4 ms·

Hard to justify the utility of the WWVB station with the coexistence of 4 going on 5 independent GPS systems along with telephone/cellular and internet systems.

Hard to justify the utility of the WWVB station with the coexistence of 4 going on 5 independent GPS systems along with telephone/cellular and internet systems. Pull is preferable over push given the use is not to be a canary; jamming a single time source is not strategically relevant. If it was there would be security at the station, but as is in a residential area some one could walk up with a power tool and take it down.

hasmanean 5y ago
One system is land based. The others are space based. The world needs redundancy especially in the presence of solar flares that can knock out satellites.
throw0101a 5y ago
> Hard to justify the utility of the WWVB station with the coexistence of 4 going on 5 independent GPS systems. All those GNSS systems use the same frequencies that can easily be jammed: * https://gssc.esa.int/navipedia/index.php/GNSS_signal https://gssc.esa.int/navipedia/index.php/GNSS_signal Even the US government themselves recognizes the importance of resiliency: * https://insidegnss.com/dot-report-on-backup-pnt-technologies-finds-nextnav-performs-best-calls-for-synthesis-and-synergy/ https://insidegnss.com/dot-report-on-backup-pnt-technologies... * https://www.transportation.gov/briefing-room/us-dot-releases-complementary-positioning-navigation-and-timing-pnt-and-gps-backup https://www.transportation.gov/briefing-room/us-dot-releases...
breput 5y ago
Shutting it down would have made every single existing radio controlled clock e-waste, overnight. And not just random wristwatches and wall clocks, but school and industrial clocks. None of these will work with GNSS signals.
- potiuper 5y ago
  That's the point, to stop creating this e-waste. If those applications are critical, then the owners should never have bought vulnerable radio controlled clocks in the first place.
  - gumby 5y ago
    Your assertion doesn’t even make sense. The hardware (wall clocks) could be older than gps. And gps is not only more expensive to receive, it’s harder too (most of those clocks would be indoors). And the wwv signal is far more robust than gps.
    - potiuper 5y ago
      Radio clocks are vulnerable to signal loss and spoofing regardless if it is GPS, cellular, or HF. If the time accuracy is critical, then the time signal should be delivered by wire to device, especially indoors. Wall clocks should have a manual way to set the clocks given there has never been a guarantee to receive the WWV signal. If expense is the concern along with wireless capability, then an integrated 2.4GHz SoC could be used that costs pennies; https://www.beaglesoft.com/radsynreceiver.htm https://www.beaglesoft.com/radsynreceiver.htm appears to cost hundreds.
      - gumby 5y ago
        Well of course you can’t design against every eventuality, just the most likely. > If expense is the concern, ... costs pennies. I don’t suppose you’ve ever worked on a product where a couple of pennies would sink the BOM. Not to mention antenna design and cost.
iamhamm 5y ago
You may have arrived at this view due to lack of visibility on what WWV does. WWV also provides: - stable reference frequencies for maritime and aviation radio and also for terrestrial radio tuning - space weather alerting for radio system operators - GPS system status updates for maritime and aviation - High accuracy intervals and UT1 corrections (which used in conjunction with GPS for highly accurate position measurements) Despite sounding like some legacy thing, this is a highly active system used by a lot of folks. I built a stratum 1 NTP system for power grid a few years ago using EndRun high accuracy appliances and we used GPS and WWV as the sources. https://tf.nist.gov/stations/iform.html https://tf.nist.gov/stations/iform.html
- breput 5y ago
  The reference frequency part is very important. There is a lot of test gear that relies on a 10 MHz signal for calibration.
  - squarefoot 5y ago
    Very accurate reference frequencies can be obtained by syncing an oscillator to a GPS receiver clock output (0). I'm however all for maintaining traditional shortwave (not just time and frequency) radio stations on, for being much easier to receive and harder to control by governments. 0: https://en.wikipedia.org/wiki/GPS_disciplined_oscillator https://en.wikipedia.org/wiki/GPS_disciplined_oscillator
mikewarot 5y ago
Yes, we could have a partial backup to a 1.7 Billion/Year program for less than 0.007 Billion per year, but no.. that's too expensive?
- potiuper 5y ago
  Any program cost has to be evaluated with respect to its benefits, even if it insignificant in face of most government spending. The question is if the cost to have this backup to synchronize time over radio to increase the reliability within Broadcast Outage limits of WWV is less than the costs that would occur due to time drift with all of the existing systems being unavailable given their expected reliability.

