[time-nuts] Nutty time-nuttery with WWVB

Bob Camp kb8tq at n1k.org
Thu Nov 10 17:37:35 EST 2016


> On Nov 10, 2016, at 4:52 PM, Ruslan Nabioullin <rnabioullin at gmail.com> wrote:
> On 11/10/2016 07:18 AM, Peter Reilley wrote:
>> I have a few of those "atomic" clocks that receive WWVB to set the time.
>> However since I live on the east coast they may only pick up the signal
>> once or twice per year.
>> Could I implement my own personal WWVB transmitter that would
>> be powerful enough to be picked up by the clocks in my house?
>> The signal at 60 KHz might be able to be produced directly by some
>> sound cards.   With that and a ferrite rod antenna I might get
>> reliable time elsewhere in my house outside of my lab.
>> Has anyone tried this?
>> Pete.
> To be honest, this is very impractical and backward-thinking.  I would suggest instead upgrading to the Internet-of-things paradigm, replacing these time-of-day displays with full computers running NTP and connected to your LAN (Android smartwatches; repurposed old smartphones, tablets, laptops, etc.; and smartclocks

Ok, I have one to two dozen clocks around here that sync to WWVB. I swap out batteries every few years and they all keep chunking along. No wires to any of them. No updates or patching on a regular basis. They each have nice useful displays that make sense for their location. The cost for the batch of them was < $400 and that was over a 10 to 20 year span. I have yet to see one of them die. 

If I replace all of them with computers, they all need displays on them. Not small displays, but displays that I can see from across the room. The display on a phone or an old tablet isn’t going to cut it. I will now be running / patching Linux on all those devices so none of them are exactly small machines attached to the displays. I have a number of NTP servers running around so yes, I have a pretty good idea what the hardware will look like. I need to get power and network to each clock location. Unless I really enjoy WiFI nonsense, I’ll hard wire them. I also need to work out how to mount the displays and the computers in each location. 

There is the minor issue of errr … money. If each display is $100 and the Beagle Bone is $50, 24 of them will run me $3600. There will be another ethernet switch in the mix as well. There will be power supplies, mounting boxes and other stuff.  They each will pull at least 50 W with the monitor on. That’s 1.2 KW at 10 cents a KW plus tax plus air conditioning in the summer, call it 20 cents a KWH. That is about $2.1K a year. Over 10 years it’s another $21K. 

So what do I get with my investment?

I get a bunch of displays that aren’t going to last five years of 24/7/365 operation (let alone 10 or 20 years). I get a bunch of night lights in places they are not useful (or wanted). I get a system that is less reliable than what I had. I get to have even more fun patching and debugging everything on a regular basis. I get a bunch of clocks that are ugly compared to what is there now. 

Hmmm ….. why would I do this?


> [I'm certain that some Silicon Valley ``genius'' has already come out with such an ``invention'' and the Chinese are churning out cheap knockoffs]), which will query your home metrology lab's NTP server(s), and instead using WWVB as an additional timing signal for diversifying your timing source portfolio (with a good antenna, of course), if you haven't done so already (though such products appear to be extremely sparse nowadays, for civilian-minded users have superficially reasoned that GPS is all that is necessary).
> -Ruslan
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