I have had a strange problem crop up. A few days ago I had a link that was working perfectly go crazy

on side A I get tx/rx of -74/-90

on side B I get tx/rx -90/-74

The antennas have not moved and have been up there for a year at least. I would check the cable and all that.. but I am confused about the lopsideness of the connection. If it was a cable then the it would affect both tx and rx.. it seems to me this must be a bad wifi card... but I would like feedback from all the other smart folks here before I go climbing towers in the rain. If I am going to fall from a tower, I want to be up there for a good reason
Also, based on this which card would I replace? A or B?

I would go for side B first , had this happen here last week after heavy rain for few days (rains a lot here) except there was 3 client connected to the antenna, it showed almost normal rx strength from all 3 was down but the rx at each of them was down 10db . It is probably a tiny bit of moisture in the cable/connector , not enough to kill it , just enough to bring it down.

And I have had a similar strange problem crop up. On both sites A and B I get tx/rx of 6Mbps/54Mbps. When Bandwith test transmit, cpu usage goes to 100%

We recently had a similar problem, the difference was only about 7-9 dBm, however the culprit was a bad pigtail on one side at the u.fl antenna connection.

With the pigtail replaced rx/tx is the same or within 1 dBm.