[time-nuts] A beginner's question.

[ordnit]

Hi all,
I've been reading the ML for quite a long time. In the last weeks I 
managed to have some spare time to try some measurements, just to see 
how far is "reading" from "trying".

My lab is made up of a pair of GPSDO (UCCM modules with an external 
antenna and good sky coverage), a 53131A and a pair of quartz 
oscillators that were ripped from some scrap instruments.

Before trying to measure ADEV on a OCXO, I just wanted to see how deep 
is the noise floor with my setup. I read in old post (2012) that I could 
perform some tests using a the PPS output from the GPSDO, a power 
splitter and two coaxial cables of different lenght. So i put the 
counter in "t1 to T2" mode, auto-trigger on channel OFF and performed a 
very long ADEV analisys in TI mode.

Results I found were, in some ways, encouraging (to me):
1s	Sigma(tau) 	6.59E-10
10s			6.96E-11
100s			7.12E-12
1000s			7.01E-13

Tomorrow I'm going to perform more tests in fequency mode, by looping 
the 10MHz out of the counter, to its channel 1 input and performing ADEV 
analisys to. According to what I read, results should be quite different.

My question is: am I going on the right way? Are the tests I performed 
somewhat meaningful?

Thanks in advance.

Best regards.

adelmo

References:
Best counter setting for ADEV? - Time-nuts ML Oct 1 2012
Recommended parameters for Timelab ADEV analysis - Time-nuts ML Nov 15 2012
Measuring ADEV for a beginner - Time-nuts ML Nov 1 2014