[time-nuts] Thermal effects on cables --> ADEV

[Bob Camp]

Hi

I do agree with their point that systematics will get buried in giant data blocks. 
What I’m not quite as sure of is the utility of even 300 sample blocks to spot
systematic issues.

Bob

> On Jan 13, 2017, at 1:08 PM, Scott Stobbe <scott.j.stobbe at gmail.com> wrote:
> 
> I think you might be overthinking their point, that if you plan to use an
> xDEV as a measure for state of health, don't use years worth of data.
> Otherwise it could be days before the xDEV visually changes.
> 
> On Fri, Jan 13, 2017 at 11:04 AM, Bob Camp <kb8tq at n1k.org> wrote:
> 
>> Hi
>> 
>> There’s an interesting comment buried down in that paper about limiting
>> ADEV to
>> < 300 samples per point. Their objective is apparently to better highlight
>> “systematic
>> errors”. I certainly agree that big datasets will swamp this sort of
>> thing. I’m not quite
>> sure that I’d recommend ADEV to find these things in the first place. My
>> guess is that
>> it’s the only spec they have to call the device good or bad in this case
>> …They don’t seem
>> to have Hadamard in their list of variances. If I was going after
>> systematics with a deviation,
>> that’s the one I’d use. Of course I probably would not use a something-dev
>> in the first place.
>> 
>> Bob
>> 
>> 
>>> On Jan 13, 2017, at 1:52 AM, Ole Petter Ronningen <opronningen at gmail.com>
>> wrote:
>>> 
>>> Hi, all
>>> 
>>> The question of phase shifts in cables pops up every now and then on this
>>> list - I stumbled across a good table of measured phase shifts with
>>> temperature in different cable types in this paper:
>>> http://www.ira.inaf.it/eratec/gothenburg/presentations/ERATEC_2014_
>> PresentationWSchaefer.pdf
>>> that I though would be of interest to others.
>>> 
>>> A quick summary given below, see pdf for full details. Lots of other
>>> interesting stuff in there also.
>>> 
>>> Values in ppm/K, for 10 Mhz except when otherwise stated. (The paper
>> gives
>>> values for 5, 10 and 100Mhz)
>>> 
>>> Huber-Suhner Multiflex 141: -6
>>> RG-223: -131.9
>>> Semiflex Cable: -11.5
>>> Huber-Suhner: -8.6
>>> Times Microwave LMR-240: -3.4
>>> Times Microwave SFT-205: 7.7
>>> Meggitt 2T693 SiO2: 30.6
>>> Andrew FSJ-1 (@5Mhz): 25
>>> Andrew FSJ-4 (@5Mhz): 10
>>> Andrew LDF-1P-50-42: 2.8
>>> Andrew LDF4-50A: 4.7
>>> Times Microwave TF4FLEX (@100Mhz):6.4
>>> Phasetrack PT210 (@100Mhz): 2
>>> 
>>> Ole
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