@Richard_Love did you ever find a router that was compatible with the Three UK 4g+ bands?

I am looking to replace their stock on which drops all the time even with full signal quality.

Hey, I see it from a different port, maybe it would be helpful before you bought the Archer MR600.

https://community.tp-link.com/en/home/forum/topic/205912

Thank you!

I wanted to just share my experience with Three UK and 4G+ and Carrier Aggregation (by the way 4G+ does not always equate to CA)

Ive been installing Mikrotik LHG-LTE6 dish for customers with poor broadband or in rural areas. Three mobile broadband is a good choice because the user gets a real WAN IP. The product works great and initially - maybe around October 2020 I saw devices get CA straight away and really great speeds - 50-90M down and a consistent 30M up.

Around April 2021 this changed and I saw CA being dropped progressively more and more. Eventually CA was never seen again. I blamed the device for a long time but Im now pretty certain Three have changed something (unpublished) on their towers such that its making decisions about what will be offered to devices. I spoke to the manufacture extensively and had several test firmwares to try to consistently get CA but in the end they said that the towers are ultimately in control of allocation of CA bands to devices.

I did some tests on a small number of towers that have B3,1 & 20. My phone got CA every time (OnePlus 6 not officially supported), but the Mikrotik device did not. I verified it was CA and not just 4G+ by using NetMonster app. 4G+ can in some cases simply be a high bandwidth single band connection.

Three are mainly B3@15M, B1@10 & B20@5M. B3+20 and B1+20 are supported by the Mikrotik hardware, yet seems to be denied CA as of this date despite proof that the towers give CA out to a phone. I spoke to Three technical support several times describing the issue - both their 1st line "device" support and the 2nd line "Network" support. All were very frustrating long conversations (3hrs in one case) and I came to the conclusion that even the 2nd line support are not really technical. They look on their screen and tell you if theres a "problem" at the tower but dont know anything beyond that. They didnt even know what "Carrier Aggregation" was. Regarding one tower they said that the signal for the area post code it was covering was not ideal and kept blaming poor signal despite me explaining repeatedly that I had a high gain dish mounted on the roof pointed at the tower and quoted them stellar signal from the dish diagnostics -  they were useless. I probably need to speak to some dept that deals with device certification but I cant find any publicized contact details to get beyone the 2nd line support wall.

So Im at a loss as to why a capable device is not assigned CA. Three have made some undisclosed change to their network that makes this decision. The same mikrotik device on O2 got CA immediately. Ive yet to test with other networks. Someone in some back office at Three has the answer. Finding them and getting answers is going to be problematic.

bigM wrote

My experience using the MR600 reflects this. I was getting a 4G+ connection until Three did "upgrading" work on the nearest mast several months ago. Since then it's only 4G.

@bigM That's exactly the same as my experience. Was getting 4G+ on band 3 and 20. Then had SMS message saying Three was doing upgrading work and since then I only ever connect on one band, usually band 3 by default.