Your probably seeing tidal dropouts. We have that problem from time to time and usually a larger antenna does the trick with a narrower beam.
I would go to 32 dbi dishes at HPOL (I think H-Pol works better over water from experience) I would probably look into use XR-5 cards for the extra output power at 5.8ghz. -Cameron -----Original Message----- From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On Behalf Of Jeremy Parr Sent: Wednesday, October 28, 2009 9:21 AM To: WISPA General List Subject: [WISPA] Long 5Ghz link over water I have a 23 mile link completely over water that I cannot get stable. One end is approx 200ft AGL, 220ft ASL, the other end is 50' AGL, 90' ASL. Antennas are V-Pol 29dbi grids, radios are R5H cards. I have tried the link at both 5.2, and 5.8, but it still fluctuates dramatically. When the antennas were installed and configured for a 5Mhz channel, I was able to aim them to -55, but still they go down during parts of the day. I have a second antenna hung on the 200ft end, at about 185', connected to a second R5H set up for H-Pol which I am going to light up as soon as I get the other end mounted H-Pol. Any other suggestions for getting this stable? I also notice some strangeness when doing bandwidth tests. I can get a steady 8mbps downstream from the 200ft end to the 50' end, but from the 50' end to the 200ft end, the transfer starts at about 6mbps, then slowly drops down to 0, and the client radio (the 50' end) drops. My assumption is multipath reflections off of the water at the lower end, but I cannot be sure. The water is tidal, with as much as a 3' change from low to high, and is connected to the ocean, so there can be considerable chop and wave action on the surface. -------------------------------------------------------------------------------- WISPA Wants You! Join today! http://signup.wispa.org/ -------------------------------------------------------------------------------- WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/