>From reading your past posts I must respect your opinion. Your are obviously >extremely educated on the subject. So why is there some disagreement in two >very knowledgeable groups?
Thomas Knox > From: li...@rtty.us > Date: Sat, 2 Nov 2013 18:44:18 -0400 > To: time-nuts@febo.com > Subject: Re: [time-nuts] The 5MHz Sweet Spot > > Hi > > The only thing that the 5 MHz 3rd crystal is “optimum” for is a holder that > will accept a 0.55” max diameter blank. > > Bpb > > On Nov 2, 2013, at 6:06 PM, Tom Knox <act...@hotmail.com> wrote: > > > Mike I think we must be talking to the same smart people. I think 5MHz was > > adopted over 3MHz simply because 5MHz multiplies to other commonly used > > frequencies with greater ease. I think the top frequency standards have > > evolved to 5MHz Third Overtone SC cut crystals for a reason. The evolution > > has gone on from the days of Tesla and improved greatly during the glory > > days of Quartz in the years leading up to atomic standards with countless > > hours of experimentation and research. Those lessons learned are constantly > > examined through the lens of the latest science. I may be wrong, but I > > have not heard of any extreme design prototype quartz oscillator with > > superior Phase Noise and Stability. Our house standard F1 a cesium fountain > > is used roughly one month every few months to characterize roughly 12 5071A > > cesium standards steering about 5 MHM 2010 cleaned up with a number of 8607 > > option 08 oscillator. (The equipment choices are not a recommendation or > > endorsement, and there are po > > ssibly m > > any product that could meet or exceed the performance of these fine > > products.) But the oscillators selected are 5MHz third Overtone SC cut. > > > > Thomas Knox > > > > > > > >> From: mfe...@eozinc.com > >> To: n1...@alum.dartmouth.org; time-nuts@febo.com > >> Date: Sat, 2 Nov 2013 09:50:50 -0400 > >> Subject: Re: [time-nuts] The 5MHz Sweet Spot > >> > >> Exactly - I mentioned this on here about 3 years ago and all of the > >> self-proclaimed geniuses poo-pooded it. I was told early in my engineering > >> career in the early 70's, by a very smart man, when I thought I had all of > >> the answers, that considering all of the trade-offs regarding performance, > >> around 3 MHz for a crystal is best, operating in the 3rd overtone mode, > >> hence the slow progression from the 1 and 5 MHz standards to 10 MHz. Now, > >> getting close to 70, I just see what I can learn from all the "smart" > >> people > >> on here, and keep quiet most of the time. Regards - Mike > >> > >> Mike B. Feher, EOZ Inc. > >> 89 Arnold Blvd. > >> Howell, NJ, 07731 > >> 732-886-5960 office > >> 908-902-3831 cell > >> > >> -----Original Message----- > >> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > >> Behalf Of David McGaw > >> Sent: Saturday, November 02, 2013 1:30 AM > >> To: Discussion of precise time and frequency measurement > >> Subject: Re: [time-nuts] The 5MHz Sweet Spot > >> > >> This all seems to be forgetting that the crystals are usually operated at > >> 3rd or 5th harmonic. The crystal in a 10811A is 10 MHz/3rd overtone. A > >> high quality 5 MHz/5th overtone crystal is really a 1 MHz fundamental, a > >> large piece of quartz. Running at a harmonic greatly reduces the influence > >> of the package. > >> > >> David > >> > >> > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts@febo.com > >> To unsubscribe, go to > >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
