Posted by
Elecraft mailing list on
Jun 06, 2018; 9:15pm
URL: http://elecraft.85.s1.nabble.com/K3S-XREF-GPSDO-recommendation-needed-tp7641686p7641758.html
This is lifted from an Elecraft document:
"ELIMINATING FREQUENCY JUMPS ON 2M WHEN USING THE K3EXREF AND K144XV PLL
LOCK MODULE"
<snip>
In order to lock to an external reference, the K3EXREF module counts the
frequency of the 49.380-MHz reference oscillator for about one second,
repeating about every four seconds. During this count time, the
circuitry draws about twice as much current as when it's static (it goes
from 7 mA to 15 mA). When it's drawing more current, it slightly
decreases the supply voltage to the reference oscillator, causing a
small frequency shift observable at 2 meters and possibly even on 6 meters.
<snip>
The mod is simple to apply.
Regards,
Mike VP8NO
On 06/06/2018 16:17, Clay Autery wrote:
> Does anyone have any idea how often that "check and nudge" procedure is
> done or better the logic behind how it is determined when to make a
> correction? I assume it is implemented in firmware.
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