Another 5 MHz HP was the 5360A
On Fri, Aug 2, 2013 at 6:14 PM, Bob Camp <li...@rtty.us> wrote: > Hi > > The math is pretty simple: > > The Q of quartz goes up as the frequency goes down. > > A crystal resonator's performance (Q) is limited by it's thickness to > diameter ratio. > > At some point the resonator design impacts the Q of the resonator more > than the Q of the raw quartz. > > Holders are available that will rationally hold a maximum diameter blank. > > It's the intersection of all of the above that implies a best solution. > The "sweet spot" is not just quartz, it's the combination of all of the > above. > > Change any of the above (like the holder) and you get another "sweet spot" > > ------------------------- > > Is that simple? Of corse not. Many things need to change to let you make a > high performance blank that's much bigger. Many things need to change to > keep the Q of the quartz the limiting factor. > > ------------------------- > > Why has it not been done? The drive in the marketplace is to smaller / > cheaper. This is totally the opposite direction from that. The investment > to make larger blanks goes at least back to the design of the gear that > grows quartz. What we have is "good enough", but it's far from the best we > could do. Quartz is not the limiting factor. > > Bob > > > > On Aug 2, 2013, at 7:52 PM, Tom Knox <act...@hotmail.com> wrote: > > > > > Interesting, I have heard for years from the senior Time and Freq > researchers I work with that 5MHz was a sweet spot. I will ask if there is > a reason and proven physics behind it but these are individuals that are > well grounded in science. They almost always multiply 5MHz if they needed > 10MHz etc. > > Perhaps I missed something. It wouldn't be the first time I was schooled > by the TimeNuts. > > Best Wishes; > > Thomas Knox > > > > > > > >> From: li...@rtty.us > >> Date: Fri, 2 Aug 2013 14:39:21 -0400 > >> To: time-nuts@febo.com > >> Subject: Re: [time-nuts] 5MHz x 10MHz > >> > >> Hi > >> > >> Quartz it's self has no "sweet spot". The only issue is how low you can > go in a specific sized crystal holder before you start to run into trouble. > A TO-5 crystal will have a different minimum frequency than an HC-40. > >> > >> Bob > >> > >> On Aug 2, 2013, at 2:30 PM, Mike Feher <mfe...@eozinc.com> wrote: > >> > >>> It was my understanding that this "sweet spot" was optimum a little > above 3 > >>> MHz, so, 3rd overtone crystals are used to generate a stable, low phase > >>> noise 10 MHz. Prior to that, 5 MHz was used and before that 1 MHz > 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 Tom Knox > >>> Sent: Friday, August 02, 2013 2:02 PM > >>> To: Time-Nuts > >>> Subject: Re: [time-nuts] 5MHz x 10MHz > >>> > >>> It is my understanding that Quartz has a sweet spot at 5MHz that makes > it > >>> ideal if the lowest possible phase noise and highest stability are > needed. > >>> > >>> Thomas Knox > >>> > >>> > >>>> Date: Fri, 2 Aug 2013 19:57:16 +0200 > >>>> From: mag...@rubidium.dyndns.org > >>>> To: time-nuts@febo.com > >>>> Subject: Re: [time-nuts] 5MHz x 10MHz > >>>> > >>>> Hi Euclides, > >>>> > >>>> On 02/08/13 18:31, Euclides Chuma wrote: > >>>>> Hi, > >>>>> > >>>>> Why any equipments use 5 MHz and others use 10 MHz reference > standard? > >>>> > >>>> There are some benefits (traditionally) in using 5 MHz over 10 MHz, > >>>> but > >>>> 10 MHz have become a common standard. The actual frequency isn't > >>>> really magic, but 5 MHz and multiples became somewhat standard in the > >>>> old MIL STD 188 for time-keeping, and it fit fairly well with what was > >>>> already in use. There are folks here that can correct me on massive > >>> details. > >>>> > >>>> Today 10 MHz is more common because, well, engineers then to be > >>>> following habits, and 10 MHz "sounds nice". I use 10 MHz mainly > >>>> because the application requires it, otherwise I use whatever > >>>> frequency fits my other needs, or what becomes easy to source. > >>>> > >>>> PS. Have not seen you post before, so welcome to time-nuts! > >>>> > >>>> Cheers, > >>>> Magnus > >>>> _______________________________________________ > >>>> 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. > > > > _______________________________________________ > > 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.
