We've actually seen quite a bit of multipath this year. Probably 3 or 4 sites had to have the antennas moved. Several others aren't working as well as they used to, but we've got no where to move the antennas to.
It's a hard problem to diagnose. We had one customer that's been with us for a couple of years now. He always had somewhat slow, but usable, speeds. Finally things really got bad. I noticed his signal levels was WAY below what it should have been. Ahh, I've seen the Tranzeo cpq radios go deaf before so I put in a new radio. It was better but not right. Hmmmmmm. I then unmounted the radio and tried moving it around a bit. (He shoots over the road and under some BIG high voltage lines.) We ended up moving his antenna down 2 or 3 feet and over by about 6'. His signal levels went WAY up and his speeds more than doubled. The best part of all? He's not called me since that day! In the real world we can't always avoid multipath. We can only minimize it. When things just don't seem right on a link, it's one of the things I check for. Oh yeah, out here, in the rolling hills it hits us worse in the spring. Somewhat in the fall, but mostly in the spring. I *think* it's got to do with how the weeds etc. deflect the signals. Either that or just the water levels in our normally bone dry dirt. (I'm in desert country) I've always wanted to get one of those Berkley Varitronics units that shows multipath. Too bad they are so blasted expensive. laters, marlon ----- Original Message ----- From: "RickG" <[email protected]> To: "WISPA General List" <[email protected]> Sent: Sunday, April 26, 2009 7:32 AM Subject: Re: [WISPA] SOLVED - Signal Strengths I'm not saying this is your issue but I wanted to put this out on the list. I've heard and perhaps seen areas that have a lot of metalic content in the ground which causes reflection. Thoughts anyone? -RickG On Sun, Apr 26, 2009 at 12:10 AM, Jason Wallace <[email protected]> wrote: > Well, > > There was only a desert floor of dirt between me and the AP about 4 > miles away. Not even any houses to speak of. There were no metal roofs > directly in the way. There WAS a very large steel building perpendicular > to > me about 40 feet away. Also, within 2 miles, there's grain silos scattered > around that could cause a reflection. It was either this or it was right > at > the edge of Fresnel effects. > > SOLUTION? > > I changed to a CPE with a higher gain (Deliberating 15dbi). I think the > tighter antenna pattern acted like "blinders" to the out of phase signals. > I did not have to move the installation point. 70's db. All is well. > > Thanks everyone, for your encouraging input. > > Jason > > PS. I'm keeping an eye on it... > > Josh Luthman wrote: > > This happens a lot with metal roofs in the way. 10 feet over, around > the mentioned building we go from -90 to -65 > > On 4/25/09, Jack Unger <[email protected]> wrote: > > > You're seeing normal RF behavior. Simply mount the antenna where the > signal is the strongest then use your network monitoring system to keep > an "eye" on it. > > Jason Wallace wrote: > > > Everyone, > > I had trouble during an install today regarding signal strengths. > 2.4Ghz CPE in a location that should be no problem. Moving the CPE two > feet in any direction from the point where the CPE was installed > increased the signal by around 20db (-90 to -70!) > > Any idea of what phenomenon I am dealing with? > > Anything I should consider as I correct this install? > > Jason > > > -------------------------------------------------------------------------------- > WISPA Wants You! 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