Things to note doing this:
Need a quality iron and decent solder skills
Keep the wires as short as possible, and try to make the D+ and D- as close to the same length as possible
Dont forget about the ID pin for the OTG off the phone micro USB, this has to be grounded.
Going to need a switch, both to save power and deactivate the OTG so you can charge. There might be a better way to do this but I didn't bother as this works.
The wiring on the switch I used (might be a better way again) was one pole only the Ground from the phone, the other pole has both the ID wire from the phone, and the ground from the alfa card.
The rest is self explanatory I think. Dont forget glue on the connections to make it a bit more robust.
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