Re: WWV Broadcast Outages

[Royce Williams]

On Mon, Mar 6, 2017 at 5:12 AM, Andrew Gallo  wrote:
>
> On 3/6/2017 3:55 AM, Majdi S. Abbas wrote:
>>
>> On Wed, Feb 22, 2017 at 04:59:53AM -0800, Hal Murray wrote:
>>>
>>> Any suggestions for gear and/or software that works with WWV (or CHU)?
>>> Or general suggestions for non GPS sources of time?
>>
>> Hey Hal!
>>
>> In North America, WWV and CHU are pretty much it for accessible
>> backups these days.  Unfortunately time and frequency distribution is a
>> niche that tends to get neglected (if not actively gutted) in US
>> budgets.
>
> Agreed, but I'll share this- the recent FCC CSRIC V had a working group (4B) 
> that studied the reliability of time and frequency distribution.
> https://www.fcc.gov/about-fcc/advisory-committees/communications-security-reliability-and-interoperability
>
> It may be of interest.

Specifically, the "Network Timing Single Source Risk Reduction - Final
Report" part:

https://transition.fcc.gov/bureaus/pshs/advisory/csric5/WG4B_FinalReport_122116.docx

My summary of its points:

* Analysis of vulnerabilities in the "supply chain" of GPS

* Assertion that GPS mitigations and alternatives are needed to reduce risk

* Some likely characteristics of good mitigations and alternatives

* A list of potential alternatives, their features, and their current
state (L2C & L5 GPS, Galileo & GLONASS, LEO satelltes, commercial RF,
antenna pattern optimization, NMA on L2C, sync over fiber, eLORAN,
other RF sync, terrestrial beacons, and hybrid DME)


>From the executive summary:

The U.S. communications sector relies heavily on the Global
Positioning System (GPS) to provide network time. GPS is a widely
available, extremely precise timing source that is used across
multiple infrastructure sectors. However, given the high dependence of
the communications sector on GPS, the Federal Communications
Commission (Commission) is interested in identifying ways to increase
the resilience of communications networks by exploring complementary
or backup solutions that could be employed to offer similar time
precision as GPS in the event that GPS signals are lost. These
solutions also need to be completely independent of GPS to
significantly reduce any risk. This report addresses the problems
associated with relying on GPS solutions, the ideal technical
characteristics for systems to backup or supplement GPS, and our
recommendations for possible backup solutions by the communications
industry and others reliant on communications network timing sources.

Royce

Re: WWV Broadcast Outages

[Andrew Gallo]

On 3/6/2017 3:55 AM, Majdi S. Abbas wrote:

On Wed, Feb 22, 2017 at 04:59:53AM -0800, Hal Murray wrote:

Any suggestions for gear and/or software that works with WWV (or CHU)?
Or general suggestions for non GPS sources of time?

Hey Hal!

In North America, WWV and CHU are pretty much it for accessible
backups these days.  Unfortunately time and frequency distribution is a
niche that tends to get neglected (if not actively gutted) in US
budgets.



Agreed, but I'll share this- the recent FCC CSRIC V had a working group 
(4B) that studied the reliability of time and frequency distribution.

https://www.fcc.gov/about-fcc/advisory-committees/communications-security-reliability-and-interoperability

It may be of interest.

Re: WWV Broadcast Outages

[Majdi S. Abbas]

On Wed, Feb 22, 2017 at 04:59:53AM -0800, Hal Murray wrote:
> Any suggestions for gear and/or software that works with WWV (or CHU)?  
> Or general suggestions for non GPS sources of time?

Hey Hal!

In North America, WWV and CHU are pretty much it for accessible
backups these days.  Unfortunately time and frequency distribution is a 
niche that tends to get neglected (if not actively gutted) in US
budgets.

> Dave Mills had a driver in ntpd that used a PC audio port to listen to WWV.  
> I don't know anybody who ever used it.  I think there was code to tell some 
> brand of receiver with a serial/USB port how to change frequencies so you 
> could use the one that worked best for that time of day.

You do now.  The WWV and CHU audio drivers work fine.  If you
want the auto-tuning functionality, you need to use an Icom receiver
that supports their CI-V protocol.  (This can be a full fledged tabletop
like the R-75, or a more compact receiver like their PCR-100 or 1000.  
Some of these are no longer produced, but they're easy to come by on the
secondary markets.  I picked up multiple PCR-100s off eBay at $25 ea a
while ago.)

