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A couple Verizon techs knocked on my door today with a bunch of equipment.

Turns our my mid-sized mining setup (11 cards) is causing interference with a cell phone tower that's 800ft away. So much so that they've spent quite a while tracking down the source.

They checked each rig separately (all mostly running R9 280x's from a variety of manufacturers) and found that each one was emitting the same amount of interference, ruling out any potential individual component that was causing the problem. They asked me to turn them all off until I can find a way to shield them from causing interference. They offered to come back and test again after I move things around and find a way to block the interference. I'm hoping that a makeshift faraday cage with some chicken wire will do the trick.

If you're located near a cell tower and currently mining or plan to, be warned: You might get paid a visit by your local cell phone carrier and have to turn it all off  :(

What can they do if you refuse to do so?

They hinted that it may be against the law and that there could be penalties if I turned them back on. I didn't argue with them too much about it. But I'm interested in hearing if the community here has any thoughts on it.

Tell them you'll gladly turn them off if they compensate you monthly for your mining profitability + a percentage.

Otherwise tell them to piss off and get off your property!


It may be a crime to "maliciously" interfere with the tower but you could easily circumvent that.

Isn't the whole point of a FCC approval to make sure that communications equipment doesn't cause interference in neighboring systems, and to be as resilient as possible to nearby residual interference? If that's the case, then I'd say that they did a lousy job with whatever equipment is in that Verizon tower: Probably a CMDA or LTE antenna?

And 800ft seems kinda far. I mean BT and Wifi only have a range of a few hundred feet, and when you're talking almost 1,000 ft, that seems kinda far.

What kind of laws are you breaking by running NON-COMMUNICATIONS equipment that happens to be nearby to a cell tower? I mean my Gigabyte 280x all have a FCC approved label on them, and I'd assume all GPUs would. I don't see how they could fine you for running FCC approved, non-communications computer hardware in your own home. I'm no lawyer, but I'd keep running them regardless of what some technician tells me, and if they really do have a law or regulation somewhere that tells me I can't, then I'd consider stopping.

So in the end, I say it's bullshit, but what does my opinion matter? If you really want to keep them up, I'd say you gotta ask a few questions:
1) What kind of cell tower is nearby? What frequencies?
2) What kind of interference is being emitted? What specific frequencies?
3) What laws or regulations are there that say you can't run your hardware?
4) Are these laws or regulations enforced? What fines/consequences are there?

That's just to start. I'm sure I'll have more questions once you get those 4 answered.

if you're in the states, computers fall under 47 US code part 15 subpart b:  "unintentional radiators" (lawl)

http://www.law.cornell.edu/cfr/text/47/part-15/subpart-B

this is why electronics are certified with a faraday cage (i.e. metal case) to contain the electronics which may cause interference.  

if the videocard is freeballin' outside a case, it probably does cause all sorts of short-range radio noise because no mfg. i know spends money to shield each individual component.  

Just read an article today on Wall Street Journal about FCC folks visiting people and asking them to turn off fluorescent lights, electrified fence and other equipment.  Even certified equipment can produce interference, and it is against federal law to squatter on frequency ranges.  So you can tell Verizon techs to piss off, but when FCC comes-a-knocking, you better comply or risk federally enforced fine and as far as I remember even imprisonment.

BTW, article says once FCC forced some dude to turn off some simple piece of electronics (like alarm clock) because his neighbor amateur radio operator complained.

"FCC Agents Trace Radio Interference to Doorbells, Videogames, Blankets"
http://online.wsj.com/news/articles/SB10001424052702304434104579378994224188328?KEYWORDS=fcc&mg=reno64-wsj&url=http%3A%2F%2Fonline.wsj.com%2Farticle%2FSB10001424052702304434104579378994224188328.html%3FKEYWORDS%3Dfcc

How is this even possible?

I would tell them to send the law. I doubt the FCC is going to take on one dude in one neighbor for one cell tower. Also I would tell them that it is compute equipment that you are not doing anything illegal with.

lol, spooky how they tracked u down

800ft does seem relatively far for me too, but one of the four antennas on the tower is pointed directly at us with line of sight so that may be a factor.

