[time-nuts] Symmetricom X72
wb6bnq at cox.net
Sat Jul 24 16:20:42 EDT 2010
You got to be kidding ?
I am guessing, from your comments, that you need to do a bunch more reading and
pondering on the subjects of stability, accuracy and making those measurements.
Especially before tossing the FEI-5680's in the trash.
The FEI-5680A is a nice unit, you just have to understand what you have and how
to apply it. Assuming that the FEI-5680 is working correctly, it will be more
stable then most crystal oscillators found in the all but the very higher quality
In comparison to your TCXO, the FEI-5680 would be 3 orders of magnitude (i.e., 3
more decimal places or a 1000 times) more stable. And likely a hell of a lot
closer to the proper reference too.
Until you have a measurement system that is known to be more accurate then the
FEI-5680, there is no way to say it is a mistake. So, two primary components are
at hand here; first being stability and the second being accuracy. Even if it is
not SPOT on accurate with a world reference does not make it UN-usable as
stability would be the more sought after parameter in any case.
So, I disagree with your premise,
> Hello Bob,
> What would you recommend? I already have three FE-5680A Rb standards (which
> I'm quickly learning likely aren't worth the powder to blow them to (*insert
> your own word here*). Okay, that was probably my first mistake (thoughts?).
> My frequency counter is one I built from a kit from aade.com that has the
> TCXO option (although I had to tweak it myself so I have NO idea how close
> it is to any accuracy or precision). I have access to some really nice HP
> counters at work so that's my next step is to try one of those. My DFD4
> measured the output of one of my 5680A's to 10.000.007 MHz after about a 10
> minute warm-up. I don't know which one is off. Reading the specs on the
> 5680A's before I bought them looked like they were pretty decent. I'm
> So, what "reasonably priced" Rb standard would you recommend?
> Should my next step in this process be a Trimble Thunderbolt? Am I starting
> ----- Original Message -----
> From: "Bob Camp" <lists at rtty.us>
> To: "Discussion of precise time and frequency measurement"
> <time-nuts at febo.com>
> Sent: Saturday, July 24, 2010 9:31 AM
> Subject: Re: [time-nuts] Symmetricom X72
> > Hi
> > At least looking at the spec sheet it's not really very impressive.
> > Bob
> > On Jul 23, 2010, at 11:06 PM, Heathkid wrote:
> >> Hello. Does anyone have any experience with the Symmetricom X72?
> >> Thanks...
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