Dingoonity.org

I dont believe the 7800 supports 5ghz thats why there is only one antenna. That doesn't mean you wont see benefit from router if using multiple devices at a time. As 2.4 gets crowded other capable device will to use 5ghz . The slightly higher dba antenna will help but at cost in directionality . Of course a better made quality might do better full cross the board. Read about how to install them as well i think the benefit from  the ground area on meta larea or battery not "necessarily grounded on it " and antenna area sticking out from it.

A small pen type iron, I like 70tin-30pb rosin 60-40 ok too, tin wires first ,keep tip clean and tinned. Old solder sometimes the rosin receded back into hollow of solder ,so waste a little. On circuit boards faster is better if you linger too long coatings contaminate the job. Get a bump on pads"contact points" of solder, tin wires first lay on bump. melt together. An extra set of hands never hurts in this case probably not necessary. A good job looks shiny as it cools without wire moving in the process.

I haven't found yet a workaround to use the wirelless usb key with OTG.

So i have test to rework antenna's solder and move the antenna in another place.
Signal is more stable but still have too much high and low signal transfert ... until I'm moving the device in a particular position from my routeur => OMG  !! perfect signal

3-5 ms ping, no more paquets lost
I was able to remote streaming my computer's games on my S7800 flawless.

I don't have this kind of problem with my wifi laptop at the same place.
The JXD antenna isn't suppose to be multi directionnal ?

I will try to change the antenna for a better one, maybe an external antenna is a good idea.