Hello,
there are many possible causes for this. But out of my experience theses are most common:
- Building or treee in the way of transmission. There is a "Fresnel Zone" around the straight line-of-sight, which should be free of obstacles, too. Check if there is enough free space in this area.
- Other WiFi-devices installed recently. Maybe a neighbor near one of the bridges just added a WiFi-device on the same channel. Check via AirMagnet or use 802.11a with DFS (Dynamic Frequency Selection).
- Other Non-WiFi interference. Some devices like production machines or Wireless video cameras interfere with 802.11g. You could check that via Cisco Spectrum Expert or just use 802.11a.
Hmm, that's it for now. Sorry, if i forgot something.
Greets,
Sebastian