Since some time I am working on a solution just for fun ( http://n2.nabble.com/KREF-EXT-Option-tc2461086.html#a2461086 ). My GPS-derived clock was built from VE2ZAZ design and it works fine ( it is also used for other purpose in lab). PLL is a ADF4001 programmed from a AVR ATtiny2313. So far the system is running stand alone with a VCXO external to the K3 since my KTCXO3 does not have a voltage control connection. It is certainly possible to modify the KTCXO3 to a VCTCXO but I didn´t dare to do that yet. Maybe Elecrafts supplier can provide such a beast?
If you are planning to use the K144XV as IF for higher order transverters it would be important to get this reference accuracy. 73 Jan Ian White GM3SEK wrote: > > David Pratt wrote: >>Page 17 of the K3 Owner's Manual (Rev D2) shows an SMA connector for >>"Input for external standard frequency reference" for which a KREF3-EXT >>option purports to be available eventually. I understand from what has >>been said earlier is that this will be for a 10MHz standard so you will >>need to use the 60kHz MSF signal to lock a 10MHz TCXO or use a GPS, >>Rubidium or Caesium standard. >> > > The schematic of the KSYN3 board shows a header (J4) with connections to > the 10MHz input, the 49.380MHz output from the existing oscillator > module and a V_ctrl line going back to the oscillator module. This > suggests that the KREF3-EXT module will have a phase-locked loop to lock > the oscillator to 10MHz. > > (Also on J4 is a mysterious "100Hz" bus which wanders around many other > areas of the K3... anyone know what that is?) > > However, phase locking to an external reference still doesn't mean that > the K3 will be precisely on frequency. Due to the internal arithmetic > of the K3's synthesis and mixing scheme, the frequency you see on the > display is not quite the frequency you actually get. As Wayne pointed > out on 17 November, "this translates to a VCO step size of about 0.5 Hz > on 160 m, 1 Hz on 20 m, and 2 Hz on 6 m. Other bands are between these > values." > > What the KREF3-EXT module should be able to deliver is complete freedom > from frequency drift, for almost all practical purposes. There could > also be great communication value in being able to lock a pair of K3s to > the same global GPS standard, even when they are half a world apart > > In the meantime, the K3 already has the most important kind of frequency > and phase locking - between its own two receivers for true diversity > reception. > > > -- > > 73 from Ian GM3SEK > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > -- View this message in context: http://n2.nabble.com/K3-REF-IN-tp4105110p4111112.html Sent from the Elecraft mailing list archive at Nabble.com. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
