[time-nuts] HP10811 vs 00105 OCXO

KA2WEU at aol.com KA2WEU at aol.com
Sat Aug 8 19:21:13 EDT 2015


How good or bad is the 10811 and which one on   ebay   is a better choice ? 
I am looking for a very goo 5 MHz crystal oscillator  with documentation .
 
Thanks, Ulrich N1UL 
 
 
In a message dated 8/8/2015 7:16:37 P.M. Eastern Daylight Time,  
kb8tq at n1k.org writes:

Hi

Ok, so John’s observation was the correct one. The data  we are looking at 
is *not* the
performance of the OCXO’s but the strange  behavior of the counter at short 
ADEV Tau’s. 

Sorry for my bashing your  poor 10811.

Bob

> On Aug 8, 2015, at 12:25 PM,  timeok at timeok.it wrote:
> 
> Hi all,
> 
> I try to  ansver to all you:
> 
> Luciano, how was the blue trace taken? Is  this from your DMTD project? 
If so, it's looking promising.
> The green  and magenta traces are definitely in the right ballpark for 
measurements on a  5370-class counter. At 3E-11 @ t=12s the magenta trace is 
optimistic but not  outrageously so, while the green trace looks exactly like 
I'd expect for a  typical 10811 measured on a 5370. The observed noise is 
due entirely to the  counter until about t=200s. We see a glimpse of the 
10811's typical ADEV at  about 250 seconds, just before either drift or ADEV 
uncertainty causes the  trace to turn upwards. A longer run would be needed to 
distinguish between  these two situations.
> 
> -- john, KE5FX
> Miles Design  LLC
> 
> r: no, all the measurements are taken using an  HP53132A  in frequency 
mode. The difference can be the gate time. Using 1  second the resolution is 
lower than using 2 Second that permit the max  counter  resolution.
> 
> Hi
> 
> Well an  un-stated assumption of mine was that they all came from the 
same measurement  system and that it
> had the same floor under all  circumstances….
> 
> Bob
> 
> r: all the measurements  are under the same conditions except for the 
gate time of the counter.
>  
> Hi Luciano,
> 
> Can you give me the link to your ADEV  posting image about 10811 vs 105 
oscillators?  I had it and now can't  seem to find it.  I wanted to look at 
your plots as I read John Miles'  comments.  Many thanks.  
> 
> I have two very high  performing HP10811-60109 OCXO units which I got 
from Corby. 
> 
>  Many thanks.
> 
> Jim Robbins
> N1JR
> 
> r:  Jim, I will load soon some files on my site. The 105B I have is a 
fantastic  exception, unfortunately it have a defect, may be a bad  solder 
inside  cause randomly a phase jump and return to the original phase trend, so 
all The  long term ADEV are distorted by this problem I have to fix.
> 
>  Tom VB, i will do all the cross measurements on 10811, 00105 and 
rubidium I  have and i will upload they but I need time to do this.
> Unfortunately  I have only the HP53132A as TIC and my best reference are 
four HP5065A. I  normally use the counter function because the TI function 
on 1 PPS have 100  time less resolution.
> Will be interesting doing also the Phase noise  tests. I will do it.
> please see:  
http://www.timeok.it/files/time_and_frequency_house_standard_201r.pdf
>  
> Luciano
> www.timeok.it
> 
> 
> 
>  
> 
> On Sat 08/08/15 02:23 , Bob Camp <kb8tq at n1k.org>  wrote:
> 
>> Hi
>> 
>> Well an un-stated  assumption of mine was that they all came from the 
same
>>  measurement system and that it
>> had the same floor under all  circumstances….
>> 
>> Bob
>> 
>>> On  Aug 7, 2015, at 5:21 PM, John Miles  wrote:
>>>  
>>>> Hi
>>>> 
>>>> If that data  is correct, then the 10811 you have is defective.
>>>>  Bob
>>> 
>>> Well... some of the data is reasonable  for a scenario where a counter 
is
>> being used to measure  OCXOs.
>>> 
>>> Looking at the ADEV plot, I'd say the  blue trace (HP105B vs 5065A) is
>> the most questionable one if it  came from a standalone TIC or frequency
>> counter, because 7E-12 @  t=1s isn't achievable with most counters under
>> most circumstances.  A Wavecrest box can measure at that level if it's 
set
>> up  _perfectly_ to take bursts of 100+ wrap-free averages within a  small
>> fraction of the t0 interval. It might also be doable with an  HP 5370A/B
>> under similar conditions, but I'd have less confidence  that the 
averaging
>> isn't distorting the measurement. So while It  looks like a valid
>> measurement of an OCXO with some minor  crosstalk or other external
>> interference, that may just be a  coincidence.
>>> 
>>> Luciano, how was the blue trace  taken? Is this from your DMTD project?
>> If so, it's looking  promising.
>>> 
>>> The green and magenta traces are  definitely in the right ballpark for
>> measurements on a 5370-class  counter. At 3E-11 @ t=12s the magenta 
trace is
>> optimistic but not  outrageously so, while the green trace looks exactly
>> like I'd  expect for a typical 10811 measured on a 5370. The observed 
noise
>>  is due entirely to the counter until about t=200s. We see a glimpse of  
the
>> 10811's typical ADEV at about 250 seconds, just before either  drift or 
ADEV
>> uncertainty causes the trace to turn upwards. A  longer run would be 
needed
>> to distinguish between these two  situations.
>>> 
>>> -- john, KE5FX
>>>  Miles Design LLC
>>> 
>>> 
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