I don't know much about FCC approval. My theory is that the cards weren't intended to be used in this way, and maybe they would have failed FCC tests if they were. Just speculation on my part though. They suggested that I contact the manufacturer and complain, but I doubt that would get me anywhere.

As for leaving the rigs running, it's not worth the few $ a day to risk the FCC knocking at my door next. The technicians seemed relieved that they finally found the source of what seems to have been a big issue for them, so I didn't want to be a jerk and refuse to turn it off.

They said the interference was around the 835mhz range. Wikipedia indicates that Verizon and ATT run their voice service at 850mhz, so I guess that's pretty close.

800' seems far for BT and WiFi IFF it is operating within FCC limits  ;D  if you install open firmware on your router you can boost the signal strength to the limit of your hardware. 

did they mention what their measured signal strength from your interference was from the antenna?

this may look ridiculous, but you can get 100db of noise reduction by literally wallpapering your mining room with kitchen tinfoil.  

http://www.thesurvivalistblog.net/build-your-own-faraday-cage-heres-how/

make sure you save some for hatmaking.

For starters, why the hell did you admit anything to strangers knocking on your door?
Unless they have:
A) A gun with a corresponding badge with arresting authority
B) A Search Warrant
Tell them to piss off.

Now that the cat is out of the bag, turn your rigs back on. If they come back tell them they are still off since the last time they visited. If they question you, tell them to kindly leave your property. If they insist on staying or want to gain access, call the police immediately.

By the time the FCC convinces a Federal Judge to obtain a search warrant (a long time), the scrypt diff will be so high you probably switched to ASICS by then, lol.  :D

You do have rights you know.

Yeah, that would be my thought.  Running without a case probably voids the FCC compliance.  There may or may not actually be a law, but the "F" in FCC means that won't stop them.

There is no law on what sort of case you need to use. You don't legally need a case. The cards are tested alone for interference.
I have miners in 1/2 case, no case and even a lexan full case! Am I not allowed to use lexan?  :D

I've seen Dell cases that could probably withstand a friggin EMP pulse and I've seen cases made out of wood. All "legal".

the FCC doesn't give a shit what your case is made of, or if you have no case.  they only care if you are generating interference.

No federal law prohibits lexan cases, if its components do generate interference, the case must contain a faraday cage/EMI shielding to control interference if your hardware happens to emit radiointerference on the frequencies they care about.  

e.g. https://i.imgur.com/M29CWQp.png

if you are selling computers, you technically need to comply with FCC guidelines.  that's why prebuilt computers, radios, printers, monitors, and even mobile phones have FCC certification logos on them.   there are different regulations covering assembled computers for sale. 

a wooden case can be made with EMI shielding on the inside; it's extremely simple to be compliant as mentioned above, some times it can be a sheet or two of metallic foil.  an anti-static bag is also a faraday cage.  

it's not that hard to meet FCC regulations.  frequently it's the knockoff crap (e.g. imitation or imported phone chargers, counterfeit light ballasts, grey market goods) that have fake logos or certifications that are causing the problem.

it's not only in US either: butterflylabs had asics siezed by germany for faking european CE certifications

http://buttcoin.org/butterfly-labs-caught-allegedly-faking-ce-certification-bitcoiner-gets-his-miner-seized-in-germany

this is correct.  (i'm not a lawyer)

verizon technicians don't have any authority over you and you can tell them to go away.

however, OP will probably get a letter from verizon.  then verizon will make a report to the FCC.  then the FCC will write OP another letter, and may come visit OP.

this is what you should do if the FCC visits:  these are your rights.

http://www.roguecom.com/rogueradio/fccknocks.html

OTOH, If the op gets rid of the interference himself, there is no complaint and all of this hassle goes away.  verizon is not asking anything unreasonable; they don't give a shit about your mining operation if it doesn't affect their phone operation.  

it's far simpler to do some research, and shield your mining operation with a faraday cage than to have a showdown in federal court.  

Are we talking about potential health issues with mining rigs?

