Rick: Why did it solve the problem? Better side lobe attenuation? 'Splain Lucy.
Mike At 08:42 PM 10/18/2009, you wrote: >I fixed a nasty multipath issue for one of my subs by using a yagi. >Here are some good sources for info: >http://www.wi-fiplanet.com/tutorials/article.php/1121691 >www.crystalcomltd.com/...whitepapers/124102032509Berkeley_Multipath.pdf >http://www.rfengineer.net/1171/rf-basics-multipath/ >http://www.cisco.com/en/US/tech/tk722/tk809/technologies_tech_note09186a008019f646.shtml >-RickG > >On Sun, Oct 18, 2009 at 10:51 AM, Marlon K. Schafer ><o...@odessaoffice.com> wrote: > > I don't Steve. > > > > But think of it like an echo. You get that first, clear signal coming in, > > laser straight. Then at some point shortly after that you start > getting the > > reflections. If there are too many of them, and/or they are at the wrong > > time the radio will get confused. > > > > G SHOULD handle this better than B. It's made to use multipath's echoes to > > reassemble a complete message. Sometimes it works that way, sometimes it > > doesn't. > > > > I'd have to say, for me, g is usually better with multipath than b though. > > B handles interference better. At least that's what I'm seeing. I have a > > tower that was giving 1 meg down 2 to 3 up, almost all customers > saw that or > > worse. Swapped back to b mode only and it's now a consistent 4 megs both > > ways. > > > > Another thing to try is to turn down the power. Probably on both ends. If > > you are at -69 see if you can drop your ap by 5 then 5 more db. Make sure > > to drop the cpe by the same amount. What you are trying to do is move the > > echo down so far that it can't be "heard". > > > > I've also had installs that are happiest about 2' above the ground! > > > > Here's a fun one for you. I've got one customer that shoots near a grain > > elevator. Most of the year he works fine, but near harvest, > every year, his > > performance goes out the window. It seems that the wheat in the > elevator is > > moved out and the empty elevator is worse than the full one. > > > > Out here we have VERY long links. I have one at 18 > miles. PTMP. Yet there > > are also customers within 1 mile. 10 to 15 mile links are common place. > > Multipath is a real head ache as the ground conditions change. Customer's > > service will be perfect, until it snows. Or until they harvest a field, or > > the ground dries out, or it rains etc. > > > > Fortunately MOST of the time this isn't an issue. But when it does hit ya, > > it can be very hard to figure out. > > > > One other thing you might want to try with your customer, turn the radio to > > the wrong polarity. You are very close to the tower so you should still > > have enough signal. I've not had to do this very often, but it's a little > > trick that has worked before. I've also pointed them 180* the > wrong way and > > had that work very well, especially with a grid. > > > > Let us know if anything helps. > > marlon > > > > ----- Original Message ----- > > From: "Steve Barnes" <st...@pcswin.com> > > To: "WISPA General List" <wireless@wispa.org> > > Sent: Friday, October 16, 2009 7:07 AM > > Subject: Re: [WISPA] New install driving me crazy.... > > > > > >> Marlon, DO you have or know of a good white paper on Multipath issues? I > >> agree with your assessment but I have several locations that I have not > >> been able to resolve Multipath for. I had an installation last week 3 > >> miles from tower AP. Clear line of site other than going over the > >> Neighbors Metal barn and between 4 metal grain bins. We could get a -69 On > >> 50% of the property but retries were 98% No matter where we tried High-Low > >> left right. 100 yards either way on the road and <10% retries and a -65 > >> signal. I just need to some documentation to solidify my understanding. > >> > >> Steve Barnes > >> Manager > >> PCS-WIN > >> RC-WiFi Wireless Internet Service > >> > >> Character cannot be developed in ease and quiet. Only through experience > >> of trial and suffering can the soul be strengthened, vision cleared, > >> ambition inspired, and success achieved. > >> - Helen Keller > >> > >> -----Original Message----- > >> From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On > >> Behalf Of Marlon K. Schafer > >> Sent: Friday, October 16, 2009 9:45 AM > >> To: WISPA General List > >> Subject: Re: [WISPA] New install driving me crazy.... > >> > >> Is that a bigger or smaller antenna size than what you have now? > >> > >> If you moved up by 10' and increased your signal levels, what 1000% or so, > >> I'd REALLY say that this is looking like a multipath issue. > >> > >> Often with multipath I've seen the signals hold well but performance suck. > >> It'll sometimes kill the signal though. > >> > >> I had one install that has some power lines in the way. Fought > >> intermittent > >> outages etc. for over a year. His signal was OK, but not great. Finally > >> something changes a bit and his signal dropped too low. > >> > >> Hmmm, bad radio. So I pulled his radio out and put in a brand new one, > >> still crappy signal. > >> > >> Double hmmmmm > >> > >> I put the old radio back in, left it off the mount and moved it around to > >> see what would happen. (I always leave 6 to 10' of cable on the mount > >> just > >> for things like this.) > >> > >> Triple hmmmmm > >> > >> Move the radio to the west 6' and DOWN 2' and he's got great signal, > >> faster > >> speeds than ever and is happy as a clam. Now one of my biggest PITA > >> customers just never calls anymore. It was a very amazing transformation > >> to > >> his service. > >> > >> Again, there were some powerlines *close* to the path but not in it. > >> Things > >> actually looked pretty good to me. But not to the radio. > >> > >> Your symptoms look like multipath to me. We don't see it's effect very > >> often, the systems handle it quite well today. But when it hits it can > >> hit > >> hard. > >> > >> laters, > >> marlon > >> > >> ----- Original Message ----- > >> From: "Mark McElvy" <mmce...@accubak.com> > >> To: "WISPA General List" <wireless@wispa.org> > >> Sent: Friday, October 16, 2009 4:50 AM > >> Subject: Re: [WISPA] New install driving me crazy.... > >> > >> > >>> Well before moving to the current setup, I originally had a CPQ-19, 10 > >>> ft lower. It had a -80 with the same result and I was seeing a lot of > >>> retries. > >>> > >>> -----Original Message----- > >>> From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On > >>> Behalf Of Marlon K. Schafer > >>> Sent: Thursday, October 15, 2009 9:30 PM > >>> To: WISPA General List > >>> Subject: Re: [WISPA] New install driving me crazy.... > >>> > >>> Change from b to g or g to be mode. > >>> > >>> Turn your power WAY down. That's way too hot of a signal. > >>> > >>> Any metal, trees, houses, power lines etc. anywhere near the signal > >>> path? > >>> > >>> This looks a LOT like multipath. > >>> marlon > >>> > >>> ----- Original Message ----- > >>> From: "Mark McElvy" <mmce...@accubak.com> > >>> To: "WISPA General List" <wireless@wispa.org> > >>> Sent: Thursday, October 15, 2009 2:30 PM > >>> Subject: [WISPA] New install driving me crazy.... > >>> > >>> > >>>> Installing a new customer, Tranzeo CPQ-19 to a MT AP, -60 signal > >>> up/dn, > >>>> -102 noise. About half the time I don't get name resolution and can't > >>>> browse pages. This happens with two different radios. It is kind of > >>>> acting like I am loosing routing or something. I also notice I will > >>> get > >>>> very high ping times sporadically along with drop pings. Best of my > >>>> knowledge no one else having issue on this AP, about a dozen users. > >>>> > >>>> > >>>> > >>>> Mark McElvy > >>>> AccuBak Data Systems, Inc. > >>>> > >>>> > >>>> > >>>> > >>>> > >>>> > >>>> > >>>> > >>> ------------------------------------------------------------------------ > >>> -------- > >>>> 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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