WiFi (2.5 & 5 ghz) disappears randomly.

[p3ter]

Hi,

I have a problem at our cabin where WiFi signals (both 2.5 & 5 ghz) suddenly drop completely and randomly, (can't even see the SSIDs) for a period of time. Usually the wifi is gone for 30 seconds to a minute. Its hard to find a pattern as to WHEN it happens. (I don't see level of usage, time of day, etc as a factor)

• I'm currently using an Asus RT-AC87U, but the issue has been the same with a number of routers.
• When the signal drops, wired connections are still working fine.
• When the signal is present, there are no issues - the signal level is not brilliant (about 3 of 5 bars) but seems either consistent or "gone"
• This house is in the middle of nowhere, with no competing Wifi channels - a site survey shows no other WiFi networks in the vicinity.
• I have turned off DECT phones, and as many 'standby' devices as possible, but the problem remains.

I am experimenting with router placement, but so far seem to be getting the same results. The suspicions I have are:

1. The (99 year old house) wiring has no earth. (although RCD's are installed) - I wonder if electrical noise from the refrigerator could be to blame? - might that make sense with the periods and random frequency? But would you expect electrical noise to cover such a wide frequency as to knock out both 2.5 & 5ghz?
2. The house is very close to some high voltage 10kv electrical lines - could they be in any way involved?

Since I am not at the house so often, it's hard to do longer term process of elimination - can you suggest any tests I can do to find the source of the drop outs?

Thanks!

 

[ColinTaylor]

Look in the router's syslog for any messages around the time of the problem. If the wireless subsystem is restarting itself for some reason you will see it in the logs.

 

[degrub]

any motor starter will broadcast white noise during the closing of the power contact. That means all frequencies. If you have a tv antenna, you may pick it up there and see it on the screen as a noise burst. Refrigerators, washers, dryers, anything with a motor. The noise will be radiated and will be pushed onto the power system.

30 seconds is way too long for that though. The AP device would be expected to accept all interference so radiation should not be the issue. Sounds more like a process restarting in the router, particularly if all models have the same issue. i would put a power isolator (ferrite core transformer, not one of the UPS things) if you can get your hands on one. Otherwise, put a surge arrest/filter device on the power to the router.

a floating ground level will play havoc with computer equipment if it gets above the limit (+ or -) of the diodes providing isolation.

Are the house plugs 3 wire (H,N,GND) or 2 wire (H,N) or is everything 240 V (H,H,N)

what is the rough direct air distance to the 10 kV AC lines ?
That should be a constant electric field strength, not particularly variable.

What is a RCD device ?

 

[p3ter]

Look in the router's syslog for any messages around the time of the problem. If the wireless subsystem is restarting itself for some reason you will see it in the logs.

Thanks Colin - right in the middle of the kids netflix film we get this:

Jun 8 21:25:47 rc_service: httpd 264:notify_rc restart_wireless
Jun 8 21:25:51 kernel: wl_module_init: passivemode set to 0x0
Jun 8 21:25:51 kernel: wl_module_init: igs set to 0x0
Jun 8 21:25:51 kernel: wl_module_init: txworkq set to 0x1
Jun 8 21:25:51 kernel: eth1: Broadcom BCM4360 802.11 Wireless Controller 6.37.14.126 (r561982)

...Nothing in the 7 hours preceding that, and nothing afterwards until I unplugged the router to move it.

looking at the wireless log right now, I am seeing:

SSID: "*******" (2.5 Ghz)
RSSI: 0 dBm SNR: 0 dB noise: -90 dBm Channel: 10

SSID: "*******_5G" (5 ghz)
RSSI: 0 dBm SNR: 0 dB noise: 0 dBm Channel: 108/80

So something happened and the wireless restarted - I wonder what..?

