Marlon, nice stuff. I agree with all that. My confusion comes from why I cant have a high gain antenna with the same pattern as a lower gain unit? Both should be able to be designed the same. -RickG
On Mon, Feb 23, 2009 at 1:13 AM, Marlon K. Schafer <o...@odessaoffice.com>wrote: > Vertical radiation pattern. > > Read this for a better description: > > http://www.odessaoffice.com/wireless/antenna/how_to_pick_the_right_antenna.htm > > Look closely at the very first antenna pattern. > http://www.odessaoffice.com/wireless/antenna/15_omni.jpg See how much of > the energy goes UP instead of down. And if you look closely you'll see > that > the main lobe goes up instead of straight out, or, more importantly, down > toward the customers. > > I buy the 8 dB Maxrad omni antennas with electrical downtilt these days. > Almost always 4* of downtilt, but sometimes I'll go as high as 12*. > > If you drop from a 15 dB to a 12 you'll DOUBLE your vertical coverage zone. > Or very close to it. > > That 15 dB omni you have probably has a 2 to 5* vertical pattern. An 8 dB > will have closer to 12 or 15 (I don't remember exact numbers off the top of > my head). > > In a nutshell, gain comes only from the focusing of energy. You can only > get that in two plains. Horizontal and vertical. Everyone looks at two > numbers, horizontal (omni, 120*, 180*, 90* sector etc.) and gain (15dB, > 12dB, 6dB, 24dB etc.). For the customer side the horizontal pattern > doesn't > mean much because you'll point the antenna straight at the tower's antenna > anyway. At the tower though, you need to cover MUCH more area, both from > side to side AND up and down. > > That help? > marlon > > > ----- Original Message ----- > From: "RickG" <rgunder...@gmail.com> > To: "WISPA General List" <wireless@wispa.org> > Sent: Sunday, February 22, 2009 9:23 PM > Subject: Re: [WISPA] tower issue > > > > Marlon, > > > > I was thinking about what you said about high gain omni antennas sending > > more signal UP. With respect to direction, what's the difference between > > between a high gain unit and a lower gain unit? > > > > -RickG > > > > On Sun, Feb 22, 2009 at 10:34 PM, Marlon K. Schafer > > <o...@odessaoffice.com>wrote: > > > >> Not sure if it's related or not, but high gain omni antennas are usually > >> a > >> great big no no. They tend to send more signal UP than in the direction > >> of > >> the customers. > >> > >> I'd replace it with an 8 or 9 db unit just on principal. You'll > probably > >> find that most customers will actually get a BETTER signal. > >> > >> laters, > >> marlon > >> > >> ----- Original Message ----- > >> From: "RickG" <rgunder...@gmail.com> > >> To: "WISPA General List" <wireless@wispa.org> > >> Sent: Sunday, February 22, 2009 7:23 PM > >> Subject: [WISPA] tower issue > >> > >> > >> > OK, here a good one! (aka, how I spent my weekend in a blizzard!) > >> > > >> > One of my towers has a single WARP/StarOS connected to a 5GHz grid for > >> > backhaul and a 15dBi omni for the local connections. > >> > On Saturday, after making some small changes, I rebooted it and it > >> > would > >> > not > >> > allow me to connect via wireless any longer - or my customers :( > >> > So, I go to the tower, connect up via ethernet and everything is a > >> > usual > >> > but > >> > I see all associations but only a few client have ip addresses. I can > >> ping > >> > the few clients but the packet loss is huge 80-90%. I then reload my > >> > backup > >> > but still get the same thing. I try changing channels, but still the > >> same. > >> > I > >> > then systematically begin replacing parts starting with the radio > card. > >> > Eventually, I replaced EVERYTHING but still have the problem. One > note: > >> > occasionally, twice of maybe three times, after a reboot, all came > back > >> > normal. The third time, I left well enough alone for now but of > course, > >> > you > >> > know what will happen the next time I reboot. > >> > > >> > Any ideas??? > >> > > >> > -RickG > >> > > >> > > >> > > >> > -------------------------------------------------------------------------------- > >> > 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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