The card is based on AR5008 chipset with 802.11N MIMO capability.
That means it can use multiple antennas. But it would depend
on how they were configured, as to what antenna has what function.
For example, changing the RF section of the design, could support
more or fewer antennas. I don't know if every antenna is a
transmitter, especially when backward compatible with previous
Wifi standards. The other standards might not have MIMO, and
then one of the antennas might have more functions than the other.
See "Number of antennas" for hints.
http://en.wikipedia.org/wiki/802.11n
If you look at the card layout, the upper antenna has a
simpler set of surface mount components than the lower one.
I'm *guessing* the lower antenna is a transmitter at the
very least. If I only had one antenna, I'd connect the antenna
to the lower connector, just based on the complexity of
the "analog chain".
http://images17.newegg.com/is/image/newegg/33-124-297-Z03?$S640W$
But I would also connect a terminator to the other, open connector.
It's just the kind of guy I am.
You really need to find out the connector type, available on
the face of the card. They do make replacement antennas,
but they have caveats. For example, this pair (about $25 when
on sale and probably not worth it), are omnidirectional in the
horizontal plane. These extend the gain, *on the same floor*,
but would make it harder to reach a wireless router in your basement
(below you) or on the second floor (above you). So the higher
gain, is a lobe pattern extending in the horizontal plane.
That's what one reviewer of this product, claimed.
http://ec1.images-amazon.com/media/i3d/01/A/man-migrate/MANUAL000069509.pdf
You'd search for an antenna, with matching connector type (as the
connector type, also implies a characteristic impedance - one
connector type might suit 50 ohm usage, another type
75 ohm usage and so on).
Your two connectors could be "RP-SMA" but I've lousy at
identifying those things. If this photo had been on just a
slight angle, it might have helped. Antenna kits come in
a number of different connector types, like maybe TNC, so
it's a jungle out there.
http://images17.newegg.com/is/image/newegg/33-124-297-Z02?$S640W$
Picking up some little USB Wifi dongle, with integrated antennas
(patch antenna right on the PCB), is another alternative. It
all depends on how bad you want to connect to that router.
For example, $20 and you're done... This is better than buying
an antenna kit, because it's a whole product and ready to go.
"TP-LINK TL-WN722N"
http://www.newegg.com/Product/Product.aspx?Item=N82E16833704045
Paul
