There is nothing wrong with lowering the power on them. I personally love SR5s.
The facts are though that cards with add-on amps embedded have the potential to be noisier than one that does not. How much noisier, I can't say. That was part of tthe goal, to determine if XR5s are as clean as CM9s, and if there is a distinguishable difference or not. Tom DeReggi RapidDSL & Wireless, Inc IntAirNet- Fixed Wireless Broadband ----- Original Message ----- From: "Kurt Fankhauser" <k...@wavelinc.com> To: <wireless@wispa.org> Sent: Wednesday, April 29, 2009 6:30 PM Subject: Re: [WISPA] RB333/433 eliminating self-interference test > > Whats wrong with using XR5's and lowering the TX power on them? They are > more rugged and have better RX sensitivity than many other cards. > -- > Kurt Fankhauser > WAVELINC > P.O. Box 126 > Bucyrus, OH 44820 > 419-562-6405 > www.wavelinc.com > > > --------- Original Message -------- > From: WISPA General List <wireless@wispa.org> > To: WISPA General List <wireless@wispa.org> > Subject: Re: [WISPA] RB333/433 eliminating self-interference test > Date: 04/29/09 16:31 > >> >> The first question is "why are the 4 mpci cards in teh RB600 seeing > each >> other so loudly"? >> There lies the problem needing fixed, because of course we want to use >> one > >> RB433, instead of 3 RB433s, to accommodate 3 mpci cards. >> (even if different channels and freqs). >> >> First question to you... "am I assuming correct that you still kept > the >> dummy loads on each of the mPCI cards, when testing all in teh same > RB600"? >> >> What is a bot disturbing is that you said you used a XR5. That means the >> card had a single antenna connector and a MMCX style, which is supposed >> to > >> give better isolation. >> >> (note: some have advocated that Ufl is as good as mmcx, regarding rssi > loss, >> stating that the UFl connector itself has less loss than the gain MMCX > adds >> by enabling thicker pigtail cable. I always still prefer MMCX because it > is >> more rugged abd less likely to break pigtails connectors in things like >> Rootenas that are not easy to access with short pigtails. But surely I >> thought mmcx would also add better shielding/isolation from outside >> sources.) >> >> So using XR5s, it would infer that the cards saw each other because >> either > >> loss from pigtail cable, loss from mmcx connector, or simply the cards >> electronics. >> The next relevent info might be to determine if it is the amp circuitry >> driving this interference. Just like a pair of PC speakers can sometimes >> pickup music radio. >> >> For years Lonnie (StarOS) gave teswtimonials for lower power CM9s > performing >> better than Amplified cards (SR5) for short range applications, because > they >> were quieter. >> >> So there is about 8db difference between a SR5 and a CM9. I wonder if you >> repeated your tests, but used CM9's instead (no ext embedded amps), > whether >> you'd just hear the other adjacenet radios at 8db lower, proportional to > the >> spec of the radios, or if you hear the otehr radio much much less, >> because > >> it doesn;t have the amp to pcikup the interference? >> >> >> Tom DeReggi >> RapidDSL & Wireless, Inc >> IntAirNet- Fixed Wireless Broadband >> >> >> ----- Original Message ----- >> From: "Kurt Fankhauser" <k...@wavelinc.com> >> To: "'WISPA General List'" <wireless@wispa.org> >> Sent: Wednesday, April 29, 2009 10:33 AM >> 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! 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