I am currently using a 4G mini hub while my broadband is fixed ( long story involving neighbour, gardener, 20 pair cable and the need for traffic lights to dig up the road!).
I have discovered that If I connect it via USB to my PC (which has no WiFi) it appears as a Remote NDIS based Internet Sharing Device, and successfully connects the PC to the internet. However speed tests show a download speed of about 30Meg. If I replace the Hub with my (android 6) phone in USB tether mode to the 4GLTE network, I can get 70Meg.
I get the same 30Meg download with a WiFi device connected to the hub using the 5Ghz channel.
Is there a speed limit imposed on the 4G mini Hub?
I asked the same question when three days ago, 02/08/2022, my Full Fibre 900 developed a fault.
To BT honour, they quickly activated my 4G Mini Hub (the "71" version), which I had stored since my last time I had a fault (long, long time ago), -- and stopped accounting traffic on my 2 mobile phones (under Family Plan).
By using speedtest.net on my 4G phones and 4G Mini Hub, I was able to discover that Mini Hub's rate limited at 30 Mbps down and 15 Mbps up. At that, my phones consistently were able to surpass 200 Mbps at the same place. They are BT Mobile SIM Only family plan members, and are not limited.
I remember that a coupla' years ago, single speed EE connection was limited at exactly that: 30 DN / 15 UP. And "Double speed" -- twice that, 60 DN / 30 UP. Only the contract mobile owners had unlimited 4GEE speed, I think.
I rang BT Support at 150 and raised this question alongside my own super question "when are you going to fix it?"
The BT Support operator was so kind as to call EE team and try to understand what plan is the SIM card inside 4G Mini Hub on. They initially thought about sending another 4G Mini Hub, but I just asked "what would be the benefit? yet another rate-limited plan on another SIM Card". My suggestion was that it was a grandfathered plan and I asked if I can get an up-to-date plan applied instead of wasting time and money on sending me another mini-hub.
I tried suggested solutions such as
The answer was along the lines of:
1. " - We cannot change the mobile plan on 4G Mini Hub SIMs. That would lead to unequal treatment of different customers and potential problems."
From this I derived that they admitted there was indeed the limit.
2. " - If the customer (that is, me) has an additional, unused at the moment, BT/EE SIM card, they can stick it into 4G Mini Hub".
That amount to this: the card in 4G hub is just a free, 30/15 rate limited, Data SIM Only, activated and deactivated along the lines of developing/fixing the fault.
Those who wish a faster backup, will have to have this card paid-for.
(I wonder if there is a PAYG SIM available from EE, not limited by time, which can be used in such cases...)
Anyway, don't hold your breath. I think there's a reason they rate limit the backup SIM.
That said, I'll try to write a complaint to BT, saying that this is so 2019 and from ADSL era, to seriously think 30DN/15UP is a proper backup for a 900/110 Full Fibre line.