Will The Next Gen Detectors Address Emi ???

[dogodog]

Over the last three to four years we have eagerly awaited new machines that will give us an edge to find the ever so deep or trash hidden targets. We have seen multiple manufactures come out with detectors will all kinds of bells and whistles that are supposed to make our hobby more exciting. I've seen lighter, deeper, MORE power, user friendly, more expensive, Multi frequency and the list goes on and on. As each and every day passes, more and more housing developments and parks are being constructed. With that comes a tremendous amount of new power lines (buried or overhead) and WIFI. There are places that I hunt that EMI was never a factor, But now I'm dealing with it on a regular basis. I'm fairly sure that most of the issues are WIFI related (maybe I'm wrong). For instance I can detect directly under a huge power line with very little interference, While I hunt a particular park with a housing/townhouse development that borders it and my machines will go mental. This one park in particular at 7:00am on a Saturday will be quite peaceful, and be unbearable by 9:30am. I'm guessing that as people wake up they are hitting up their social media accounts and other various computer related stuff which causes all of my suffering. I can not be the only one that is dealing with this problem. So the first question is would you like to see a machine that can deal with/overcome EMI and WIFI??? Second question, Can Manufactures deal with this issue or is it some KHZ related issue that we have to live with thanks to the FCC??? Third question, Is it even on their radar??? This is an issue that most of us bitch about but nothing seems to change or get addressed. SO let me know what your thoughts are, This has been bugging me for quite some time. I hope the Engineers from Minelab, Nokta, Garrett and others are listening, This is something that I would be really interested in!!!!

[Erik Oostra]

4 minutes ago, dogodog said:

I'm fairly sure that most of the issues are WIFI related (maybe I'm wrong). For instance I can detect directly under a huge power line with very little interference, While I hunt a particular park with a housing/townhouse development that borders it and my machines will go mental.

I reckon you're spot on Dogodog with the issue being WIFI related.. Both my Nox and D2 go mental on a beach near a backpacker hostel when their WIFI is on.. There's also a powerline with a box nearby which never causes any interference.. 

[TampaBayBrad]

I hunt with my Manticore within 50 yards or so of condos and hotels on the beach and I haven't had any issues after doing a long press noise cancel. Other reports are saying Manticore was a good jump in handling EMI from earlier models.

I never noticed EMI problems with my other ancient detector, Fisher CZ-21 either though. I know these places I hunt have wifi, maybe I'm just not close enough to the routers for it to interfere.

[dogodog]

Erik, Thanks!!! I had a feeeeeeling this was the Evil that haunts us all. My soil is bad enough, the extra noise is horrible. And I hunt with average sensitivity. Now go make someone's day!!!!😃

[dogodog]

Brad, you are a lucky soul my friend. I hunt the Virginia Beach area and do not have problems when in beach mode. Put it in something else and it's over. I'm a tester, so I try all kinds of programs in different areas to see if it's WIFI related. All of my dirt programs are destroyed by WIFI, oddly beach not so much. Not sure why it happens.

[CPT_GhostLight]

I have a feeling that it's more than just WiFi that is a problem. The airwaves are more congested than a Friday rush hour in LA and getting more congested by the day. As our exploding populations spend more and more of their lives on their wireless devices the demand for bandwidth rises exponentially and Wifi, Cellular, Radio, Microwave and other wireless device manufaturers increasingly battle for more bandwidth usage and this is just the private commercial sector. We live in a soup of man-made EMI transmissions and that soup is thickening to a paste.  So enjoy what usage we can get with the newest detectors while we can. At some point we may have to go back to closed system hard-wired detectors with massive shielding just to find an irradiated zinc penny laying on the surface of the ground in our electro-magnetic shielded hazmat detecting suits. Of course that's just my opinion, I could be wrong. 😏

[TampaBayBrad]

16 minutes ago, dogodog said:

Brad, you are a lucky soul my friend. I hunt the Virginia Beach area and do not have problems when in beach mode. Put it in something else and it's over. I'm a tester, so I try all kinds of programs in different areas to see if it's WIFI related. All of my dirt programs are destroyed by WIFI, oddly beach not so much. Not sure why it happens.

