[time-nuts] webcam app to watch for and time stamp changes

Jim Lux jimlux at earthlink.net
Sun Mar 3 13:44:54 EST 2013

On 3/3/13 10:09 AM, Poul-Henning Kamp wrote:
> Content-Type: text/plain; charset=ISO-8859-1
> --------
> In message <51336234.3090105 at earthlink.net>, Jim Lux writes:
>>> Most LCD and LED clocks have a shielding metal-coating on the front
>>> glass, exactly to eliminate all EMI/EMC issues.
>> Yes, but perhaps there's enough leakage to make this work.
> Think for a moment about how little power the electronics consume
> in the first place, then do the math.
> You'll need a very (radio-)quiet place to measure in...

Not so oddly, I happen to have such places available, since we develop 
sensitive radio receivers and instruments for deep space.  I don't know 
how well shielded from a magnetic field standpoint our usual screen 
rooms are (probably not very.. they're all designed for 2GHz and up), 
but it's easy to try.

I also know someone who has a set of nested mu metal cans for this kind 
of thing that I might be able to borrow.

We used them to calibrate little hockey puck shaped spinning 
magnetometer subsatellites for a sounding rocket experiment:


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