Yabut, a dish "concentrates the forward radiation." So does a panel, a slot antenna, and many others. I just wondered why you thought a Yagi solved your problem. A 2.4G yagi has large diameter elements compared to wavelength, not like the old VHF Yagi's, but are prone to icing in the winter up north. What magic did you find in the Yagi? Just curious.
"Lucy, you got some 'splainin' to do!" Ricky Ricardo At 09:31 PM 10/18/2009, you wrote: >Because yagi antenna concentrates the forward radiation and response. -Lucy :) > >On Sun, Oct 18, 2009 at 9:48 PM, Mike <[email protected]> wrote: > > 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_note > 09186a008019f646.shtml > >>-RickG > >> > >>On Sun, Oct 18, 2009 at 10:51 AM, Marlon K. Schafer > >><[email protected]> 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" <[email protected]> > >> > To: "WISPA General List" <[email protected]> > >> > 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: [email protected] [mailto:[email protected]] 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" <[email protected]> > >> >> To: "WISPA General List" <[email protected]> > >> >> 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: [email protected] > [mailto:[email protected]] 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" <[email protected]> > >> >>> To: "WISPA General List" <[email protected]> > >> >>> 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: [email protected] > >> >>>> > >> >>>> Subscribe/Unsubscribe: > >> >>>> http://lists.wispa.org/mailman/listinfo/wireless > >> >>>> > >> >>>> Archives: http://lists.wispa.org/pipermail/wireless/ > >> >>> > >> >>> > >> >>> > >> >>> > ------------------------------------------------------------------------ > >> >>> -------- > >> >>> WISPA Wants You! 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