Mac mini having trouble connecting to wifi

Hi all, i have a problem with my mac mini, and have done ever since i bought it. Basically for Wifi connection the unit works fine over 5Ghz band, but on 2.4Ghz wifi it is completely useless. I

I have a macbook pro from mid 2012 which only has 2.4Ghz wifi, and i am currently using this to connect for this discussion because my mini simply will not connect to the wifi router again. It seems to happen if there are multiple other signals around, maybe that are all using the same frequencey for Wifi, and i assume the router i'm using is also 2.4Ghz wifi because my macbook can connect to it, and my mini seems to have a lot of trouble. I am currently in a block of flats on holiday and can see several other signals around, and am using a rented wifi hotspot Huawei hippocket wifi unit.. Anyway, i would rather be able to use my mini than my old macbook pro, can anyone help with this problem? I have successfully connect to the wifi router multiple times using the mini, but it seems it just decides it doesn't want to play ball for no apprent reason (other than the multiple other signals around). And there is clearly no issue with the wifi signal as i'm currently connected on both my phone and macbook pro. Thoughts anyone?

[Edited by Moderator]