There actually was someone in the Netherlands that had about the same happen to him. It was a thread in the Dutch subforum:

https://bitcointalk.org/index.php?topic=488572.0

Two things:

1) If your rigs are emitting enough RF "noise", then it wouldn't be that hard for VZ techs to find the source.

2) 835 MHz != 850 MHz.  I know the numbers look like they are "close" but not when it comes to RF.  Look at how many channels we have for Wifi (http://en.wikipedia.org/wiki/List_of_WLAN_channels). The non-overlapping ones are 25 MHz apart (same as 835 to 850).  You can have two wifi networks running right next to each other, one on channel 1 and one channel 6, and have them work perfectly.

I too call BS.

It doesn't hurt to keep the rigs running and see if they will come back again. I would see how about getting compensated for any losses if they pressure you again.

I wouldn't have turned them off.

This sounds like the right course of action to me.  Good for you.

1. most likely the fcc approval was achieved with the cards inside of a metal PC case?

2. if not I would be surprised if they can force you to turn that off

3. funny how you (and others as well) have to bear their electrosmog 24x7, while they do not accept yours, which is probably much weaker

Go for the chicken wire ...  good for mining chikun anyways :D

The noise might not only be generated at 835MHz, it probably has a peak at 835MHz with a rolloff to adjacent frequencies.

Even if it does only emit at 835MHz, the band-pass filters for the equipment that communicates with those voice frequencies are only made to block out unwanted frequencies up to a certain amplitude. You can, for example, generate a white-noise machine that makes all FM radios in the area useless by using a 100MHz oscillator with an amplifier, simply because the filters used on the radios aren't designed to anticipate a white noise source right in the middle of the frequency range that is so much stronger than the signals from radio stations.

Your wifi network example only works because the equipment was designed with that use case in mind, plus each frequency range has a buffer zone to avoid significant pollution into the adjacent ranges.

So no, it is not BS.


Seriously, just deal with it. Block the EM noise yourself if you want. Now that you are on their radar, if you don't fix the problem by either using adequate shielding or turning it off, you will eventually get the FCC involved along with a court order.

This isn't even something worth fighting on principle. These laws exist for a reason. If there wasn't strict regulation of EM interference we wouldn't be able to use all of the modern wireless technologies today without a lot more problems. The little boys telling you to ignore this are just being childish jackasses who aren't knowledgeable enough to have a valid opinion.

There would never be any compensation, nor should there be. If their equipment is designed and operated according to FCC guidelines, they aren't in the wrong.

+100... you don't have to let anyone in your house, even if they are police or some law enforcement agency. Never admit anyone.

If they have a warrant or probable cause that you are committing a crime, they don't need to ask your permission. So if they ask, you say no.

How about a spread spectrum setting in the bios ?

Great.

Mining Rig and Spoofing All in One.

I'd like to reach out to the OP here.  I'm in a unique position here to possibly help get some clarity on this situation.  I'm an alt coin miner and I just happen to also be a Verizon Wireless technician that works on cell towers as well.  I've had to hunt down my fair share of interference over the years & I'd like to be able to reach out to my co-workers that you spoke with to find out the symptoms of the issue they were working on.

plot twist: They weren't really with Verizon, you now have malware on your computers

I recently received a similar visit and wouldn't let the tech in my place.  He was looking for the source of interference to a nearby cell tower.  I have 16 r9 280x mining ethereum across three rigs.  Not sure how I'm going to proceed. 

If it were me personally I'd just keep them running until something comes of it. Tell them if they want it off they can reimburse you for the lost profits. You're probably making bank off those rigs.

Can keeping a GPU rig close to a wifi router cause interference? I noticed that when I am in the other room, the speed are kind of wonky.

However its an old Macbook Pro which always had wifi issues.

Didn't read all the posts so excuse me if this has been said.

Get the official report from Verizon and forward it to AMD and tell them you want new cards that
don't emit EMI. Don't forget to mention that your GPUs are a source of revenue which you are no
longer making.

there is a tv station tower near my location, maybe ~150 meters away..i don't know if it interferes, good luck to them finding my rigs.  ;D

Well all our boards passed FCC inspection before they can be sold, so we aren't in the wrong either.

