20dB variability of wifi signal

[kolofarthos]

Recently been having problems with wifi connectivity. No recent changes to wifi set up or laptop.

Sometimes the wifi signal goes low by 20 dB for while. Wondering if it is due to the hub getting too warm. It is quite warm to the touch. Bt wifi is on but not needed. Would that affect temperature?

It is a bt hub 6. Signal has been monitored via a tablet using wifi analyser. No channel conflicts on 2.4 or 5GHz bands. The problem is really only when at a distance of about 15m from hub when 2.4GHz level drops from -55 to -75dB. 5GHz channel too low at that distance and via several wall. Closer to hub no problems as signal level is adequate.

Any ideas or settings that might affect the problem. Or could it just be a dying hub?

Isolated location so no other channels of significant level and they are very very low.

Cheers

[rbz5416]

Could be interference from another device. There's any number of wireless things operating on 2.4GHz or spitting out interference. So it could be worth trying another primary channel (1, 6 or 11).

Can the Hub be relocated more centrally? If not I think I'd be inclined to add an wireless access point.

Smart Hubs are cheap to pick up used so you could always try a replacement if you wish, then use it as a WAP if it makes no difference. Although a proper WAP would be preferable.

[kolofarthos]

Thank you kindly for your response.

All very sensible suggestions.

To clarify a bit, I have already changed from the original channel 11 (it was selected automatically) to channel 1 and there was no change. This is in a property with no others within about 30m so there really ought not to be other wifi signals of any significance interfering. That is shown to be the case with max signals shown on the wifi analyser app, at any position in the property, at no more than about -90dB and quit rare.

However other interfering signals maybe ought not be discounted. A tablet based analyser is not a full Radio Frequency spectrum analyser so might be missing other sources in the band. I must check if that is the case.

I do have good spare hub so can try that out in line with your suggestion.

It would still be good to know, if anyone can help, whether the WiFi transmitter is throttled if it overheats or has another problem as a 20dB signal variation between fixed points is big. It is not ny property that has the issue but I have for my own use an identical and other similar hubs and (using the same tablet/analyser) they do not exhibit such variation - and that is in a noisier environment.

So a few more things to check......

Thanks.

[Les-Gibson]

Does this happen during any specific event? for example microwave ovens work on 2.4GHz

[kolofarthos]

That sort of interference is certainly something that should be considered....

But as far as I know there is nothing interfering when I last tested for levels.

However I hope to test with a different router today. It is one I know is working well and gives transmission signal kevels closely matching two others I have available (all within about 5dB). Will set up as a wifi repeater (on a different channel) fed via ethernet from the bt router so I can compare side by side. That should tell a lot.

[kolofarthos]

Aha! Progress!

The 20dB variation does not really exist, it seems. The response time of the wifi analysers I have been using on my tablet is slow, even when setting to the most rapid update! Not sure if it is the app or maybe the tablet slowness. The original router and repeater are nearly identical in level and variations.

Coupled with that minor position/time changes show up other low level signals (all wanted and unwanted signals, i.e. noise, in a low level range below -70) coming and going - producing a poor SN ratio.

Positioning the router used as repeater better/closer improves the signal enormously such that the 5GHz band is more than adequate rather than the 2.4GHz being the only workable and low and marginal.

The above is probably not helped by the amount of metalwork in the building!!

The way forward is now obvious! Re position the router or use a wireless repeater. Unfortunately using ethernet or power based extenders is not posible in this case.

Thanks contributors helping my brain be more logical!!

[Paul608085]

@kolofarthos 

To add to your findings about the WiFi Analyser app:

Assuming that we are talking about the same app, (there are so many!), then I have the "Pro" version of it. I don't know if that makes any difference?

What I found with it was that rather than getting 20dB reductions in signal strength, it would indicate complete loss of the WiFi signal every couple of minutes or so, for about 15 seconds, on both bands.

I spent some time investigating this before I realised that no one else in the house was complaining about intermittent WiFi. They were using laptops running Linux Mint and Android tablets.

Like you, I came to the conclusion that it is either the app or the tablet I use it on that was actually causing the "problem".

[Les-Gibson]

I've been using WiFi Analytics by Netgear for years, it's good, reliable, free and most of all -- No Adverts!