Interesting. I had no idea beach programs were the EMI answer. You must have crossed paths with GraveDiggerMax in that area a few times, huh?

 

[Chase Goldman]

Why wait until next gen?  XP has done a great job at addressing the issue today AFAIAC.  I am able to regularly run the Deus 2 at greater than 90% of max sensitivity with great depth compared to my Nox 800 and 900 that seem to struggle if within visual line of site to known noise sources such as cell/radio towers, transmission lines, Wi-Fi emitters, or even other detectors and pinpointers.  So to answer your questions…

1 hour ago, dogodog said:

So the first question is would you like to see a machine that can deal with/overcome EMI and WIFI???

Yes, I would.  Deus 2 seems to deal with it better than any other SMF machine I have used (Nox 800, Nox 900, Legend, Vanquish) but there are still some “grid-connected” houses that challenge even the D2.  Just to be clear, EMI encompasses all electromagnetic emitters including WiFi which is just a radio operating at 2.5 and 5 GHz (same frequencies as Cell towers though cell towers have elevated transmitting antennas and powers and Bluetooth audio that transmit at very low powers.  Cell phones are somewhere between WiFi routers and cell towers in terms of transmit power and all IT gear, Alexa’s, TVs, Webcams, GoPros, Printers, and even watches have WiFi and/or BT). Then you have high power transmission lines and transformers, other radio frequency emitters (radar, aircraft, terrestrial radio and HDTV transmitters, and satellite commas), electric cattle and dog fences, fluorescent lights, LED power converters, cracked insulation in power boxes, internal combustion engines with alternators and rotating generators, electric vehicles (including e-bikes!) with static electronic motor drives, and even transient natural emitters such as lightning, cosmic rays, and solar flares.

1 hour ago, dogodog said:

Second question, Can Manufactures deal with this issue or is it some KHZ related issue that we have to live with thanks to the FCC???

Manufacturers can deal with this issue by providing sufficient shielding but the issue is complex.  How is the EMI manifesting itself?  What type and how is it getting into the detector (i.e., via the coil or via the control box)?  (A myriad of different problems with different mitigations/solutions).  The mitigations are generally limited by manufacturing cost (providing sufficient shielding) and environmental variables vice technical capability.  If a manufacturer is relying solely on an operating frequency shift as a band-aid mitigation, that is woefully inadequate.  Furthermore, the issue is exacerbated by the fact that these are sensitive instruments working at sensing micro watts  and in a world that is spewing EMI from megawatt sources in many cases.  That’s a 1x 10^12 range (a 1 with 12 zeros after it).  Not to mention that the detector’s microprocessor electronics self generates EMI that has to be dealt with just like it has to deal with your nearby phone, GMRS radio or GoPro.  And if it is a simultaneous multifrequency detector, you must let in a wider bandwidth of 

The FCC and similar international governing organizations actually try to combat the issue by limiting consumer and industrial users to stringent EMI emissions limits.  If manufacturers actually follow those refs and guidelines (beyond just the certification testing) then EMI is greatly mitigated.  I suspect the issue is that a lot of shady stuff goes on and bypasses the regulatory certifications resulting in a lot of spurious EMI that is hard to mitigate.

1 hour ago, dogodog said:

Third question, Is it even on their radar???

It is, but at some point the cure can also mitigate detector performance somewhat, and then there is the R&D investment (huge testing time and cost sink) and the recurring manufacturing cost of implenting physical shielding mitigations.  At some point, for a non-safety critical consumer device, it may just not be worth the trip to go above and beyond FCC or CE certification requirements as far as the manufacturers are concerned.

So, how do you work with what the manufacturers give you?  Here's my approach with a simultaneous multifrequency machine.  My basic philosophy is not maximize depth to the extent practical, but to take the depth you get by maximizing signal to noise ratio to the extent practical.  

1) If you can avoid EMI laden sites, do so or at least stay as far away as possible from the visible sources of noise such as cell towers or other antennas, transmission lines, electric fences, transformers, motors (e.g., a well or water pump house), or "grid-connected" structures that may have power and wifi.

