[Elecraft] KREF3 External Reference card

[Jan Holmer SM6TUW]

Hi
 
Someone pointed out that we all have different 49 MHz oscillators. I guess
that many K3 owners have oscillators without input for the voltage control.
This pin is indicated in the KREF3 shematic as pin 1  (VCTRL) of Z1. 
My KTCXO3-1 is manufactured by KS Electronics (part number 1099) and pin 1
(VCTRL) is not
connected internally. It can not be used in a PLL. I had to replace mine
with a VCXO.
I guess that is why Elecraft has cancelled that project, they would have to
swap oscillators.

*The design of the PLL is fairly simple and can be built on a small board
plugging directly into J4. 
*One has to consider the resulting phase noise and spurs of the locked
KREF3. 
*The Kref 3 must also fall back into a default mode when the extref is
disconnected (portable use) or if the PLL unlocks. 

I wonder if the promised optional board foor the K144XV allowing lock of the
116/118 MHz XO to the KREF3 is also cancelled ? 


Jan
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