[time-nuts] General Recommendation?

Bob kb8tq kb8tq at n1k.org
Mon Apr 16 08:29:41 EDT 2018


Hi

Like most things in life, what you want and what you can afford generally are
in opposition to each other :) 

The TimePod *is* the beast to use. A lot of us would love to get one at a “good 
price”. They sell for $10K and up from Microsemi when bought new. Exact price
varies with the options enabled and whatever sale they might be running at the 
time. 

Everything else on the list will struggle at 0.1 seconds in terms of any sort of 
accuracy close to what you are after. At 1 second, the DMTD will do a pretty 
good job, with some constraints on the signals you are looking at (all at exactly
10 MHz). 

Often the “what to compare to” problem is addressed with multiple references. 
Maybe a good OCXO close in and a Cs standard further out. You probably will 
get past 1,000 seconds fairly quickly. The “what does the next point look like” 
bug is a dangerous one :)

If you go back in the archives (or on the NIST Frequency & Time site) they did 
a “DIY TimePod: with an off the shelf SDR. The results were quite good and the 
cost was not to bad. I’ve always been a bit surprised that none of us have gotten
something like that running in our basement.  Can you do it with a $300 SDR 
board? Who knows ….

Lots of options ….

Bob

> On Apr 15, 2018, at 11:59 PM, AC0XU (Jim) <James.Schatzman at ac0xu.com> wrote:
> 
> I would like to make time stability measurements of various clock sources over a time range from 0.1 sec to 1000 sec and down to as much below 10^-12 as I can afford. Mainly I am interested in 10 MHz but also would like to be able to test stability and phase noise of synthesizers at higher frequencies (up to maybe 300 MHz or so).
> 
> I do not have a hydrogen maser and I am aware of the need for a stable reference clock.
> 
> My question is what device would be best for this purpose:
> 
> 1) Agilent 53230A
> 
> 2) HP 5370B
> 
> 3) Timepod (and is it possible to purchase one and if so how?)
> 
> 4) Some other device such as has been mentioned in other postings (W.J. Riley, etc.)
> 
> My supposition is that #1 and #3 cost about the same and #2 is considerably cheaper. All three are supported by  Timelab.
> 
> Don't think that I can afford the Microsemi 5120A or 5125A.
> 
> Not understanding the tradeoffs, I would appreciate some advice.
> 
> Thanks!
> 
> Jim
> 
> 
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