2) Run the manufacturer's noise cancel routine, which is just a quiet channel frequency scan.  If you have near field sources of EMI (cell phone, pinpointer, another detectorist) have them nearby and energized when you run the noise cancel.  I honestly do not think the manual sensitivity setting should have any bearing on how a frequency scan is accomplished but the manufacturers are not entirely clear on this aspect, either.

3) Make sure you understand the difference between EMI and ground noise.  Ground noise will only manifest if the coil is moving.  If all is quiet with the coil not moving but things get unstable when you swing, then the issue is ground noise not EMI.  Do a ground balance, cancel out the ground signal with disc or notch, or lower transmit power as necessary.

4) Avoid running at max sensitivity unless you can but reduce sensitivity if you are still getting interference on the "quiet" channel.  If that is the case, and you are concerned that you have to lower sensitivity too much, then change modes to a different simultaneous multifrequency profile (avoid high sensitivity modes, if possible, such as high frequency micro gold modes, as they are more susceptible to both EMI and Ground Noise).  You may have to re-run the noise cancel (quiet frequency channel) routine as that is typically mode specific.  Trial Run SMF modes you would not consider ideal for your environment such as beach modes at a farm site, etc.  You never know when some experimentation might reveal a non-obvious solution to the issue and enable to utilize the advantages of SMF.

5) If no simultaneous multifrequency channel achieves an acceptable combination of quiet and sensitivity, then try going to single frequency.  Typically middle of the road frequencies do best (8 to 15 khz) against both EMI and ground effects.  But again, experimentation is key.

6) Re-run the noise cancel routine as needed.  Especially if you get closer to those noise generating sources at the site or if you and your buddy's detectors are interfering with each other.  That often cleans the problem right up.

HTH

[Digalicious]

On both my Vanquish 540 and my Legend, noise cancel does basically nothing. I've also watched countless detecting videos, and it didn't matter if they were using the 540, 800, Legend, or D2, because not once in any of those videos did the noise cancel do anything either.

I then posted the above on another forum, and asked anyone to post a video of themselves, or any other You Tuber, in which the noise cancel quieted down the EMI noise. As far as the replies go, many agreed that noise cancel did nothing for them as well, but no one produced a video that showed noise cancel actually doing anything. I posted the same thing on a Minelab and Nokta Facebook Page, and again, no one was able to produce a video, or provide a link to a video that showed noise cancel doing anything.

There is something inherent with SMF,  that for lack of a better term, "amplifies" EMI noise. This of course is why when SMF is very noisy in EMI, any SF mode will always be quieter. I asked an engineer why that is, and he explained that when the SMF signals are combined and added together, then so is the EMI. 

To mitigate EMI, a smaller coil may be used, or reduce the sensitivity, or switch to a SF.

In regards to Dogodog's question, I honestly don't think manufacturers can do anything about it via software. I'll write a separate reply explaining my reasoning behind that.

[dogodog]

42 minutes ago, Chase Goldman said:

1) If you can avoid EMI laden sites, do so or at least stay as far away as possible from the visible sources of noise such as cell towers or other antennas, transmission lines, electric fences, transformers, motors (e.g., a well or water pump house), or "grid-connected" structures that may have power and wifi.

Thanks for the info Chase, Some of my sites are so good, that's just not possible. Electrical interference just does not seem to be the problem. Would you walk away from sites that have a bunch of silver and colonial coins?

 

45 minutes ago, Chase Goldman said:

If no simultaneous multifrequency channel achieves an acceptable combination of quiet and sensitivity, then try going to single frequency.  Typically middle of the road frequencies do best (8 to 15 khz) against both EMI and ground effects.  But again, experimentation is key.

The only time I run multi is with the 800 and the 6'' coil. 99% of the time I run single Frequency, High EMI areas I'm forced to run 40KHZ. Anything from 4khz to 20khz is bad. I pretty much hunt early in the morning to avoid the worst of it. Sadly I've become fairly good at hunting in the worst of the chatter. But there are days where I just give up. 

 

56 minutes ago, Chase Goldman said:

3) Make sure you understand the difference between EMI and ground noise. 

Ground noise I welcome, and its very similar to Culpepper ground. Both combined are not fun. I would gladly pay more for a machine that can handle the interference. I think at some point most mfg's will have to address it.