Anyone else notice this?

About a week or so ago, before city shut down outside activities, I managed to get out for about an hour and a half to dig deep iffies for testing...
Only dug about 6 or 7 deep holes, but the last one was a really nice 1910 Barber dime at 9".

What I was noticing, was that with all the businesses shut down (for COVID-19) around the park I was hunting, the EMI was almost non-existent!
I could run just about full throttle in a park that has been known to completely shut me down with the surrounding EMI.

Signals were much cleaner / crisper, and easier to judge.
...and, of course, much deeper.

It really emphasized a limiting factor for finding old coins with existing technology (in the areas I hunt) .... getting depth with EMI.
Not separation, or ID, or recovery speed .... depth with bad EMI.

I guess that's one good thing about this current situation.
Now, if I could only sneak back out for more hunting, lol.

Now that you mention it Mike, my f-75 was rather quiet the other day, which is unusual. I hit a quarter size lead disk at 10" deep....that's about an inch deeper than the unit goes on a coin size object around here . . .And it ID'd in high numbers with a high tone,,,thought I had a big copper. I also noticed I can see stars that are lower on the horizon where as pollution use to block them out.

EMI is the #1 inhibitor of depth.


(Then add bad dirt).

I have noticed the same thing. One old school in particular always had bad emi. Hunted it yesterday morning with both the F 75 and A T Pro and both ran quiet. In fact, recovered 2 Mercury dimes, each in the 7" deep range. Not all that deep, but other times trying to hunt that particular area emi would literally shut one down. Stay safe everyone. HH jim tn

So what are the sources that aren't operating now? School wifi? Local radio signals?

What you mentioned Champ, along with A C/Heating units, school computers and in general, simply less power sources not in use and drawing power.....is my assumption. HH jim tn

Airplanes, passenger trains, cars, anything else?

All of the above plus that blasted electric fan Grandma got for her wood stove!!!!!!

It's amazing our metal detectors work at all in an urban environment with all the stuff being emitted around to mess up the signals.

That's a great observation....hmmmm

Champ Ferguson Wrote:
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> So what are the sources that aren't operating now?
> School wifi? Local radio signals?

Not just school wifi .... many retail businesses offer free wifi.
Then everyone actually using the wifi.

Add to that the neon light displays in the front of many restaurants / bars. (Those things are horrible emitters.)
Not to mention the normal fluorescent lights that are now off.
Big sound systems / amps / PA systems.

Electric cookers / mixers / blenders .... appliances of all kinds.
Computers / cash registers.

Then the traffic that's now NOT driving by with their high voltage ignitions driving spark generators.
People not walking by with their cell phone on.

And of course, all that Jim mentioned.

It's impressive how much electricity society uses at any given moment.

NASA-Tom Wrote:
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> EMI is the #1 inhibitor of depth.
>
>
> (Then add bad dirt).

Exactly!

I guess I never thought those signals would extend very far. I mean, heck, I can barely hit my router at the other end of the house!

NASA-Tom Wrote:
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> EMI is the #1 inhibitor of depth.
>
>
> (Then add bad dirt).


Absolutely, without a doubt, period. Mike has a great “a-ha” moment going on there.

Time of day and temperature makes a difference. I laugh when someone finds lots of stuff in a hard hit area thinking it's the detector. When I detected some of the Treasure Coast I realized that on hot days everyone's A/C was on so the EMI was high and sensitivity had to be turned down. When the temperature dropped towards the evening.... EMI went down so detector sensitivity could be turned up.

Many times you can't hear EMI but it's affecting your detector big time. I wrote about this way back in 1999.

Testing a "broken" metal detector on an old farm road near my house turned out to be interference from a microwave....LOL At what frequency is least sensitive to modern day electronics???

Cal_cobra Wrote:
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> That's a great observation....hmmmm


UUhhh, ahem .... ALL THE MORE reason to go detecting now ? Huh ? Huh ?

Tom_in_CA Wrote:
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> Cal_cobra Wrote:
> --------------------------------------------------
> -----
> > That's a great observation....hmmmm
>
>
> UUhhh, ahem .... ALL THE MORE reason to go detecting now ? Huh ? Huh ?

Absolutely, but not where you want to go, there's no EMI there to begin with - lol

GGP would probably be awesome right now

Cal_cobra Wrote:
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....
>
> GGP would probably be awesome right now


Haha, but .... the various places in SF where EMI has "given fits" to the Nox in the past, I'm afraid are still simply too close to people's homes. Such that they're all still simply "sitting in their living rooms" on their electronic devices.

Tom_in_CA Wrote:
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> Cal_cobra Wrote:
> --------------------------------------------------
> -----
> ....
> >
> > GGP would probably be awesome right now
>
>
> Haha, but .... the various places in SF where EMI
> has "given fits" to the Nox in the past, I'm afrai
> d are still simply too close to people's homes.
> Such that they're all still simply "sitting in the
> ir living rooms" on their electronic devices.


I think you'd be surprised. This would actually be a great opportunity to test your median strip, but it doesn't really interest me and you know our wives would have a fit if we told them we were going detecting right now