 

[ColinTaylor]

What is a RCD device ?

https://en.wikipedia.org/wiki/Residual-current_device

(I'm too old. I still call them earth leakage circuit breakers )

 

[ColinTaylor]

Jun 8 21:25:47 rc_service: httpd 264:notify_rc restart_wireless

That's interesting. It kind of suggests that the wireless was deliberately restarted from the web interface (httpd). On the other hand you said "the issue has been the same with a number of routers" which would imply that it's something external to the router.

As @degrub mentioned, how reliable/stable is your power supply?

What sort of WAN internet connection do you have?

 

[p3ter]

any motor starter will broadcast white noise during the closing of the power contact. That means all frequencies. If you have a tv antenna, you may pick it up there and see it on the screen as a noise burst. Refrigerators, washers, dryers, anything with a motor. The noise will be radiated and will be pushed onto the power system.

30 seconds is way too long for that though. The AP device would be expected to accept all interference so radiation should not be the issue. Sounds more like a process restarting in the router, particularly if all models have the same issue. i would put a power isolator (ferrite core transformer, not one of the UPS things) if you can get your hands on one. Otherwise, put a surge arrest/filter device on the power to the router.

Makes sense and agrees with the logs as per my previous reply. I will look at some kind of isolation and see if it helps.

a floating ground level will play havoc with computer equipment if it gets above the limit (+ or -) of the diodes providing isolation.

Are the house plugs 3 wire (H,N,GND) or 2 wire (H,N) or is everything 240 V (H,H,N)

The house plugs are 2 wire 230V 50hz (i'm in Europe), I think the main fuse box from is from 70-something, but the actual house wiring is porcelain/Bakelite etc and a lot older.

what is the rough direct air distance to the 10 kV AC lines ?
That should be a constant electric field strength, not particularly variable.

I'm going to guess 25-30 meters, not exactly sure.

What is a RCD device ?

Yeah as Colin said lets just call them circuit breakers, but my understanding is that they make my ancient house wiring a teeny bit less of a death trap without the cost of rewiring the whole house. e.g. if a panel heater/radiator electrical fault caused the metal casing to become live, a house with circuit breaker and a normal earth connection would blow immediately. Since this house wiring doesn't have an earth connection, the radiator housing would will remain live until I touch it; electrocute myself, and then the breaker will spot the potential difference and throw the fuse (hopefully fast enough to not kill me). At least that's how I have had it explained!

 

[p3ter]

That's interesting. It kind of suggests that the wireless was deliberately restarted from the web interface (httpd). On the other hand you said "the issue has been the same with a number of routers" which would imply that it's something external to the router.

ahh, now you come to mention it I remember going into the router admin when the wifi died. There's only a couple of those entries in the log and they coincide with dates where I was at the house, so probably that last log entry was me fiddling about. If that's the case, there are no other logs from around the time the wifi dropped.

As @degrub mentioned, how reliable/stable is your power supply?

Good question - we don't get power cuts so often, the 1Kv line was actually upgraded this spring from non-insulated cables to insulated. Previously there would be power cuts fairly regularly during storms, but nothing recently. This is a small farming community, and I share the nearest transformer with a couple of farms and a handful of homes, but that's it.
I have noticed some other issues - e.g. I once tried using LED light bulbs and got some weird flickering, gave up and went back to incandescent/halogen. Since then however I have added a couple of LED bulbs without issue. I have had a USB charger blow, and the same charger seemed to have a high-piched whine on no load which was not present using the same charger at other locations. Otherwise no huge pattern of equipment breaking or anything.

Do you think something like this might help?

https://www.apc.com/shop/bg/en/products/APC-Essential-SurgeArrest-1-outlet-230V-Germany/P-PM1W-GR
Surge Protection and Filtering
Surge energy rating 918Joules
ts_nm_surge_response 1ns
Peak Current Common Mode 24kAmps
Peak Current Normal Mode 12kAmps

if so, I can pick one of those up for a reasonable price and see if it makes any difference.

What sort of WAN internet connection do you have?