hasmanean 5y ago

One system is land based. The others are space based. The world needs redundancy especially in the presence of solar flares that can knock out satellites.

throw0101a 5y ago

> Hard to justify the utility of the WWVB station with the coexistence of 4 going on 5 independent GPS systems. All those GNSS systems use the same frequencies that can easily be jammed: * https://gssc.esa.int/navipedia/index.php/GNSS_signal https://gssc.esa.int/navipedia/index.php/GNSS_signal Even the US government themselves recognizes the importance of resiliency: * https://insidegnss.com/dot-report-on-backup-pnt-technologies-finds-nextnav-performs-best-calls-for-synthesis-and-synergy/ https://insidegnss.com/dot-report-on-backup-pnt-technologies... * https://www.transportation.gov/briefing-room/us-dot-releases-complementary-positioning-navigation-and-timing-pnt-and-gps-backup https://www.transportation.gov/briefing-room/us-dot-releases...

breput 5y ago

Shutting it down would have made every single existing radio controlled clock e-waste, overnight. And not just random wristwatches and wall clocks, but school and industrial clocks. None of these will work with GNSS signals.

potiuper 5y ago
That's the point, to stop creating this e-waste. If those applications are critical, then the owners should never have bought vulnerable radio controlled clocks in the first place.
- gumby 5y ago
  Your assertion doesn’t even make sense. The hardware (wall clocks) could be older than gps. And gps is not only more expensive to receive, it’s harder too (most of those clocks would be indoors). And the wwv signal is far more robust than gps.
  - potiuper 5y ago
    Radio clocks are vulnerable to signal loss and spoofing regardless if it is GPS, cellular, or HF. If the time accuracy is critical, then the time signal should be delivered by wire to device, especially indoors. Wall clocks should have a manual way to set the clocks given there has never been a guarantee to receive the WWV signal. If expense is the concern along with wireless capability, then an integrated 2.4GHz SoC could be used that costs pennies; https://www.beaglesoft.com/radsynreceiver.htm https://www.beaglesoft.com/radsynreceiver.htm appears to cost hundreds.
    - gumby 5y ago
      Well of course you can’t design against every eventuality, just the most likely. > If expense is the concern, ... costs pennies. I don’t suppose you’ve ever worked on a product where a couple of pennies would sink the BOM. Not to mention antenna design and cost.

iamhamm 5y ago

You may have arrived at this view due to lack of visibility on what WWV does. WWV also provides: - stable reference frequencies for maritime and aviation radio and also for terrestrial radio tuning - space weather alerting for radio system operators - GPS system status updates for maritime and aviation - High accuracy intervals and UT1 corrections (which used in conjunction with GPS for highly accurate position measurements) Despite sounding like some legacy thing, this is a highly active system used by a lot of folks. I built a stratum 1 NTP system for power grid a few years ago using EndRun high accuracy appliances and we used GPS and WWV as the sources. https://tf.nist.gov/stations/iform.html https://tf.nist.gov/stations/iform.html

breput 5y ago
The reference frequency part is very important. There is a lot of test gear that relies on a 10 MHz signal for calibration.
- squarefoot 5y ago
  Very accurate reference frequencies can be obtained by syncing an oscillator to a GPS receiver clock output (0). I'm however all for maintaining traditional shortwave (not just time and frequency) radio stations on, for being much easier to receive and harder to control by governments. 0: https://en.wikipedia.org/wiki/GPS_disciplined_oscillator https://en.wikipedia.org/wiki/GPS_disciplined_oscillator

mikewarot 5y ago

Yes, we could have a partial backup to a 1.7 Billion/Year program for less than 0.007 Billion per year, but no.. that's too expensive?

potiuper 5y ago
Any program cost has to be evaluated with respect to its benefits, even if it insignificant in face of most government spending. The question is if the cost to have this backup to synchronize time over radio to increase the reliability within Broadcast Outage limits of WWV is less than the costs that would occur due to time drift with all of the existing systems being unavailable given their expected reliability.