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frequencies frequently frequenting frequency mixes, without the Panda

Discussion in 'CB Radio Modifications' started by kopcicle, Oct 4, 2017.

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Do you have any interest in a mono band HF portable?

  1. What happened to the Panda?

    1 vote(s)
    9.1%
  2. Pandas suck , death to all Pandas and your lame modifications

    0 vote(s)
    0.0%
  3. Not now son, I'm making toast !

    6 vote(s)
    54.5%
  4. Do you actually have a life away from meanigless posts about obsolete radios?

    1 vote(s)
    9.1%
  5. Cool, tell me more...

    4 vote(s)
    36.4%
Multiple votes are allowed.
  1. kopcicle

    kopcicle Sr. Member

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    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 :) .

    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


    This ought to keep you busy for a while .
     
    LeapFrog and tecnicoloco like this.

  2. Riverman71

    Riverman71 Part-time Member

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    I can see a potential problem with them "playing nice" at 3.6 and 7.22 Mhz. But 14 oughta be fine.
    Unless . . . your offsets aren't smack dab on the money. That's a ticklish area, remember. There, "In the general vicinity" is pretty much a roll of the dice. Oh, and that VCO output of 11.3250 is a little suspect, too. Believe it's a tad on the skinny side.

    That what you're lookin' for?
     
    #2 Riverman71, Oct 4, 2017
    Last edited: Oct 5, 2017
  3. 9C1Driver

    9C1Driver Sr. Member

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    Wow, I fell asleep after the 2nd paragraph. I did this. Uniden Madison 8719pll properly tuned and aligned with extra channels. I turn the power on and with a nice desk mic it sounds superb. Done.
     
  4. Riverman71

    Riverman71 Part-time Member

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    Well, yeah, that's one way to do it, I guess.
    Kinda takes the fun out of it though, doesn't it? :ROFLMAO:

    On second thought, 9C1, I think I prefer your method. LOL.
    Sure beats the heck out of checking Kopcicle's computations and conversions.
    Unlike you, I began at the end and worked my way up. o_O
     
    #4 Riverman71, Oct 5, 2017
    Last edited: Oct 6, 2017
  5. 9C1Driver

    9C1Driver Sr. Member

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    A local guy here several years ago had a Washington all done up with some wideband hifi mods. He had all the rack gear and heil mic and it sounded ok. He bought an HF rig and it worked a whole lot better for him. There is a lot to getting those set ups dialed in for sure.
     
  6. kopcicle

    kopcicle Sr. Member

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    Yeah, I was flat on my back with nothing but a computer and a few manuals/schematics. I'll admit it was a bit excessive. ;-)

    Yes it does. The numbers are correct. Replacing all the 27MHz with 3.5, 7.12, 14MHz is a bit of a trick. That comes next.

    This is all about a single band HF portable. Something that isn't available. If I can pull it off for around $100 I'll be happy .
     
    tecnicoloco likes this.
  7. Riverman71

    Riverman71 Part-time Member

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    Yep. Right as rain. Even that 11.3250 VCO Output.
    (Must have had something in my eye.) ;)

    Good luck with what clearly is one of the most interesting projects proposed and tackled on this site. Looking forward to hearing the results. If your soldering skill is in keeping with your logistical, the final product should be a thing of beauty. (y)
     
    #7 Riverman71, Oct 6, 2017
    Last edited: Oct 6, 2017
  8. TM86

    TM86 Destroyer of radios

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    If you haven't already seen them, here's some videos for inspiration:




    That second one is from a guy that has a few videos out there for converting CB's to various ham bands.

    Can't wait to hear how your efforts turn out.
     
    LeapFrog likes this.
  9. kopcicle

    kopcicle Sr. Member

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    I saw the 80m conversion and have some notes from now 404 pages. the original interstage transformers were retained and brute forced to 3.5MHz. Where gain suffered because of losses in the IF/RF chain small signal transistors (2N2222) were used to make up the difference.
    I don't think even the 33MHz trippler coil was changed to something near the 10.610 MHz crystal.
    Let's just say I applaud the effort but the implementation is sub-optimal.

    Briefly, the 10.61 oscillator needs to have the trippler coil changed to the fundamental and used as a low gain buffer amp, then mixed with the divider output, then mixed with TX oscillator to arrive at 3.5MHz. Both the IF(RX) chain and the RF (TX) chain need to be changed from 27MHz to 3.5MHz. If I remember right it's 4 each variable transformers, with one of those 4 in each being a double tuned transformer, plus the first RF transformer.

    Instead of tuned coils (Toko 10K) I'm going to wind torrids a bit on the L side and tune with parallel tune with a bit of C on the order of a few Pf .

    ...mumbles something about series tuned, singled ended stage gain limitations and a Panda
     
    LeapFrog and tecnicoloco like this.
  10. Riverman71

    Riverman71 Part-time Member

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    Must say you had us up until that business about winding your torrids a little lean. However, it was your closing thought (clue) that was a dead giveaway. Can't believe you threw it out there. Now clearly picturing that two-way mirror with you on the other side doubled over with laughter.

    Must confess I was thinking about investing my own $100 (should be able to do it cheaper than that since all work will be done in-house) and proceeding myself, but I think I'll just stick with my HF rig and save the indignation. Oh, wait---can't do that. I recently sold it for half what it's worth. :(

    It's clearly time I head back to the CB forums where I belong. What the? This is a CB forum! o_O
    It's not safe anywhere! :eek:
     
    undertaker likes this.
  11. kopcicle

    kopcicle Sr. Member

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    If I ever get to the point where I'm winding torrids I will provide extensive detail...
     
  12. Riverman71

    Riverman71 Part-time Member

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    Cool. I've never really had a good handle on the process.
    That pretty much goes for the physical aspect of serious radio building/modifying in general. Get me off the parchment (or display) and I'm a duck out of water.

    Good luck and thanks for being a good sport. (y)

    Jim
     
  13. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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    Not much too it. The trick is to wind the wire on a flat shuttle bobbin first if the wire is really fine and pass that thru the core. It makes winding a lot easier.

    [​IMG]
     
  14. Riverman71

    Riverman71 Part-time Member

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    Being a neat freak, I've never liked the sight of those (or the plastic ones that look like kite string winders) dangling off the back of the unit. And the miniature versions (0.325" L) are WAY beyond my capability :confused:, which is disappointing because they seem to work surprisingly well.
     
    #14 Riverman71, Oct 8, 2017
    Last edited: Oct 8, 2017
  15. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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    Why would they be dangling off the back of any unit? The bobbin just makes it easier to run the wire thru the toroid. After enough turns are made the wire is cut and the bobbin returned to the drawer, toolbox, work desk or whatever.
     

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