Hi Gary, Because the K3 only -frequency- locks the frequency to within about 2Hz you won't notice any difference between them. Similarly because the K3 TCXO isn't -phase- locked to the external reference any phase noise on the reference won't affect low phase noise of the synthesiser in the K3.
So buying a kilobuck reference isn't going to gain you anything at all. The BG7TBL or the Leo Bodnar unit would be my choice. (I have both here and a Z3801A) . The Leo Bodnar being a nice low power consumption unit, and a lot more versatile than just a 10 MHz GPSDO. It has many other uses around the shack, covering up to 800 MHz. 73 from David GM4JJJ > On 11 Mar 2016, at 12:53, Gary Smith <[email protected]> wrote: > > I appreciate the replies to my question about sourcing a 10 MHz > external reference for my K3s. I didn't realize I needed more than > the K3EXREF to gain this accuracy and thanks to these replies, I now > better understand what will and what will not work. While I would > prefer to be able to buy a satisfactory GPSDO or kit from Elecraft, > it isn't an option at this time and not knowing if one is on the > Horizon, I must look elsewhere to find one. > > What makes it a more difficult choice is understanding what values > are sufficient and what is excess; some of these devices are in the 4 > figures and some used are less than $40. I was about to buy a $40 > used TCVCXO but learned they need to be recalibrated to maintain > their precision and I having no equipment to do this, one of the more > expensive options apparently is a better solution. > > Apparently the low cost GPSDO are an affordable way to go for long > term accuracy but which one to get? Some apparently have jitter from > poorly isolated interference due to the proximity of their 1pps > Square wave functions but is that jitter something to affect their > function as a frequency standard for the K3/K3s, I have no idea. Is > there an advantage in accuracy by using the GPSDO linked below over > the BG7TBL versions from China? $226 & needing antenna and power > supply for low jitter vs $150 for everything but with higher jitter? > Is a square wave output as useful as a sine wave, both are available > in the BG7TBL versions. For an external reference function with the > radio, what is excess? I have no idea. > > Apparently the components in the BG7TBL versions change due to their > supply of surplus components; the versions are the manufacturing > date, and not all work identically because of this. But does it > matter, is the least desirable GPSDO still adequate to do this job > properly? Engineering is not my field and there's a lot to sift > through in reading peoples discussions and opinions when most of the > comments are not directed to effectiveness with the K3/K3s. > > There are other options available but apparently the prices have gone > up recently and some once viable options are now not available or > highly priced, even when used. If Elecraft is not going to make an > option available for purchase, what would probably be helpful would > be a listing here or on someone's page, of what kind of affordable > units are ideal for the 10 MHz reference source and what is > un-necessary overkill. > > Thanks again for the replies, its always fun to learn new things. > > 73, > > Gary > KA1J > > >> Take a look at this GPSDO >> <http://www.force12inc.com/products/gps-locked-precision-frequency-reference-low-jitter-gps-clock-450-hz-to-800-mhz-output.html>. >> >> Needs 13-15 VDC and a powered GPS antenna, but it is plug and playon any >> frequency from 450 KHz to 800 MHz, with software-adjustable output level. >> >> 73, Pete N4ZR >> Download the new N1MM Logger+ at >> <http://N1MM.hamdocs.com>. Check >> out the Reverse Beacon Network at >> <http://reversebeacon.net>, now >> spotting RTTY activity worldwide. >> For spots, please use your favorite >> "retail" DX cluster. >> >>> On 3/9/2016 12:37 PM, Gary Smith wrote: >>> I ordered the K3EXREF and thought it was the oscillator itself which >>> would provide the external signal source to the K3s. I thought this >>> was all I was going to need but I see now that is not the case. >>> Looking on the Elecraft order page, they don't sell a reference >>> source. >>> >>> What external 10-MHz reference signal source might I find get that is >>> not terribly expensive that will do the proper job and allow me to >>> get this working? >>> >>> Thanks & 73, >>> >>> Gary >>> KA1J > > ______________________________________________________________ > 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 > Message delivered to [email protected] ______________________________________________________________ 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 Message delivered to [email protected]
