New expansion - UPD858 SSB chassis

[Edd200sx]

I’d have to check the xtals

Those are very rare down here, can only recall records of doing one in 10+ years, and that was for a routine repair, not a modification.

At a minimum, we would need a schematic, the crystal frequencies, and the downmix frequencies (N-codes) for channel 1 and 40 on each band.

On the plus side, no need for broadbanding mods, looks like it was designed in the first place for that bandwidth...

I had a good search online can’t find a schematic for it.
Have to keep digging

[lbcomms]

I had a good search online can’t find a schematic for it.

In most cases it doesn't have to be exact, if the PLL area is identical that will be good enough.

Failing that, that section will need to be reverse engineered, which will add lots of time to the project (well the first one you do)...

[Edd200sx]

IMG_9331.jpeg

Best I can do is this pic for now.

145106 pll with 4008’s

[Techquest]

Look for the Dirland SS3900 its a 12 band two groups of 6

[Otter]

Crystals are 12.66 and 15.36. The frequency at the bottom of the lowest band (12.66MHz) is 24.265, Low band with Hi Xtal (15.36) is 26.965

The varicap tuning for the front end and the output comes from a resistor ladder arrangement which provides a voltage based on the most significant three output lines from the binary adders.

[Edd200sx]

Crystals are 12.66 and 15.36. The frequency at the bottom of the lowest band (12.66MHz) is 24.265, Low band with Hi Xtal (15.36) is 26.965

The varicap tuning for the front end and the output comes from a resistor ladder arrangement which provides a voltage based on the most significant three output lines from the binary adders.

Cheers Tim

[lbcomms]

Best I can do is this pic for now.
145106 pll with 4008’s

That's almost enough information, just need the PLL "N" codes for channels 1 and 40 on each band (Excel will use this to work out channels 2 to 39).

Easiest way is to measure the frequency at pin 2 of the MC145106 PLL and multiply the MHz result by 100.

Example, the Uniden 858 chassis has 0.91 MHz on channel 1 and 1.35 MHz on channel 40 at the equivalent pin on the 858 chip.
0.91 x 100 = 91 and 1.35 x 100 = 135, so the "N" codes on that chassis go from 91 on channel 1 to 135 on channel 40.

This will need to be done for each bank of 40 channels in the radio.

There should be 3 spare pins on the Nano which could be used to control the varicap tuning if you want to do away with the existing band switching scheme.

[Otter]

For the 158, surely the n-codes drop out of this ? (Bottom band Ch.1)
N = 100x( 24.265 -12.66 - 10.695) = 91
You'd add 45 to the ch.1 N-code for the next 5 bands.
91,136,181,226,271,316
Then the Hi band Xtal:
Using the hi Xtal N = 100x( 26.965 -15.36 - 10.695) = 91
91,136,181,226,271,316

Channel 40 N-codes are channel 1 N-code + 44

[Murf]

Hi, I have an old AWA Teleradio AC-5112S Marine 27MHz transceiver with a D8284 PLL.
Has this mod been successfully applied to a radio with this PLL yet please?
Great work by the way, kudos.
Thanks,
Murf. VK4BEM/VK3MP

[lbcomms]

Most of the work on that radio will be to add LSB - marine radios are USB/AM only and nearly all 26/27MHz usage other than marine is LSB. So to make it usable, you'll need to add LSB mode first. It's a standard 2824 chassis with the LSB parts left out, so you'll probably need a junker radio to get the coils etc that you'll require.

Once that is done, it's almost the same as the 858 chassis to modify / expand, click the link below:

viewtopic.php?t=59085

Enjoy...