[time-nuts] The 5MHz Sweet Spot

[Bob Camp]

Hi

Well what I’ve been going from is the information I was taught by the people who actually designed all those crystals back in the 40’s 50’s and 60’s.

Bob

On Nov 2, 2013, at 9:50 AM, Mike Feher <mfeher at eozinc.com> wrote:

> 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-bounces at febo.com [mailto:time-nuts-bounces at 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
> 
> 
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