Thank you, Kop. Saved that one to my personal archives. I enjoy reading how it was done with crystals. Actually kind of fun finding the correct mix. Applied mathematics.
Well if numbers is what he wants then numbers is what he gets.
Remember this ...
First the numbers for 3.6 mhz
The uPD858 has a 7.8mhz IF and and Offset Oscillator frequency of 33.855 (result of a trippler from 7.8025) with a VCO frequency of 34.765mhz and a PLL "N" code of .91 for channel 1 (11m) .
With an IF of 7.8mhz and change the Offset Oscillator of 10.4mhz the resulting output frequency with an "N" code of 100 is 3.6mhz .This results in a VCO Frequency of 11.4mhz
The MB8719 with pin "10" low (142GTL COBRA et all) also has an IF of 7.8mhz and an Offset Oscillator frequency of 33.335mhz and a PLL "N" code of 1.43 for channel 1
With an IF of 7.8mhz and change the Offset Oscillator of 9.97 the resulting output frequency with the original "N" code of 143 is 3.6mhz . this also results in a VCO Frequency of 11.4mhz
The MB8719 with pin "10" high (148GTL COBRA et all) also has an IF of 7.8mhz and an Offset Oscillator frequency of 33.975mhz and a PLL "N" code of .79mhz for channel 1
With an IF of 7.8mhz and change the Offset Oscillator of 10.61 the resulting output frequency with the original "N" code of .79 is 3.6mhz . this also results in a VCO Frequency of 11.4mhz
Then the 02A (MC145106)
The PLL02A SSB . Has an IF Oscillator Frequency of 10.695 and a VCO Frequency of 17.555mhz . With an Offset Oscillator Frequency from the doubler of 20.105mhz (10.0525mhz) and counting down to go up from "2.55" "N" code results in channel 1 .
The PLL02A with an IF of 10.695mhz and an Offset Oscillator frequency of 8.4225mhz and a PLL "N" code of 255 for channel 1 results in 3.6mhz. The VCO output is now 5.8725.
Just the crystals for these conversions would hurt a wallet ..There is an alternative . The LTC1799 VCO . With nothing but a resistor to adjust for frequency and all these modifications having a doubler or trippler already in place to be re-purposed for for a buffer/amplifier what could go wrong ? The Ltc1799 can be had for as little as $10 on a board with a bypass cap and multi turn potentiometer . Check ICM (note ICM has effectively closed its doors after 60 years) crystal prices lately ?
Of course the trippler transformer and the VCO transformer would have to be re-tuned as well as the plethora of 3.5mhz transformers to make the RX and TX chains work . After that getting the RF through a 3 watt driver and 12 watt final would be trivial .
Then the numbers for 14.150Mhz
The MB8719 with pin "10" high (148GTL COBRA et all) also has an IF of 7.8mhz and an Offset Oscillator frequency of 33.975mhz and a PLL "N" code of .79mhz for channel 1
With an IF of 7.8mhz and change the Offset Oscillator of 21.16Mhz the resulting output frequency with the original "N" code of .79 is 14.150mhz . this results in a VCO Frequency of 21.950mhz
The MB8719 with pin "10" low (142GTL COBRA et all) also has an IF of 7.8mhz and an Offset Oscillator frequency of 33.335mhz and a PLL "N" code of 1.43 for channel 1
With an IF of 7.8mhz and change the Offset Oscillator of 20.52Mhz the resulting output frequency with the original "N" code of 143 is 14.150mhz . this results in a VCO Frequency of 21.950mhz
The uPD858 has a 7.8mhz IF and and Offset Oscillator frequency of 33.855 (result of a trippler from 7.8025) with a VCO frequency of 34.765mhz and a PLL "N" code of .91 for channel 1 (11m) .
With an IF of 7.8mhz and change the Offset Oscillator to 21.04Mhz the resulting output frequency with an "N" code of .91 is 14.15mhz .This also results in a VCO Frequency of 21.950mhz. (I still find this curious)
As an alternative an IF of 7.8mhz and change the Offset Oscillator to 20.95Mhz the resulting output frequency with an "N" code of 100 is 14.15mhz .This also results in a VCO Frequency of 21.950mhz. This gives some interesting advantages for the BCD to 7 Segment two digit read out.
