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Hi Talking about rubidium standards. Does anyone have any experience with buying and using the EFRATOM LPRO-101 rubidium standard that seems to be readily available from the many Chinese sellers on Ebay? I am tossing up between the LPRO rubidium and the Thunderbolt GPS standard. The Thunderbolt makes a lot of sense since it does not depend on a tube that can wear out or go out of lock. Will Elecraft be producing both the frequency standard and the interface or just the interface? 73 Craig ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In a recent message, Craig <[hidden email]> wrote ...
> >I am tossing up between the LPRO rubidium and the Thunderbolt GPS >standard. The Thunderbolt makes a lot of sense since it does not >depend on a tube that can wear out or go out of lock. True, but it does assume that the GPS satellites will not be wiped out by a chain reaction caused by the conglomeration of space junk up there. >Will Elecraft be producing both the frequency standard and the >interface or just the interface? I doubt that Elecraft will need to supply a standard as there already exists several sources of those. We must be thankful of their intention to provide the KREF3-EXT interface. 73 -- David G4DMP Leeds, England, UK ------ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Craig-89
I guess I'm missing the reason for having such precision. How can it make sense to have a precision standard for a receiver that changes the tuned frequency when the DSP bandwidth is changed? Wes N7WS --- On Sat, 5/16/09, Craig <[hidden email]> wrote: > From: Craig <[hidden email]> > Subject: [Elecraft] Tr: K3 Ref connector > To: [hidden email] > Date: Saturday, May 16, 2009, 3:14 AM > > Hi > > Talking about rubidium standards. > > Does anyone have any experience with buying and using the > EFRATOM LPRO-101 rubidium standard that seems to be > readily available from the many Chinese sellers on > Ebay? > > I am tossing up between the LPRO rubidium and the > Thunderbolt GPS standard. The Thunderbolt makes a lot > of sense since it does not depend on a tube that > can wear out or go out of lock. > > Will Elecraft be producing both the frequency standard and > the interface or just the interface? > > 73 > Craig > > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ... [show rest of quote] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by David Pratt
I wonder if there is a way of using a cheap 60kHz radio controlled clock
receiver to phase lock an 'ordinary' 10MHz crystal osc. David G3UNA ----- > In a recent message, Craig <[hidden email]> wrote ... >> >>I am tossing up between the LPRO rubidium and the Thunderbolt GPS >>standard. The Thunderbolt makes a lot of sense since it does not >>depend on a tube that can wear out or go out of lock. > > True, but it does assume that the GPS satellites will not be wiped out > by a chain reaction caused by the conglomeration of space junk up there. > >>Will Elecraft be producing both the frequency standard and the >>interface or just the interface? > > I doubt that Elecraft will need to supply a standard as there already > exists several sources of those. We must be thankful of their intention > to provide the KREF3-EXT interface. > > 73 > -- > David G4DMP > Leeds, England, UK > ------ > ... [show rest of quote] ______________________________________________________________
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In reply to this post by Craig-89
I have bought items from fluke.l on eBay who sells them. He sells the
GPS-DO, the Efratom device, adn the one I bought which is an FE-5860A Rubidium frequency standard from him and hooked it up last night. I've found fluke.l to be responsive and honest, and he ships quickly. (If you are in a hurry, ask about shipping options.) Here is a report on what I've learned and done so far, and where to find more info, plus a few rants on what I'd like to do myself. If nothing else, I've been annoying my family and co-workers by saying things like, "Let me get back to you on that after I finish the modifications I'm making to my Rubidium atomic clock." So, if you really want to know about these, don't listen to me, but instead look at these resources: 1. There's a mailing list called time-nuts where people who actually understand them hang out, and 2. Connie http://www.k5cm.com/ runs a monthly frequency measuring test and they have a mailing list there as well. (I placed fairly high in the last ARRL FMT, though not at the top.) 3. If you order an FE-5680A, this page is very useful: http://www.dd1us.de/Downloads/precise%20reference%20frequency%20rev%200_4.pdf Here's what I've learned from the manuals and reference materials: A Rubidium reference oscillator uses a Rubidium bulb, which is heated and the resulting gas tested for light absorption in the presence of an external RF field in the 6 GHz range. The microwave signal is tuned in a feedback loop to look for the peak in absorption (a very small change on the order of 0.1%) and that locks the oscillator in the known frequency of 6 834 682 610.904 324 Hz. Another external field is used to change this slightly, but I'm not the person to explain the physics. A 136x divider brings this down to 50.566+ Mhz, so you wind up with what is essentially a very stable oscillator with low phase noise. This 50+Mhz signal is then used as the reference frequency for our old friend the AD9830A DDS chip, which can then be programmed via an internal microprocessor and RS232 to whatever frequency you want, within the Nyquist range and the output filter range. By default these come set for ~8Mhz (2^23 Hz, which is divided down to get a 1Hz output). In most of the surplus units, this signal isn't available externally, but only internally with a connector that looks like a Hirose U.Fl connector. (If anybody knows different, please let me know, as I already have a U.Fl to BNC bulkhead pigtail on order.) I used the default 8,388,608 Hz signal out to a test pin to calibrate my FCC-1 kit, which it turned out was already within 1Hz. I also tried using it to calibrate my K3 REF CAL, but I'd turned the K3 off earlier and it wasn't warmed up. What I'd like to do: once my connector pigtail arrives, I'll put it in the FE-5860A and make a stab a quick python program to read the frequency with fldigi's in Freq Cal mode and read the data from fldigi's remote XML interface and use the K3 RS232 to control the REF CAL setting. Of course, this hack would just automate a manual process, and doesn't provide a way to keep the K3 on frequency during TX. Leigh/WA5ZNU > Hi > > Talking about rubidium standards. > > Does anyone have any experience with buying and using the EFRATOM LPRO-101 rubidium standard that seems to be readily available from the many Chinese sellers on Ebay? > > I am tossing up between the LPRO rubidium and the Thunderbolt GPS standard. The Thunderbolt makes a lot of sense since it does not depend on a tube that can wear out or go out of lock. > > Will Elecraft be producing both the frequency standard and the interface or just the interface? > > 73 > Craig > > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ... [show rest of quote] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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