Question Wifi issue on 2.4Ghz band & ebay dispute - can someone solve this argument??

beastman

Member
I believe I have been sold a tablet (Acer, made in 2019) with a defective wifi antenna but would appreciate some experts confirming what I think so I would appreciate some input on this.

My home router has the 5ghz band disabled (Plusnet router with known issues causing conflicts and slowdowns). All my smartphones work well on the 2.4 band as far as downloading/streaming and youtube etc. I bought a 2nd hand tablet off ebay but I noticed lots of buffering and on testing the speeds I noticed painfully slow downloads but often acceptable upload speeds. I have 38 mbps download and 10 upload and on the 2.4 band I was getting sometimes as slow as 0.18 download. About 60% of the time the upload speeds were slightly better than the download speeds. After lots of head scratching and troubleshooting I realised I should try the 5ghz band. Here is a shot of 10 tests, the first 5 on the 5 band and the last 5 on the 2.4.


On the 5 band the device is normal but on the 2.4 its often useless for video. The ebay sellar is not recognising that these speeds make no sense. For further clarity here are pictures of the speeds I was getting on an aging smartphone:


and the crazy slow speeds on the tablet (the one fast speed is when I was stood next to the router):


As a test and to exclude the my Plusnet router, I have used my smartphone (LG G6) as a router instead by using hotspot/tethering mode and tested 2 other phones and then tablet. This is again in 2.4 band.So.....

The Tablet next to the hotspot/tethering mode phone = 55.1 download and 9.55 upload - the other end of the house this drops to a pitiful 0.67 and 2.22!

Another old smartphone = 53.5 download and 4.7 upload - the other end of the house this drops to a reasonable 34.4 and 4.19
A much lower spec smartphone (with Snapdragon 425 chip, possibly similar spec CPU to the tablet): = 44.4 download and 15.4 upload then drops only to 44.4 & 15.4

I know how I interpret those figures, but maybe I'm wrong!

How can it make sense in the last picture for about 60% of the time that the uploads were faster than the downloads?
How can the differences in speed make any sense, apart from it being faulty in band 2.4 The other phones are getting over 50 times the speed.

As I understand it, devices dynamically on their own change from one band to another as you move about the house, so if the tablet switches back to the lower band its then going to be painfully slow, with little I could do to resolve it.

If anyone can confirm my thoughts I'd be very grateful.
 

MaryWhitehouse

Active Member
If it's from eBay just return it as not as described. You'll always get your money back.
 

beastman

Member
But the loss of postage expensive postage costs! If I can get the numpty seller to understand its faulty then they are liable.
 

MaryWhitehouse

Active Member
You get postage back and they provide a label to return. Don’t stress just send it back.
 

RBZ5416

Distinguished Member
What channel is your 2.4GHz set to? Some devices aren't happy with channels higher than 11.

I'd apply any available software updates to the tablet & if still no go, raise a return as faulty. As @MaryWhitehouse says, it should be fairly painless.
 

mickevh

Distinguished Member
As I understand it, devices dynamically on their own change from one band to another as you move about the house, so if the tablet switches back to the lower band its then going to be painfully slow, with little I could do to resolve it.
They can - but beware of "Big Wi-Fi Myth Number 2" that Wi-Fi clients are "always hunting for the best signal" - they do not and some need the incumbent to get pretty grotty before they initiate a roaming assessment (whether they can and should change the AP they are Associated with.) Note that it is the client device that makes the choice, not "the system."

If you want to prevent clients roaming between wavebands or AP's automatically, then you could name the SSID's differently, but that means you will always have to flip between them manually. With dissimilar SSID's, client will only shift automatically when they completely loose connection and "start over" as if you'd just turned them on - that might be much further away than you might think.

A lot of the test you've made aren't really objective - for example using a mobile phone hotspot (they tend to have small antenna and be really miserly with the transmit power) or testing with all your other devices active. To be more objective, you'd have to turn off everything except the router and the test subject. Even then you might be getting interference from the neighbours and tablet devices (like phone) often have small and only one antenna and try to be particularly miserly with their transmit power which can affect performance.

If you really want to get into the "numbers game" you're going to need to do some research to understand the capabilities of both yout test subject and your router, then clear out everything else so it's the only device active while you test, then look for trend rather than absolute values (Wi-Fi is fickle at the best of times.)

However, I agree with the others - if you think it's defective, return it and demand your money back. The onus is then on the seller to prove it is as described.
 

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