Finally got around to setting up the external antenna modified 703n as a solar powered 3G relay site.
I have a Sierra 320U Modem + 703n (running OpenWRT - ROOter), remotely located and solar powered.
I am using the 703n WIFI (AP mode) to provide a link to a TP-Link TL-WA701ND V1 (Client mode) also running OpenWRT.
The WIFI link path is 600m from the relay site to the farm house.
A few pictures is worth a thousand words.
I had two 19dBi 2.4Ghz grid packs 'lying around' so I've pressed these into service.
Initially the level was too hot driving the receiver into overload, reducing the link throughput.
I reduced the Tx power in both routers to 10dBm in lieu of 20dBm) and it is now fine. A couple of 10dBi (rather than 19dBi) antennas would be perfect for this link with the AP's at full power. In fact with the AP at full power I could happily connect directly to the relay site with a laptop at home on the patio. That's pretty neat 600m for a humble 703n.
The following screen captures show the link levels etc.
As you can see the Rx levels of both routers are identical.
This antenna mod works exactly as it should.
PS the sky is blue coz I'm in Oz.
PPS the power requirements are tiny. A 40W solar panel runs the show with ease.