Does using a lead lined paper bag block emi?

[erte]

i was thinking maybe wrapping a detector housing in a paper lead lined camera film bag would block emi hitting detector housing? do you think it improves detection in emi surroundings? anyone ever try this? they sell these lead paper bags online don't know if it will work?

 

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[beerguy]

Lead is for blocking X-Rays, so it may not have a large effect on your interference. You want to build a Faraday cage for blocking RFI, and it helps to know what frequency is involved.

I am thinking that a mild steel metal box might be a good thing to try as well.


Old Corvettes used to have a cage built around the alternator to keep interference out of the radio.

I used to work at an aircraft maintenance facility, we had an airplane that the autopilot would turn left when you keyed the HF radio.

We fixed it by bonding a big piece of expanded metal over the electronics bay.

It had holes in it that were pretty large, but an HF carrier has a long wave length, so it worked well.

Your lead bag may give you some results, let me know what you try and what happens.

 

[Peyton Manning]

I'm not sure, but aluminum foil protects my brain from radio waves

 

[Ogre1190]

I thought the coil picked up the EMI. Maybe if I wrap mine in lead, it would...oh. 😝

 

[Terry Soloman]

I use a Santeria Priestess to take care of my coil and control box. 100% effective, but the chicken blood is kind of a turn off.

 

[WaterScoop]

The receiver/transmitter is in the coil , the detector housing is only the computer processor that sends and receives EM signals. EMI affects the receiver so if you want to physically block EMIs you would need to block the coil and that would defeat the purpose of the coil 100%.

 

[DizzyDigger]

Spent the latter part of my working career in the field of EMC (Electro-Magnetic
Compatibility), which deals directly with both EMI and RFI. Not an engineer as
I could never do the math, but I do have a very solid working knowledge of
how to shield devices from EMI, RFI and EMP.

Your coil is a transmitting/receiving antenna, designed for maximum efficiency
for the operating frequencies of the detector. It is going to receive not only the
reflecting signals, but also anything else within the operating bandwidth.

Interference can come in the form of near field (magnetic) or far field (electric).

The only way I can think of to shield the receiver would be to install filters on
the cable between the coil and the receiver. The receiver housing would also need
to be shielded internally.

Both of these choices could be detrimental to the function of the detector.

I'd love the chance to get some REAL solutions by sending a few detectors
to a proper EMC Test facility. There, engineers (Physicists) way, way smarter
than us can test the detectors in an RF shielded room, and then suggest
alternatives that would/could solve the problem.

 

[sprailroad]

All good thoughts, but I already solved the problem by moving to another spot. It really works.

 

[against the wind]

I'd love the chance to get some REAL solutions by sending a few detectors
to a proper EMC Test facility. There, engineers (Physicists) way, way smarter
than us can test the detectors in an RF shielded room, and then suggest
alternatives that would/could solve the problem.

Hold on there partner,,
Not smarter than me and Jeff - Gordon,,
Jeff, pass me the foil,,

 

[Peyton Manning]

best thing about foil is one size fits all!

 

[Peyton Manning]

 

[against the wind]

I was thinking if you roll up a little really fine steel wool, (O O O), and stick it in the bottom of your shaft, it will in all likelihood, stop the EMI that you are experiencing.

 

[DizzyDigger]

I was thinking if you roll up a little really fine steel wool, (O O O), and stick it in the bottom of your shaft, it will in all likelihood, stop the EMI that you are experiencing.

How?

There's dozens of spots where EMI can enter the circuitry of a detector.
Starting with the coil, the coil wire (perfect antenna), the coil's connection
to the control box, the box itself, the handle, every screw location could
be a leak. Then, there's the internal circuitry itself, as it can generate it's
own emissions and harmonics.

 

[GA_Boy]

Gentlemen, If there was a solution to this problem I would like to think that the Manufacturers would have solved it years ago.
You all are trying to pick out the fly poop in black pepper and it can't be done.
Marvin

 

[Tommybuckets]

Start by turning off your cell phone when detecting

 

[curious2]

More can always be done by the manufacturer in the design to manage EMI, although there are often tradeoffs--look at the F75's history. In practical terms, it's difficult for the user to do anything beyond what settings the machine provides except try different coils and change locations. You could try draping a metallic mesh tent completely over you and the detector (large enough not to bother the coil), which might help with overhead power lines, but dragging that along probably wouldn't be much fun.