magnetic shield for GPX's

Has anyone tried these and do they work ?

and what are they made of ? sounds like silicon steel.

http://www.ebay.com.au/itm/MAGNETIC...rg=20140122130056&rk=3&rkt=24&sd=251764467876

I think wearing a tin foil hat may help just as much. I dunno.

i find an Armadillo hat works

I think this is a bit of a scam. Any developer of a model looks at shielding and if another level of shielding on top of the existing one seems to be a overkill.
Jaros

Im dont know much about electronics but wouldn't a Faraday cage around the control box grounded via cable to the bottom of your boot be better?

I like the way the eBay advert quotes some happy users but when you look at the seller's feedback, there's also a negative one that says, "Dose not work it rusts on inside staining your control box"!!! :lol:

Cant see any reason why this would work

Silicon steel does have a different effect on magnetic fields than normal steel but i would have been looking at bronze mesh like the radiation protection covers used on mobile phones years ago if twas mee.

We all know metal detectors work on the principle of transmitting a magnetic field and analyzing a return signal from the target and environment.

The magnetic transmitter is in the form of a transmit coil, the receiver is in the form of a receive coil (Both are contained within the one coil in your typical Mono). The coils have a varying electric current flowing through them produced by transmit electronics (The control box).

Basically, this electrical current in the transmit coil causes a transmitted magnetic field which in turn, causes electrical currents to flow in metal targets (called eddy currents).
The receiver in your mono coil detects these magnetic fields generated by eddy currents as a very small voltage, this voltage is then processed by the control box which translates it as an audio beep.

Im not convinced that simply covering the control box (which is simply a processor), will alter any amount EMI being picked up by the coil?
It may help slightly, but i doubt it seeing the coil is being left out of this equation.

Just MHO!

Cheers

EMI/EMC on electronic equipment is generally shielded by a totally enclosed box. Airgaps will allow EMI/EMC in or out, the bigger the gap, the more gets in or out.

Logic would tell me that the control box electronics even if totally enclosed in another container, will still be affected if EMI is present, because of the bloody big magic wand sticking out of the end with a coil at the end acting like an antenna.

Notwithstanding the box is already self enclosed, so definitely a SCAM in my opinion.

Also, have a look at some of your devices, including your detector, most are tested to standards such as AS/NZS 2772, it's usually the cheap knockoffs that aren't.

I didnt yet label it ineffective or a scam

Aluminium is not the greatest shield against EMI

The components in the box could be affected by EMI so shielding it ( with whatever is found to work ) would produce a quieter and clearer signal at the headphones.

jury is out for me until i have more information.

Disconnect the coil from the detector and have a listen to the detector....you'll find with the coil attached, the detector runs quieter.

Foe those of you who have not done this...be advised to leave the detector off before making any connection or disconnections from the control box.

Your waving a transmitter that produces a magnetic field, through another magnetic field, you can expect some problems with that when its a highly sensitive listening device..

I have seen a test done on a 5000 with one of these on it, you can place a magnet on the side of the detector and there was hardly any interference ,placing the same magnet on my 4500 and another 5000 the magnet effected both detector
This was before they appeared for sale on ebay it was late last year or early this year, the person was serious about any type of interference all this coil cables were tunned to a certain length with a electronic meter. All metal on his clothing was removed and boots .
From the test I did see they do help in some way we are using one at the moment on the 5000 regards john

Not to hijack this thread but seeing as this product is inline with the interference filters which can also be bought on ebay for $180 to supposedly filter out EMI from over the horizon radar stations I'll chime in on my experience with this product. When the interference filter is connected your detector will make a blanking sound when you attempt to auto tune and once the process is complete it's as susceptible to EMI as ever except you now have no iron rejection at all if running a DD coil. This interference filter may work for over the horizon radar stations up north but beware if you expect them to do anything at all for any other source of of EMI as in my experience they do zilch..

I have to disagree with that one mate. I run a filter dd specific for a 18" dd with my sd2000. I tested am area 5 min from my house when I got it. I was able to ping a bullet at 45 cm which was quite clear throught the warbling. Without the filter allvyou woukd hear is warble. Ive since bought woodys booster and handfree kit and with tge fikter have been able to detect near places previously I could not. Just my two cents.

Remember when buying a filter dd and mono filters are not cross compatible.

Golddigg, I bought a DD filter on ebay. Perhaps there's a possibility they mistakenly sent the mono filter by accident hence why it doesn't work? Might have to try it with my mono coil and see if there's a difference and report back. Glad yours actually does something

True .. thats actually very likely you know why?? I ordered a mono and got a dd then went and bought the dd after finding out it did squat with the mono maybe you got mine and I got yours lol

the minelab box is a Faraday cage by itself however it will pass magnetic fields so perhaps it works to some degree would some lead shield be a cheaper thing to try first , I doubt there is much magnetic fields out in the bush but i have no way to measure if there is or not

HeadsUp said:

Has anyone tried these and do they work ?

and what are they made of ? sounds like silicon steel.

http://www.ebay.com.au/itm/MAGNETIC...rg=20140122130056&rk=3&rkt=24&sd=251764467876

Click to expand...

File it next to Peter Brock's energy polariser

Hi all

My husband has one bought it 6 months back, now I'm not that switched on but the one thing I know for sure before he put it on his 5000 would go crazy if we were a bit to close so would my 4800.

Now my 4800 which does not have one goes crazy, I stand to look how far away he is when I sight him his head is down he doesn't seem to pick up my 4800.
It makes me mad I often have to radio him to get going the opposite way as he is interfering with me.

He always replays I'm not picking you up. This now happens every-time we go out, Yes we are aware that we have to detect a far way apart I head one way and he the other, its just after a couple of hours in we drift to close.

This is one thing I have noticed about the cover. He will not take it off for that reason.

In saying that I haven't bought one myself yet. I do believe we may be able to detect a bit closer together if I did.

I know its an old post being brought up again but it is interesting to see the opinions of others.

K-M