[time-nuts] Alternate frequency sources : DVB-T and ISDN?

[Bill Hawkins]

Well, if you're gonna be practical about it, the EMPs that take out GPS
will convert a lot of silicon chips to sand. This will bring transportation
to a halt - aircraft, cars, trains (at least their signaling systems), and
boats (navigation if not engine controls). This could put water, food, and
energy in short supply, along with manufacturing processes that rely on
computers for control. Telephone and radio communication would also go away,
except for the very few battery-powered vacuum tube sets.

Precision time and frequency would probably drop to last on your priority
list.

Have a nice day.

Bill Hawkins


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of phil
Sent: Tuesday, November 24, 2009 3:02 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Alternate frequency sources : DVB-T and ISDN?

>> Speaking of alternate sources: Has any time-nut considered using the ISDN
>> telephone network [2]?
>
> I think ISDN is finally dead here in Sweden. I can check if my ISDN 
> connection is out for good. However, I wonder if the modern replacement to

> ISDN, such as ADSL is actually synchronised. It too uses OFDM/COFDM 
> transmission and provides pilot-tones.
>
>>        Chris


Should you have a catastrophic failure of the gps system and Loran is dead 
and buried, the only true source for time/frequency will be from the 
respective government sites. In the US it would be WWVB, WWV, NTS 
(internet), and acts (Telephone).

I think most of you are forgetting that the bulk of the alternate sources 
being discussed derive their time/frequency guidance from gps. Cell towers, 
tv stations, tv networks, and the like will be left to their local timebases

until an alternate correction scheme is developed and applied. The major tv 
networks "had" cesium standards, and I would think they still do but most 
others will be left to drift until they can be upgraded to an alternate 
guidance system.

Another thought, if that "catastrophic" failure should take out the gps 
satellites, chances are it could take out the tv satellites too. Then all 
that's left is copper, fiber, radio, and microwave sites.

 If you need a reliable backup, perhaps it's time to dust off the old wwvb 
receivers and integrate them with these cheap rubidium standards. Perhaps 
now they will start bringing more than 50 bucks on epay!

Phil 


_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.