Wouldn't it cost more to rent a lift truck than do an install?
----- Mike Hammett Intelligent Computing Solutions http://www.ics-il.com -------------------------------------------------- From: "Ryan Spott" <[email protected]> Sent: Tuesday, February 23, 2010 9:15 AM To: "WISPA General List" <[email protected]> Subject: Re: [WISPA] That black magic > Well, before he invests in an install, have him rent a lift truck or > something to see what he can see. > > I have a few links that have this type of knife edge defraction. I run > them > using 802.11 gear (Mtik/Tranzeo). When I allowed full on access to all the > speed I could provide, complaints came from these clients. When I > throttled > them down to256/768/1M connections.. the complaints stopped and things > were > more normalized to these clients. > > ryan > > On Tue, Feb 23, 2010 at 7:05 AM, Mike <[email protected]> wrote: > >> I have a bright beacon I can turn on at the top of this tower. On a >> clear >> night recently, I turned it on. Even a ways up a corn crib he could NOT >> see >> the light. I think the terrain data is accurate. The alphimax site, >> once >> you create the path lets you go into Google Earth and "see" the hill. >> This >> part of the world doesn't have high resolution imagery archived yet, but >> I >> CAN see the ridge when I follow along the path. >> >> -----Original Message----- >> From: [email protected] [mailto:[email protected]] On >> Behalf Of Josh Luthman >> Sent: Tuesday, February 23, 2010 9:01 AM >> To: WISPA General List >> Subject: Re: [WISPA] That black magic >> >> To begin with, are you sure there is a bump there? Could it be bad >> meter resolution? >> >> Josh Luthman >> Office: 937-552-2340 >> Direct: 937-552-2343 >> 1100 Wayne St >> Suite 1337 >> Troy, OH 45373 >> >> “Success is not final, failure is not fatal: it is the courage to >> continue that counts.” >> --- Winston Churchill >> >> >> >> On Tue, Feb 23, 2010 at 9:55 AM, Mike <[email protected]> wrote: >> > I need to do a reality check with those of you familiar with knife edge >> > diffraction as a propagation medium. First, I should paint the scene: >> > >> > >> > >> > I have a corporate farmer almost 16 miles away who is motivated. His >> > options are satellite, dialup he currently uses, or us. >> > >> > >> > >> > A spectrum sweep of the property found absolutely no 2.4 signals. By >> > in >> > large, these rural areas are very quiet. >> > >> > >> > >> > There are no trees or obstructions in the near field or out quite a >> > ways. >> > However, there is a ridge almost half way between us. I am embedding >> > an >> > image of the path here created with alphimax.com path estimator. >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > I have a test unit which is a 19 dB panel/radio with an AP fastened to >> the >> > back. It lets me hand hold a test unit and see what it sees on a >> > laptop. >> > Standing on the ground on his property we got an ALMOST usable signal >> > in >> a >> > short test. He has a 35 foot TV tower next to the house on which we >> would >> > install. >> > >> > >> > >> > Perhaps one would look at the path profile and common sense would >> > dictate >> it >> > won't work. However, I use knife edge diffraction successfully on a >> handful >> > of installs. Besides, black magic sometimes trumps common sense. >> > >> > >> > >> > I have never used this technique where the ridge is close to mid point. >> On >> > all others the ridge was closer to the user. All of them work except >> when >> > tropospheric ducting enters into the equation, with one exception. I >> have >> > told the users this is a 98% link and it WILL go down during those >> events. >> > Earlier this winter we had a few days of ducting which caused a couple >> > of >> > them to fade. I saw a 15 dB fade on those. Statistically, ducting >> should >> > only affect this area 20 some hours a year. >> > >> > >> > >> > The single exception was when the obstructing hill had soy beans >> > growing >> on >> > it. That particular one went down in late fall when the beans were >> > ready >> > for harvest. The previous 2 years the field had corn planted on it and >> had >> > absolutely no issues. I think dry beans affect the signal because they >> are >> > no longer "row" polarized and randomly scramble the signal beyond use. >> Once >> > the beans were harvested, the signal came back like usual. >> > >> > >> > >> > On this path in question, I found the ridge. There are no trees, >> > instead >> it >> > is farmed. There is corn stubble on it right now. >> > >> > >> > >> > I am curious what others have found in these NLOS situations. Because >> the >> > obstruction is mid path, will the signal still be there next fall as it >> is >> > now? Are mid path obstructions on a long path better than obstructions >> > closer to one end? Am I absolutely stupid for even considering this >> > install? >> > >> > >> > >> > I went over all the physics involved and told him of my experiences. >> Like >> I >> > said, he is motivated. I told him I wouldn't tie him into a contract, >> but >> > we'd go month by month and if we found later in the year it wasn't >> working, >> > we'd cut our losses. He was OK with that. >> > >> > >> > >> > Since I respect the viewpoints of many of you, bring it on! >> > >> > >> > >> > >> > >> > Friendly Regards, >> > >> > >> > >> > Mike >> > >> > >> > >> > Mike Gilchrist >> > >> > Disruptive Technologist >> > >> > Advanced Wireless Express >> > >> > P.O. Box 255 >> > >> > Toledo, IA 52342 >> > >> > Mike's >> > >> < >> http://www.tamatoledonews.com/page/category.detail/nav/5001/Local-Columns.h >> > tml> Weekly Column >> > >> > 239.770.6203 >> > >> > [email protected] >> > >> > >> > >> > >> > >> > >> > >> > >> > >> >> ---------------------------------------------------------------------------- >> ---- >> > 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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