And 7.12Mhz
The MB8719 with pin "10" high (148GTL COBRA et all) also has an IF of 7.8mhz and an Offset Oscillator frequency of 33.975mhz and a PLL "N" code of .79mhz for channel 1
With an IF of 7.8mhz and change the Offset Oscillator of 14.13Mhz the resulting output frequency with the original "N" code of .79 is 7.12mhz . this results in a VCO Frequency of 14.92mhz
The MB8719 with pin "10" low (142GTL COBRA et all) also has an IF of 7.8mhz and an Offset Oscillator frequency of 33.335mhz and a PLL "N" code of 1.43 for channel 1
With an IF of 7.8mhz and change the Offset Oscillator of 13.49Mhz the resulting output frequency with the original "N" code of 143 is 7.12mhz . this results in a VCO Frequency of 14.92mhz
The uPD858 has a 7.8mhz IF and and Offset Oscillator frequency of 33.855 (result of a trippler from 7.8025) with a VCO frequency of 34.765mhz and a PLL "N" code of .91 for channel 1 (11m) .
With an IF of 7.8mhz and change the Offset Oscillator to 21.04Mhz the resulting output frequency with an "N" code of .91 is 14.15mhz .This also results in a VCO Frequency of 21.950mhz. (I still find this curious)
As an alternative an IF of 7.8mhz and change the Offset Oscillator to 20.95Mhz the resulting output frequency with an "N" code of 100 is 14.15mhz .This also results in a VCO Frequency of 21.950mhz. This gives some interesting advantages for the BCD to 7 Segment two digit read out.
back to the 02A (MC145106)
The PLL02A SSB . Has an IF Oscillator Frequency of 10.695 and a VCO Frequency of 17.555mhz . With an Offset Oscillator Frequency from the doubler of 20.105mhz (10.0525mhz) and counting down to go up from "2.55" "N" code results in channel 1 .
The PLL02A with an IF of 10.695mhz and an Offset Oscillator frequency of 10.1625mhz and a PLL "N" code of 255 for channel 1 results in 7.12mhz. The VCO output is now 7.6325Mhz.
The PLL02A SSB . Has an IF Oscillator Frequency of 10.695 and a VCO Frequency of 17.555mhz . With an Offset Oscillator Frequency from the doubler of 20.105mhz (10.0525mhz) and counting down to go up from "2.55" "N" code results in channel 1 .
The PLL02A with an IF of 10.695mhz and an Offset Oscillator frequency of 13.6825mhz and a PLL "N" code of 255 for channel 1 results in 14.120mhz. The VCO output is now 11.3250Mhz.
All this ignores the onset and offsets contained in the MB8719 and of the three crystals in the uPD858 as well as the curious PLL02A. What you have here is the math for getting it there. As in somewhere in the general vicinity. Getting it on the proper side of and a comfortable distance away from the filter skirt for proper AM and SSB modes is an exorcise (exercise) for the reader
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The several things I have not done are place the frequencies into such as
http://leleivre.com/rf_mixerspur.html
or...
Explore the possibility of winding toroids with a little +L and tuning down with a trimmer cap of a a few Pf . Cheaper and easier than sourcing all the Toko 10-K transformers
.
The only real issue after getting everything past the mixer screwed into 3.6, 7.12, 14Mhz respectively, and the whole 7.8025/7.7975 offset thing (for the MB8719) is getting the 2SC2166 et all driver and the 2SC1969 final to play nice at 3.6, 7.12, 14Mhz respectively. I see a bunch of experiments there as Helge's AN779 only deals with pairs and broadband use. At least the information is there (MRF475 and 476 are similar enough) for a fairly straight forward adaptation to single ended use. The original functional test circuits may also be of use. If you're getting the idea that I have yet to try to get something other than 27Mhz through the driver an final, you are correct . I'm still looking for TOKO 10-K transformers @ 3.5, 7, 14Mhz
No I didn't just put this together . I had it laying around.
The level diagrams in the realistic service manual are golden
The PhotoFact is again golden
>>>>Do keep in mind that the gain increase for the 2166 and the 1969 will be a factor of 9 give or take. Don't be surprised if things are a bit "unsettled" at 3.5MHz<<<
This ought to keep you busy for a while...
Will copy. Have friend who is much better than I with crystal freqs. He used to change them out on the fly back in the day. Company called Kingfisher he used to work for had capabilities using this. His radio and his license allowed it all. Damned my head is hurting after reading that.
