If you want more wireless-range, buy another device. I don't recommend soldering additional antenna on a WR703N.
These ones TPLink WR842ND (watch for usb port) has 2 big external antennas and are cheap too.
On this device you are able to exchange the antenna to something different with a simple standard-"port".
I don't believe such an antenna like the HDMI antenna will work well, because it is not only receiving data, but also sending.... and you maybe damage your radio....
Matthias
These ones TPLink WR842ND (watch for usb port) has 2 big external antennas and are cheap too.
On this device you are able to exchange the antenna to something different with a simple standard-"port".
I don't believe such an antenna like the HDMI antenna will work well, because it is not only receiving data, but also sending.... and you maybe damage your radio....
Matthias