[Elecraft] [Elecraft_K3] New Elecraft Product: PLL Reference Lock Option for the K144XV 2-Meter Module

[Edward R. Cole]

Wayne, etal:

I'm asking for someone else that has the K144XV (I don't).

With the addition of the K3EXREF and K144RFLK, and assuming you have 
the TCXO-3, what is the expected freq. stability expected?  The 
K3EXREF is published at 0.05ppm.  At 144-MHz, 0.05ppm would be 1.44x5 
=  7.2 Hz.

That is equivalent to the +6-Hz error of my new DEMI 144-28 
transverter using a 116-MHz xtal oscillator.  I see drift up to 11-Hz 
after one-minute key down at 50w.

The K144XV would have the stability of the TCXO-3 in transmit 
(0.5ppm) which probably will drift only a few Hz at worst (based on 
my experience with the K3EXREF+TCXO-3 on 50-MHz where transmit drift 
was not more than 3-4 Hz total error).  The TCXO-3 plus K144RFLK 
without the K3EXREF would have 0.5ppm or up to 70-Hz at 144-MHz (by 
my calculation).

 From that, I would encourage anyone that is planning to run digital 
modes like WSJT on 2m to install the K3EXREF with the K144RFLK.  You 
want to maintain <25Hz drift on these modes.  We often run the WSJT 
sw with only a 25-Hz decoding window so if you signal drifts outside 
that it will affect detection.  To be fair I see many 2m eme signals 
that drift up to 50 Hz in one minute transmission.  I just open the 
decoding window to 50 or 100Hz for them.  Note: WSPR is the most 
demanding of the digital modes on freq. stability.


73, Ed - KL7UW, WD2XSH/45
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