[time-nuts] 5MHz x 10MHz

[Tom Knox]

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: lists at rtty.us
> Date: Fri, 2 Aug 2013 14:39:21 -0400
> To: time-nuts at 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 <mfeher at 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-bounces at febo.com [mailto:time-nuts-bounces at 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: magnus at rubidium.dyndns.org
> >> To: time-nuts at 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
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