[K3] ideas for re-purposing our old K3 synthesizers

[inventor61 .]

I printed out the schematic of the original K3 synthesizer module.  The
diagram says 'rev. A4' and is dated 8 Jan 2010.  Hope that's close to the
as-built!  (probably is)

This gizmo appears to have an output range from 8.7 to 46 MHz.  I don't
know how much sauce it can develop but I have to imagine +10 dBm or so into
50 ohms, I bet it's flat across that range, and it looks like the thing
would be whistle-clean.

To get that, it needs a tight 49.38 MHz reference oscillator (I found a
0.5PPM TCXO for ~$30 from mainland China), and several common DC supply
voltages.

It also needs a small microcontroller or other way of providing the correct
serial peripheral interface command lines and interaction.  That processor
would also control the output frequency, perhaps with an encoder, or
whatever human interface might make sense.

But first, I am trying to see if developing a 'host' PCB would even be
fiscally wise to design and construct.  I mean, who needs a 8.7 to 46 MHz
VFO?

And, how mad would Eric or Wayne be with me about the ... um ...
semi-inverse engineering research ... I'd have to do to make this thing
operate?

On the other hand, I wager there's a thousand-plus of these modules sitting
around the planet looking for something to do.  The capitalist in me is
intrigued.

So, a bit of market investigation here:

a)  what would you do with such a device if you had one?  bench signal
generator?  beacon transmitter?  VFO for another radio?

b)  would you pay, say, $100 for a host board to operate your now-surplus
synthesizer?

c)  if someone *else *needed YOUR spare module for THEIR project, what
would you be willing to sell it to them for?  Free?  $25?  More?

73 es tnx
Steve KZ1X/4
<kz1x at  yahoo . com>
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[Johnny Siu]

Well, USD25 for the old synthesizers is good enough for me and I will be happy to sell it.
However, I cannot think of any interesting project for it.
73
Johnny VR2XMC
      寄件人︰ inventor61 . <[hidden email]>
 收件人︰ [hidden email]
 傳送日期︰ 2015年06月25日 (週四) 10:18 AM
 主題︰ [Elecraft] [K3] ideas for re-purposing our old K3 synthesizers
   
I printed out the schematic of the original K3 synthesizer module.  The
diagram says 'rev. A4' and is dated 8 Jan 2010.  Hope that's close to the
as-built!  (probably is)

This gizmo appears to have an output range from 8.7 to 46 MHz.  I don't
know how much sauce it can develop but I have to imagine +10 dBm or so into
50 ohms, I bet it's flat across that range, and it looks like the thing
would be whistle-clean.

To get that, it needs a tight 49.38 MHz reference oscillator (I found a
0.5PPM TCXO for ~$30 from mainland China), and several common DC supply
voltages.

It also needs a small microcontroller or other way of providing the correct
serial peripheral interface command lines and interaction.  That processor
would also control the output frequency, perhaps with an encoder, or
whatever human interface might make sense.

But first, I am trying to see if developing a 'host' PCB would even be
fiscally wise to design and construct.  I mean, who needs a 8.7 to 46 MHz
VFO?

And, how mad would Eric or Wayne be with me about the ... um ...
semi-inverse engineering research ... I'd have to do to make this thing
operate?

On the other hand, I wager there's a thousand-plus of these modules sitting
around the planet looking for something to do.  The capitalist in me is
intrigued.

So, a bit of market investigation here:

a)  what would you do with such a device if you had one?  bench signal
generator?  beacon transmitter?  VFO for another radio?

b)  would you pay, say, $100 for a host board to operate your now-surplus
synthesizer?

c)  if someone *else *needed YOUR spare module for THEIR project, what
would you be willing to sell it to them for?  Free?  $25?  More?

73 es tnx
Steve KZ1X/4
<kz1x at  yahoo . com>


 
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[wayne burdick]

Hi Steve,

Not to throw cold water on this, but.... the original KSYN3 requires a ton of firmware support, including a hand-tweaked table of thousands of PLL divider values pre-calculated and stored in flash memory. We shoehorn the DDS reference signal through a 3-kHz wide crystal filter in order to ensure no close-in spurs, then adjust the PLL divider values in real time so there are no gaps in the tuning range despite a nominal 20-kHz PLL step size. Lots of idiosyncratic math, and a critical calibration step ("VCO CAL").

So if each of your repurposed KSYN3s comes with a K3 front panel MCU and flash, no problem :)

73,
Wayne
N6KR


On Jun 24, 2015, at 7:18 PM, inventor61 . <[hidden email]> wrote:

> I printed out the schematic of the original K3 synthesizer module.  The
> diagram says 'rev. A4' and is dated 8 Jan 2010.  Hope that's close to the
> as-built!  (probably is)
>
> This gizmo appears to have an output range from 8.7 to 46 MHz.  I don't
> know how much sauce it can develop but I have to imagine +10 dBm or so into
> 50 ohms, I bet it's flat across that range, and it looks like the thing
> would be whistle-clean.
>
> To get that, it needs a tight 49.38 MHz reference oscillator (I found a
> 0.5PPM TCXO for ~$30 from mainland China), and several common DC supply
> voltages.
>
> It also needs a small microcontroller or other way of providing the correct
> serial peripheral interface command lines and interaction.  That processor
> would also control the output frequency, perhaps with an encoder, or
> whatever human interface might make sense….

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[Phil Wheeler-2]

Ah, but the original KSYN3 does have a nice chunk
of Aluminum attached :-)

73, Phil W7OX

On 6/24/15 10:06 PM, Wayne Burdick wrote:
> Hi Steve,
>
> Not to throw cold water on this, but.... the original KSYN3 requires a ton of firmware support, including a hand-tweaked table of thousands of PLL divider values pre-calculated and stored in flash memory. We shoehorn the DDS reference signal through a 3-kHz wide crystal filter in order to ensure no close-in spurs, then adjust the PLL divider values in real time so there are no gaps in the tuning range despite a nominal 20-kHz PLL step size. Lots of idiosyncratic math, and a critical calibration step ("VCO CAL").
>
> So if each of your repurposed KSYN3s comes with a K3 front panel MCU and flash, no problem :)
>
> 73,
> Wayne
> N6KR

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