Poppycock! Here's the root of the problem.
All of the WiFi devices that I know of handle the authentication and admin functions at the 1 meg level. Maybe g handles it at 6 meg but it's still the *most sensitive* level. Most multipath is knife edge. The signal bounces off of a wire, the peak of a roof, the corner of a metal building etc. That signal is usually about 30dB less than the main signal. So, what happens when you have a -60 signal with a -90 echo (multipath for audio) into a device that has a receive sensitivity of -96? According to Ubiquity the NS2 has a 54 meg receive sensitivity of -74. It's 6 meg is -94 and it's 1 meg is an amazing -97! So really, anything over a -67 signal level opens the door to a lot of multipath for a lot of things that go on. Want to test this theory? Turn the power DOWN on the ap and cpe. Drop it to -70 or so on both ends and see what the performance does. I just installed a link to day. -82 signal (to one of my WORST ap's), 15ish mile link. The customer got 3 megs down and 3 up. A better signal would have certainly helped, but -60 wouldn't make up for the distance that much. What a -60 at the cpe would have indicated is that my ap's will be much more likely to interfere with each other. Every time I think I know what the geography around here is like I find another situation where my ap's see each other where I thought it totally impossible. Just yesterday I picked up a system that's got 17db into an 8db omni. The recieving system was a MT with an xr2 and 8dB omni. The two systems were over 20 MILES apart, probably closer to 30, I've not run the numbers yet. If the signal levels were too high I'd be my own worst source of interference on these two systems! The idea that "too much is never enough" only works well for hotrods and bombs. laters, marlon ----- Original Message ----- From: Travis Johnson To: WISPA General List Sent: Thursday, October 15, 2009 9:11 PM Subject: Re: [WISPA] New install driving me crazy.... Marlon, Since when is a -60 too hot of a signal? If you look at the spec sheets for testing on most of the wireless cards, you will see that -60 is their "ideal" signal. Travis Microserv Marlon K. Schafer wrote: 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! 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! 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! 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/
