Hi All
Whilst of course DJI will not approve of modding the Antenna on the Controller.
However besides those cheap folding slip on parabolic mirrors, there does exist several more involved mods that require you taking apart the controller  in order to replace the stock antenna with various higher gain solutions.
Has anyone done this yet?  
Have you ACTUALLY NOTICED a significant, or even ANY improvement in range, to warrent the replacement and expense?
Here are example pics of a panel directional booster (the company that make the panel DO have one out specifically for the Mini), & longer antenna ...
Mini-booster

bump bump bump

Waste of money. You can find some stuff on youtube about them but the difference if any is minimal. Use the parabolic ones, do the same thing and don't void warranty etc.

I suspect that any limitations are more likely with the antennae of the mini rather than the remote since the antennae are much larger on the remote.

yes and no, my experience is using antenna mods on Mavic air which is also Wifi., i had a 9Dbi gain antenna mod i used, no amp, which where just long antennas and results where mixed..  sometimes range was much much more noticeably better and more reliable and was able to get more things between me and the drone before signal fell off a cliff and other time it was about the same or oddly worse and was not much of  pattern i could gather.. overall, yes it was better but no it isnt worth the extra fighting and fuss looking in the long run... the only reliable thing i noticed about using antenna mods were that telemetry data came in instantly upon regaining signal like battery life, distance, point on map, and all details even if picture failed to come in..   2,4ghz or 5.8ghz..

that being said my experience is with a different drone, controller and app, it is possible results will be different with mavic mini, though i doubt it, Wifi is Wifi and just prone to signal integrity issues and signal quality issues and honestly isnt a technology any drone should be using, specially not something ay DJi drone should be using given all their other technologies...

Topic was discussed recently in another thread.

As an ignorant I ask a question: if I can enhance the signal from the controller to the drone and not vice versa, what's the use?

Renato61 Posted at 4-29 21:32
As an ignorant I ask a question: if I can enhance the signal from the controller to the drone and not vice versa, what's the use?

Apparently they are supposed to enhance the reception ability of the drone's return video signal as well.

120ccpm Posted at 4-29 21:18
Topic was discussed recently in another thread.

Hi, many thanks for the link.
Given your reply in the other thread.  What 'omni antenna' would you reccommend?

Renato61 Posted at 4-29 21:32
As an ignorant I ask a question: if I can enhance the signal from the controller to the drone and not vice versa, what's the use?

https://deepspace.jpl.nasa.gov

PhasedSpaces Posted at 4-30 02:05
Hi, many thanks for the link.
Given your reply in the other thread.  What 'omni antenna' would you reccommend?

Here is the original post on PhantomPilots with additional details.
I started with some cheap 6dBi omnis from eBay, dual-band (the P3S uses 2.4GHz for the video downlink, 5.8GHz for the control signal), but they weren't great. I then switched to some better ones, probably more true to their "6dBi" claim, but I don't recall where I got them. If you Google around, you will find hundreds of them. The beauty of this mod is that, once you have RP-SMA connectors on your RC, you can change antennas in a second, and try different ones.
One comment about frequencies: I see you're in the UK, so you would need dual-band antennas (2.4 and 5.8) because your MM supports both. The FCC version of the MM runs on 5.8Ghz only.