As the guys said early, these cards do not interfere when they are in a metal cage. I do not have cell tower near me.

Skims the thread....


0) A WAG. PCIe bus extension cables maybe acting as broadcast antennae.

1) You could have all kinds of legal liability, it's stupid to hassle these cell phone guys.

2) Get technical with the techs. Ask them:

a) What frequency is the alleged interference at?

b) What is the legal maximum rf field  and how much are you exceeding it? They need to give you exact numbers.

c) What is the measured rf spectral distribution?

d) What is the rf noise floor of their instrument?

e) Have these guys checked their cell tower ground?

3) If you have any ham radio friends or acquaintances talk to them about this.

4) Some suggestions. (Home Depot or Loews or tractor supply  is your friend.)

It's important to know the frequency because you want to know the wavelength.

a) To attenuate RF you use metal shielding. 800Mhz has a wavelength of 37.5 cm. 900Mhz is 33.3cm.

b) IMHO you could shield your (bare?) rigs by using wire fence material, specifically chicken wire fencing as long as the wire spacing is shorter than the wavelength. Chicken wire will also not obstruct any air cooling. You could shield a group of rigs just as long as the rigs are enclosed and the wire fencing is not shorting anything. The chicken wire shielding must be grounded. You could make some sort of cage like structure attached to a good ground using an alligator clip for easy component access. Just as long as you surround one or more rigs with chicken wire you should be ok. You can use the cheapest stuff as long as it's all metal and not some nylon stuff.

5) RF noise on the power line. You could have a bad facility electrical power line ground. Sometimes contractors omit the ground wire or just use a water/gas line for the panel ground. For the anal types, buy a copper coated grounding rod with the appropriate clamp hardware + wire  from L's or HD, install and run a new ground to your rigs. This would be the electrical code way of doing it.

6) I would also think about putting a plugin power line filter on the AC supply line.

It's the risers most likely. Switch to USB risers they are shielded

Same here. I would have said them to go fuck themselves, because I wasn't listening to Verizon. When you buy a product, it has some warranties that it doesn't cerate some junk.

Would be a dick move. Clearly the rigs are causing interference. FCC certs simply mean that when you use your graphic card as intended by the manufacturer, i.e. sitting in a 'puter case, displaying vidya, your  won't cause RF interference. It does not mean that your graphic card won't cause RF interference if, instead of using your graphic card as a graphic card, you h4xx0r the firmware and run a boatload of graphic cards propped up on a rat's nest of antennae risers to mine crapcoins.
Your microwave oven is also FCC certified. Please don't misconstrue this as a license to defeat the idiot switches & run the thing with the door open & complain that it interferes with your WiFi. It wasn't designed for that.
Why is this difficult to  grasp?

Well, you're right, but what would happen if I would be countinuing to use it ? I would at least ask them to pay me back the price of the cases.

Probably nothing. Just like nothing would happen to you if, instead of throwing your trash in a garbage can, you threw it in the street. But it would make your city a shittier place to live in, and there is a chance you'd get a ticket for littering. If enough people behaved like you, cops would be told to start enforcing the littering laws more diligently (read: be dicks).

Same with shitting up the RF spectrum -- you can get away with it 9 times out of 10, tho it makes life worse for everybody. After you have been warned to cut it out, you could get heavy fines & your gear could be confiscated (though that's pretty unlikely). If enough people act like you, the FCC might create more/stricter regulations, making all electronics more expensive.
Here's a link: http://www.arrl.org/part-15-radio-frequency-devices (ctrl-F "Digital device:§ 15.3 (k)")
TL:DR: Don't keep doing bad things just because you can get away with it.

But you're the one breaking the law (see link). Asking the Verizon guys to pay you to stop breaking it is ...idunno. Those Verizon techs are just working stiffs, they're not your enemies. If you don't let them in your house (you don't have to), they simply check a box in some form & then d00ds who you *do* have to let in show up, and the whole thing escalates :(