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

Magnus Danielson magnus at rubidium.dyndns.org
Sun Mar 3 12:51:31 EST 2013

On 03/03/2013 06:18 PM, Chris Albertson wrote:
> On Sun, Mar 3, 2013 at 12:10 AM, Tom Van Baak<tvb at leapsecond.com>  wrote:
>> Do you have suggestions on what sort of "antenna" to use to pick up the LCD AC E-field? I'd expect the LCD drive current to be vanishing small.
> Many turns of fine magnet wire going all the way around the device.

As a E-field antenna that's not that good, as you need to see both 
polarities. Tossing a wire around like that would sense a little too 
much of both, so it will cancel out.

A typical E-field antenna is a coax cable, stripped of wire, possibly 
with a ball attached to increase the area.

H-field can make use of one or more loops before reaching the ground.

The near-field H-probe is two loops, wired such that long-distanced 
fields cancels, but high-gradient fields is picked up. You should be 
able to do the same for E-field, essentially three fields, with the 
outer two being hooked to ground and the middle one to amp.


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