In the cellular industry the antennas for this purpose are manufactured to be mounted upside down. Moisture and down tilt issues are dealt with in manufacturing.
Thank You, Brian Webster -----Original Message----- From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org]on Behalf Of Eje Gustafsson Sent: Wednesday, January 27, 2010 4:25 PM To: 'WISPA General List' Subject: Re: [WISPA] omni upside down Not much, probably if you need multiple omnis you would install sectors. But if you need antenna diversity and use omnis this is one of the easier way to do it since you just need one standoff bracket. However when doing need to be wary of downtilt antennas especially for the omni tilted down and ensure you have no weep holes or similar that now end up at the top of the antenna. But with directional antennas on the client it seems base station diversity is not any greater advantage. It's good for roaming mobile users (laptops, pda, cellphones) that might not have direct LOS to the base station. On Direct LOS there is no reason to use diversity unless you are doing a mimo setup using a 2 chain radio. / Eje -----Original Message----- From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On Behalf Of RickG Sent: Wednesday, January 27, 2010 3:07 PM To: WISPA General List Subject: Re: [WISPA] omni upside down Thanks! Is there any advantage for a WISP to do this? -RickG On Wed, Jan 27, 2010 at 4:02 PM, Eje Gustafsson <e...@wisp-router.com> wrote: > Those are more than likely cell phone sites that have those big whip > antennas going up and down (believe they are 800Mhz frequency range > systems) > My understanding it has one out of two reasons why they are built like > that. > Antenna diversion or increased base station density. > Have one not too far from me that has a crown with a total of 6 omni's. 3 > up > and 3 down, mounted on a triangular crown. Those omnis are massive and my > guess are they are at least 10-15 feet it's hard to tell because the access > road is blocked and I never walked down to get close enough to compare to > the tower leg joints. > > / Eje > > -----Original Message----- > From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On > Behalf Of RickG > Sent: Wednesday, January 27, 2010 2:55 PM > To: WISPA General List > Subject: [WISPA] omni upside down > > While traveling around, I've noticed a few towers with omnis mounted upside > down with a neighbor omni mounted right side up. Whats the purpose in this? > -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! 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/
