So you are going with what? Rb433's or the rb600?
Gino A. Villarini g...@aeronetpr.com Aeronet Wireless Broadband Corp. tel 787.273.4143 fax 787.273.4145 -----Original Message----- From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On Behalf Of Kurt Fankhauser Sent: Wednesday, April 29, 2009 10:34 AM To: 'WISPA General List' Subject: [WISPA] RB333/433 eliminating self-interference test About a week ago there was some discussion about 5ghz radio's being installed in the same board and causing self-interference on adjacent channels and possible even on the entire band thus decreasing throughput on backhauls. Because even if you were operating on frequency's 5745 and 5825 the two radio's would have side lobe harmonics that if installed in the same enclosure they would still "hear" each other at that short of separation. I decided to combat this problem and find a solution and share my experience with the list. I installed a single XR5 card into 3 different RB433's with indoor enclosures. I also installed foil tape which I obtained from the local True Value store for $2.49 on all the vent holes and unused bulkhead connector holes. This was done in order to prevent RF side lobe leaks from the three radio's that would escape from the indoor enclosures themselves. Having only 1 card inside each enclosures I should not have a heat problem as the outdoor box will not be in direct sunlight. I then stacked all 3 enclosures on top of each other with dummy loads on each of the N-bulkhead connectors and did some testing. This is what I found: I set the bottom board as AP and the middle board as Client on frequency 5825. Even with this close of separation the two XR5's could only see each other at -83 on the same channel. With the top board connecting to the bottom board they could only see each other at -90. Keep in mind this is on the same frequency so adjacent channels should be much less than that possibly even in the -100 ranges. Wish I had a spectrum analyzer. With two boards separating the AP and Client there was no link at all. The two boards could not even see each other in an AP scan. Just as a comparison with the same radio's installed all on a RB600 not on top of each other but in the adjacent mpci slots the radio's were all seeing each other at -30's. So I gained roughly -55 db of separation by doing it this way. So all I would have to do now is make sure that the antennas on the tower have at least 10 foot of vertical separation and the self-interference problem should be gone and I should be enjoying much more throughput! Thoughts anyone? Kurt Fankhauser WAVELINC P.O. Box 126 Bucyrus, OH 44820 419-562-6405 www.wavelinc.com -------------------------------------------------------------------------------- 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/