WAN is 100-100 Mbps fiber over a Gigabit fiber link - (yes, I have gigabit fiber supplied to a cabin with no earth on the power supply, no indoor toilet, and hand pumped water from a well 100 meters away - go figure..!).

 

[ColinTaylor]

Do you think something like this might help?

if so, I can pick one of those up for a reasonable price and see if it makes any difference.

It might but those devices only really filter out very large transient spikes in the mains. I would look to see if you could get a UPS that provides a "stabilised" power source. Maybe something from APC's Easy UPS or BACK-UPS range. (Disclaimer: I have no personal experience of either of these products)

"APC Easy UPS is a versatile UPS developed to handle inconsistent power conditions.."

"Models supply battery backup during outages and unsafe voltage fluctuations, as well as provide protection from damaging surges and spikes."

EDIT: Maybe this: https://www.apc.com/shop/bg/en/products/APC-EASY-UPS-BV-500VA-AVR-Schuko-Outlet-230V/P-BV500I-GR

 

[ColinTaylor]

This is a small farming community, and I share the nearest transformer with a couple of farms...

That could be the source of your problem. Farm equipment can cause havoc with the power supply.

 

[degrub]

yep, second that. Anyone running milking machines or water well pumps nearby ?
Make sure the UPS doesn't require a ground connection on the plug. The 120v ones in the US do.
A fully floating system with no safety ground then. Keep your rubber non-conductive wellies on at all times then. Should provide some insulation to earth for your body.

 

[ColinTaylor]

Make sure the UPS doesn't require a ground connection on the plug. The 120v ones in the US do.

Yes, I was wondering about that. Those APC units I was looking at obviously all have 3-ping plugs, but whether it would work properly (at all?) without an earth connection... Definitely a question that needs to be asked of APC before purchase then.

EDIT: https://www.apc.com/uk/en/faqs/FA157422/

@p3ter Can't you just drive a 6 foot copper stake into the ground somewhere?

 

[p3ter]

Anyone running milking machines or water well pumps nearby ?

Yup, milking machines, hayloft fans, deep well water pumps, you name it...
Come to think of it, the nearest farmer has problems with his WiFi too (I gave him my old router) , and I am pretty sure he has an old 3 phase motor on his milk cooling compressor which is on its way out... Would be interesting to see what protection my electricity company offers from problems from other consumers on the same transformer.

Can't you just drive a 6 foot copper stake into the ground somewhere?

Haha yes of course I could, in fact the current location of the router after the last move is just a few meters away from the main consumer unit, so I could add a proper earth connection... But then I need to rewire all the sockets in the house, (it's not permitted to mix & match) and I'm not looking forward to that...

I just Googled a bit on the need for earth on a UPS, and it seems that it it not necessary for correct functioning of the UPS. I guess I need to spend a bit of cash and see if things improve. Thanks both for the input, I will try to remember to come back and give an update!

 

[degrub]

you might tell them what both of you are seeing and ask what their engineers would recommend as a solution.
They may just say it is not their problem.
if you can borrow a recording power monitor suitable, you may learn if it is noise / droops / frequency / over voltage that is causing the issue. Might give a better idea of a solution.

 

[Smokindog]

Ya, do NOT mix ground potentials

I've got some pretty dirty power in my area, thought nothing like you guys are describing!

I use these on my smaller network devices (APs/switches/...) and they help a lot. Can be had for about $20 on sale at newegg. I set them to the most sensitive mode.
https://www.apc.com/salestools/AHUG-9EACJU/AHUG-9EACJU_R0_EN.pdf
https://www.newegg.com/apc-bge90m-nema-1-15r/p/N82E16842301444?Item=N82E16842301444

I use a "full size" for y modem and main router. This one can be had for $100-110 on sale. Again, I set it for most sensitive mode.
https://www.newegg.com/cyberpower-gx1325u-nema-5-15r/p/N82E16842102238?Item=N82E16842102238