2.4 Ghz 24dbi Grid Antenna No Signal!!

I think the cable IS your problem.

What I prefer would be an Ethernet to wireless bridge near your antenna with a short pigtail, powered with POE. You could put it in a water tight box or under an upside down bucket.

My opinion

Although I think the cable is the most likely problem, another possibility to bear in mind is simply that your antenna might not be pointing the right way. It is far more directiional, so you should not be getting all the APs at the same time.

Does it look assembled like the one in the photograph? I've seen them mis-assembled with the feed rotated 90 degrees with respect to the reflector. That doesn't work.

Ok, the card has an RP-SMA connector.

The range depends on where you point the antenna. You should get more range but not to the side or back of the antenna. If you're just pointing the antenna is some random direction, you'll only hear stations that are perhaps within +/- 5 degrees of where you point the antenna. If you want to check *AREA* coverage, you have to rotate the antenna in a full circle, slowly.

I'm suppose to guess the coax type. I probably could, but I'm lazy. So, I'll guess. Is it LMR-400? Did you make this cable yourself, or did you buy it from a reputeable vendor? Is there a pigtail involved? You might want to check for construction errors on the coax, such as a short to ground or a missing center pin. 2.2dB of loss will be noticeable but far from fatal.

There should also be a pigtail involved to go from the LMR-400 to the small RP-SMA connector. Have you checked it? If there's no pigtail, and you built or bought an RP-SMA connector to go directly into your PC card, there's your problem. Those connectors last about 30 seconds after installation thanks to the extreme bending on the RP-SMA connector. Inspect, and I would not be suprised if it were falling apart.