You are missing the point.... Its not an issue of having to high of TX power. Its an issue that AMPs are noisy and amplify noise they hear.
Turning an XR5 amp down does not necessarilly solve the problem, as the amp still hears noise to inject into its output. If radios are clean, and cabling solidly shielded, there shouldn't be so much RF leakage. I'm starting to wonder if someone should make a small thin lead plated plastic case, the size of the mpci card, than snaps around the MPCI cards, while in the mpci slot, to minimize the RF leakage? I guess what I'm getting at..... Shouldn't we be understanding where the RF leakage is getting leaked? So our conclusion can be "how to fix the problem" apposed to "how to work around it"? Tom DeReggi RapidDSL & Wireless, Inc IntAirNet- Fixed Wireless Broadband ----- Original Message ----- From: "Scott Carullo" <sc...@brevardwireless.com> To: "WISPA General List" <wireless@wispa.org> Sent: Wednesday, April 29, 2009 4:51 PM Subject: Re: [WISPA] RB333/433 eliminating self-interference test > How about just decreasing the xr5 power level to about 200mw > > I wouldn't put a cm9 on a tower or so > > Scott Carullo > Brevard Wireless > (321) 205-1100 x102 > > On Apr 29, 2009, at 4:31 PM, Tom DeReggi <wirelessn...@rapiddsl.net> > wrote: > >> 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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