Re: [Ee] Field mill

Could you use a microcontroller to send the data over a mesh or other 
radio signal to a digital decoder. I use MQTT over both mesh and WiFi. 
(In the past I have also used NRF24L01+ radios.)Single element data 
makes for a very small packet and sending over very short intervals can 
give almost real time visibility. Here is an example:
https://meshgauges.mulvey.us/

Allen Mulvey

On 6/6/2025 11:02 PM, David VanHorn wrote:
> Not worried in the slightest about fields around the output line. If I were
> to use copper cable it would be shielded, and the output voltage is only
> +/-15V so the field that the detector sees would be uV/m at best.
>
> Imagine lightning striking the field mill, and I have a copper connection
> back to my car.....  Conversely a strike on my car, if I am holding a cable
> that extends out from the car could also be fatal.
> Even the leader discharge (just before lightning strikes, and there are
> usually many leaders before a strike, only one usually makes contact) could
> be fatal if I were holding or even nearby a cable connecting back to the
> mill.
>
> Fiber optic could work, but that seems expensive, and would of course
> require some sort of encoder/decoder system.
>
> A normal panel meter is going to be very hard to read at a distance, see
> above for concerns about lightning strikes on the mill.  That's why I'm
> thinking LED bargraph. Highly visible, and no cable to put me at risk.
>
> Lightning photography is a dangerous hobby. I've got significant experience
> and training in severe weather observation under a PhD Meteorologist.
>
> The field mill will indicate about 200V/m on a nice day, then when charged
> clouds are near the field will increase substantially. (2000..5000V/m
> typically, could be higher)  A strike will collapse the field for a few
> seconds, while it builds up again.
>
> Prior to this acquisition, my only available data was "Do I see leaders
> forming nearby?" (EASY to miss) and "Are the antennas on my car glowing?"
> (in which case I should already be somewhere else!!) and I've had that
> happen.
> I'm prepared to abandon the gear if necessary, but I'd REALLY rather not.
>
>
> I have no idea where to find one, but a LARGE analog meter, center zero, of
> 10 to 100uA could work. It would have to be illuminated.  I know they used
> to make such for classroom use, but probably hen's toothbrushes today.
> Visible at 50' or more, in the dark, is the key.
>
> When they launch rockets to trigger lightning, they are sitting in a
> grounded faraday cage building, all the electricals are at the pad, and the
> "cable" is an air hose using pressure to close the remote switch.
> I am NOT trying to do this in the link below, rather I am trying to enhance
> my safety in the field by knowing when strikes are likely to occur near me.
> https://www.youtube.com/watch?v=9wlU6Typ9Y4  There was a much better video
> on the weather channel, but apparently they've retired it.
> A field mill is used in these systems to determine the optimum launch time.
>
>
>
> On Fri, Jun 6, 2025 at 7:17 PM Jason White <
> [email protected]> wrote:
>
>> Shielded differential pair? Coax with ground on outer and signal on inner?
>> Fiber Optic?
>>
>> Why are you worried about the output line generating a field if you are
>> already running power to it? Do your power connections need to be shielded?
>>
>> It seems like it would be straightforward to use a shielded cable and read
>> it with a handheld meter with a backlight.
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