25 to 30 mHz is simple when controlling a VCO (or PLL) and using a DDS circuit, even more frequency coverage can be had. Using a Cobra 148 GTL should be easy enough but the limitation of frequency coverage is limited by the design of the chassis, that is the CB chassis is rather narrow, usually 26.5 to 28.3.
With the Commodore 64 and through the user port with a switch interface, one can control diodes or transistors to switch channels in 10 kHz segments. Yes a Raspberry Pi can do this and has far more power than the Commodore 64. Arduino could also be used with a rotary encoder.

73 mechanic

 

[loosecannon]

here is a very early version of using a microprocessor to control your channels in a CB radio.
This one was advertised in the old Secret CB books, and this is the first one i've actually seen installed in a radio.
https://www.ebay.com/itm/Cobra-2000...051841?hash=item23c2fa7f41:g:nY0AAOSwm~hdS2Xh

LC

 

[mechanic]

here is a very early version of using a microprocessor to control your channels in a CB radio.
This one was advertised in the old Secret CB books, and this is the first one i've actually seen installed in a radio.
https://www.ebay.com/itm/Cobra-2000...051841?hash=item23c2fa7f41:g:nY0AAOSwm~hdS2Xh
View attachment 30574
LC

Found some info on the Micromonitor.....

http://www.cbtricks.com/pub/secret_cb/vol_15/graphics/secret_cb_vol_15_pg05_06.pdf

Interesting stuff! I'm digging deeper!

73 mechanic