Hello,
I recently got a Belkin F5D7011 802.11g PCMCIA card (Broadcom 4306
chipset), and I've found the built-in antennas to be really poor. I can
barely stand 20 metres away from my AP before the signal conks out, and
my AP has two extra-strength external antennas connected. My old
wireless-B card works fine at a much farther distance anyway. So I've
taken on the task of attaching an external antenna to this card, which
doesn't have an SMA connector to accept an external antenna.
I have a 7dBi "High Gain Antenna" by Linksys with an SMA connector.
Apparently Radio Shack in Canada (now Circuit City) doesn't supply the
opposite SMA connector I need to plug this antenna in, so for now I'm
making do without one and just connecting the antenna via copper-coated
wires (my resources here are very limited). See a photo of the antenna
and wires here:
http://open-eyes.org/loft/gallery/ga...in/antenna.jpg
I've taken the card apart and I've located the two built-in antennas,
and also an array of 5 contacts which seem to be designed to accept an
external antenna connector (I've seen the same pattern of contacts on
other wireless cards and diagrams on the Internet). I used a hobby
knife to cut the circuit to the existing antenna on both the top and
bottom of the card. Then, rather than soldering the 2 wires to the
antenna directly to that 5-point contact with my crumby soldering iron,
I figured I could just connect it to any points along the existing
antenna, since it's easier. The 2 wires are connected to points on
either side of the spot where I cut the circuit.
Here is a photo of the top of the card:
http://open-eyes.org/loft/gallery/ga...%20kin/top.jpg
.. The five contacts for the external antenna connection are boxed in
red, and the point in the circuit that I cut out is circled in yellow.
Here is a photo of the bottom of the card, where I also had to cut out
part of the circuit to the old antenna:
http://open-eyes.org/loft/gallery/ga...kin/bottom.jpg
However, I've found that with the external antenna connected this way,
it seems to make no difference in the signal level. I'm running Linux,
and I use iwconfig to tell me the signal strength of the network I'm
connected to. The signal seems to vary between -37 dBm and -58 dBm at
my testing location (which is only about 2.5 metres away from my AP).
But when I have the external antenna connected, or when I even just
leave the antenna circuit broken, it makes no difference to the signal
strength; it just varies within that range as usual, usually sticking
around -40 dBm.
Does anyone here know why this modification has made no difference? I'm
so inexperienced with modifying circuitry, so maybe someone more
experienced here can see a problem with how I've done it.
I assume "signal level" is the reading I should be interested in,
rather than "link quality" or "noise level", because "signal level"
seems to be the only one that decreases with distance. The other two
readings are always very good and stay about the same regardless of
distance and obstacles.
Thanks in advance for any tips you can offer me.
Cheers,
Paul
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