You can always use any shortwave receiver, and just tune it to a
good frequency.  There are also kit and prebuilt 10 MHz receivers out 
there in the $30-$40 range which will work.  You accept a slight loss in
daily coverage by selecting a compromise frequency, but it's better than
nothing and independent of GPS.

If you (or anyone else on NANOG) needs some help getting the
audio refclocks working; drop me a line.

> There used to be WWVB (60 KHz) receivers.  The good ones phase locked 
> to the carrier.  The general rise in EMI made those close to useless 
> in most locations.  NIST finished the job when they changed the 
> modulation format a few years ago.  As far as I know, there aren't any 
> replacements for the old gear that take advantage of the new modulation 
> format.  GPS works too well.

It's not so much that GPS works so well, as there's no way to
produce a commercial receiver that uses the enhanced format.  By gifting
the developed IP back to the developer as part of the SIPR grant, it is
all sitting under a patent umbrella.  Unfortunately, the startup that 
developed it appears to have failed (at least, they've mostly vanished,
folks seem to have moved on, and they're late on corporate reports at 
this point.) -- leaving the new format only usable by hackers and not
something that can be rolled into a commercial timing receiver.

My biggest beef with the new format was the rollout, 5 years ago
now, before a commercial receiver was available on the market.  I'm not
sure why NIST has stuck with it.

> There are some boxes that recover the time from nearby cell phone towers.  I 
> think they will stop working as the towers get upgraded to the newer 
> protocols that use a different form of timing.  That will probably take many 
> years.  But the cell phone towers depend on GPS.  (You can ususlly spot the 
> conical antenna(s) if you look around a bit.)

CDMA was only ever good to +/- 10ms anyway, at least any of the
boxes I ever used.  You can actually outperform it with classic WWV or CHU,
and those get you a real backup, rather than an indirect dependancy on
GPS.

--msa

Re: WWV Broadcast Outages

[Hal Murray]

"Majdi S. Abbas"  said:
>   That said, I and many others "still use" WWV -- there aren't exactly a
> surplus of suitable backup methods to GPS these days. 

Any suggestions for gear and/or software that works with WWV (or CHU)?  Or 
general suggestions for non GPS sources of time?

Dave Mills had a driver in ntpd that used a PC audio port to listen to WWV.  
I don't know anybody who ever used it.  I think there was code to tell some 
brand of receiver with a serial/USB port how to change frequencies so you 
could use the one that worked best for that time of day.

There used to be WWVB (60 KHz) receivers.  The good ones phase locked to the 
carrier.  The general rise in EMI made those close to useless in most 
locations.  NIST finished the job when they changed the modulation format a few 
years ago.  As far as I know, there aren't any replacements for the old gear 
that take advantage of the new modulation format.  GPS works too well.

There are some boxes that recover the time from nearby cell phone towers.  I 
think they will stop working as the towers get upgraded to the newer 
protocols that use a different form of timing.  That will probably take many 
years.  But the cell phone towers depend on GPS.  (You can ususlly spot the 
conical antenna(s) if you look around a bit.)



-- 
These are my opinions.  I hate spam.

Re: WWV Broadcast Outages

[Majdi S. Abbas]

On Tue, Feb 21, 2017 at 11:21:09AM -0500, Sean Donelan wrote:
> If any network operators still use WWV for time synchronization.

I wouldn't expect this to cause any serious synchonization
problem; anyone using HF for time has to have the ability to hold
over for a miniumum of several hours anyway due to the vagaries of
normal shortwave propagation.  (Even 24-48 hour disruptions aren't
uncommon after a large solar event.)

That said, I and many others "still use" WWV -- there aren't
exactly a surplus of suitable backup methods to GPS these days.

But if anyone needs it, consider using the fine HF time
service provided by our friendly neighbors to the north:

http://www.nrc-cnrc.gc.ca/eng/services/time/short_wave.html

--msa

WWV Broadcast Outages

[Sean Donelan]

If any network operators still use WWV for time synchronization.

Due to an electrical up-grade, Radio Station WWV will be off the air on 
all frequencies on February 21 and 22, 2017. The outages will occur 
between 7:00 AM and 5:00 PM Mountain Standard Time, and will not exceed 8 
hours in duration each day.


https://www.nist.gov/pml/time-and-frequency-division/time-services/wwv-broadcast-outages