Hi Dick, There may be a little misunderstanding as to what "locked" means in this implementation. It isn't the same as phase locking an oscillator to a high standard reference that's true. On the other hand it is more than good enough for almost any HF application, and it has the huge benefit of not risking degrading the excellent phase noise characteristics of the K3' synthesiser.
Basically any accurate 10 MHz source (calibrated occasionally) that is temperature stable like an ovened crystal oscillator or a Rubidium source could be used for this, however many already have a GPSDO and there are plenty surplus ones as well as fairly inexpensive ones that would be useful for other purposes that can be obtained. Some people including myself have a thing about frequency accuracy, and it is easy to become over obsessive about it ;-) I am more concerned with limiting any frequency drift so that narrowband digital modes are not degraded in sensitivity, especially at VHF and above. 73 from David GM4JJJ > On 11 Mar 2016, at 18:31, Richard W. Solomon <w1...@earthlink.net> wrote: > > OK, so folks are tossing the term “locked” around without realizing it is > wrong. > > Then all this talk of using a GPSDO is irrelevant, it will not do any good to > use one. > > Thanks for the education. > > 73, Dick, W1KSZ > > From: David Anderson [mailto:gm4...@yahoo.co.uk] > Sent: Friday, March 11, 2016 11:07 AM > To: Richard W. Solomon > Cc: Elecraft@mailman.qth.net > Subject: Re: [Elecraft] 10 MHz external reference - GPSDO > > Dick, > > I found the reference to that figure I quoted, it is in the K3EXREF manual: > > The K3EXREF option locks the K3's reference oscillator frequency to an > external 10 MHz source by automatically controlling the REF CAL function. > While locked to the external source, the K3’s reference oscillator frequency > is maintained within 2 Hz. Since the K3EXREF does not phase lock the K3’s > reference oscillator, the external 10 MHz source has no impact on the K3’s > phase noise performance. For best performance we recommend your K3 be > equipped with the KTCXO3-1 high stability (0.5 ppm typ.) reference > oscillator. > > > 73 from David GM4JJJ > > On 11 Mar 2016, at 16:55, Richard W. Solomon <w1...@earthlink.net> wrote: > > I am a tad confused over this issue. Perhaps I need to read up on how > Elecraft > controls frequency. > > My understanding on a "Locked" frequency would infer that the result would > be > a LOT closer than 2 Hz @ 10 MHz. > > Is there a detailed description of the process somewhere that I could read ? > > 73, Dick, W1KSZ > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
