Thanks for the info but I'm not sure you can compare apples to apples because you had 3 separate units, not multiple radio boards in one RB. You should have used RB411s you would have saved money, power, heat and space.
Scott Carullo Brevard Wireless 321-205-1100 x102 -------- Original Message -------- > From: "Kurt Fankhauser" <k...@wavelinc.com> > Sent: Wednesday, April 29, 2009 10:36 AM > To: "WISPA General List" <wireless@wispa.org> > 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/ -------------------------------------------------------------------------------- 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/
