[time-nuts] ISS NTP operation problems.

[Bernd Neubig]

Björn,
you are correct. The link you have provided points to the actual and latest document of the Wassenaar Arrangement for so-called "Dual-Use" items.
This international agreement is transformed to National laws, which often include some amendments.
For the European Union it is  the COUNCIL REGULATION (EC) No 428/2009, which is regularly updated, latest on is the 
COMMISSION DELEGATED REGULATION (EU) 2020/1749.

BTAW: For time-nuts  the chapter 3.A.1.b is interesting, which covers microwave and millimeter wave items. 
Under sub-clause 3.A.1.b.10 limitations for phase noise of these items are defined as follows:

Oscillators or oscillator assemblies, specified to operate with a single sideband (SSB) phase noise, in
dBc/Hz, less (better) than -(126 + 20log10F – 20log10f) anywhere within the range of 10 Hz ≤ F≤ 10 kHz;
(F is the offset from the operating frequency in Hz and f is the operating frequency in MHz)

>From the technical viewpoint it does not make much sense to specify the phase noise limits with a slope of -20 dB/decade, while in practice (and theory) the slope close to carrier is -30 dBc/Hz. 

Not too seldom, it is not recognized that this rule is limited to microwave and millimeter wave oscillators. As the document does not define where "microwave" begins, this rule is sometimes applied to crystal oscillators below 200 MHz- which to my opinion is wrong, as microwaves are starting above 1 GHz or so. 

Regards
Bernd



-----Ursprüngliche Nachricht-----
Von: time-nuts [mailto:time-nuts-bounces at lists.febo.com] Im Auftrag von Björn
Gesendet: Samstag, 9. Januar 2021 06:04
An: Discussion of precise time and frequency measurement <time-nuts at lists.febo.com>
Betreff: Re: [time-nuts] ISS NTP operation problems.

Magnus, Warren,

ITAR are US rules for US products. Thus ITAR don’t apply for non US products. Has that changed?  

The original COCOM rule was “don’t do altitude above 18000m and speed exceeding 1000 knots. “

COCOM was then replaced by the Wassenaar agreement. I would have expected it the current list - but could not find it.

https://www.wassenaar.org/app/uploads/2020/12/Public-Docs-Vol-II-2020-List-of-DU-Goods-and-Technologies-and-Munitions-List-Dec-20-3.pdf

Did I miss it or has it moved somewhere else?


Kind regards,

     Björn 

Sent from my iPhone

> On 9 Jan 2021, at 00:13, Magnus Danielson <magnus at rubidium.se> wrote:
> 
> Warren,
> 
>> On 2021-01-08 23:15, Warren Kumari wrote:
>>> On Fri, Jan 8, 2021 at 11:40 AM Lux, Jim <jim at luxfamily.com> wrote:
>>>> On 1/8/21 6:59 AM, Magnus Danielson wrote:
>>> That is probably harder than it seems.  There's a lot of isolation 
>>> among systems on ISS - partly for safety, partly from history, 
>>> partly from institutional inertia. My payload on ISS (SCaN Testbed) 
>>> had a
>>> MIL-STD-1553 connection and a unidirectional Ethernet connection 
>>> (out of payload only). There's multiple GNSS receivers on ISS, but 
>>> not all are visible to an arbitrary payload - their output might get 
>>> packaged up as telemetry and store/forward sent to the ground via 
>>> episodic transmissions on the Ku-band system.  One of the 
>>> experiments on my payload was to actually try to measure the time 
>>> and position offsets between our radio(which had S-band Tx/Rx and 
>>> GPS receiver) and the various time sources on the Station.
>> I must admit that I'm very surprised that GPS receivers worked and 
>> were able to compute a fix.
>> The majority of GPS receiver chipsets have altitude and speed limits 
>> built in, both because of assumptions/discarding pathological 
>> results, but also because of ITAR and similar regulations. Were these 
>> special / licensed receivers which didn't have the "Erk, I think I'm on an ICBM"
>> logic?
> 
> These receivers do not follow the ITAR rules for sure. Just being 
> beyond
> 18 km is breaking one ITAR rule, being faster than 1 MACH is another 
> (don't recall the exact number for ITAR, but there aboutish).
> 
> But it works.
> 
> A fun special satellite measures the GPS satellite occulation 
> behavior, thus how the signal bends from below the horizon to just 
> above. That is an atmospheric measurement tool. For sure not ITAR compliant.
> 
> Cheers,
> Magnus
> 
> 
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