We use dual-pol antennas for our Orthogon links, which use the different polarizations for spatial multiplexing. This allows the Orthogon to provide higher throughput with less spectrum usage.

-Matt

Paul Hendry wrote:

Hi Tom,

        Our tower rentals are all based on wind-loading so a dual-pol
antenna costs the same as a single pol. What are the advantages of using
both polarities for the same signal in a good LOS environment?

-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Tom DeReggi
Sent: 17 January 2006 18:08
To: WISPA General List
Subject: Re: [WISPA] Multiple Radios on Single antenna

I'm not saying there isn;t a benefit now and then sharing a Dual pol antenna

between two freqs, otherwise nobody would make them. BUt....

We have found most tower agreements also, have restrictions in the agreement

that disallow using multiple radios our spectrum ranges on the antennas without paying for that as a second antenna, even though taking up only one antenna position.

We found that its just as easy to sneak/put up a second antenna, without managers knowledge as it is to put up a dual freq antenna without them knowing. So normally you gotta pay regardless, if you do it honestly. It becomes an issue of wether you are honest about what you put up, versus sneaking up extra options without paying. Wether its spectrum or antennas is irrelevant. Most tower owners don't audit their sides regularly because its jsut to expensive and even if they do, the auditors often are over worked, and don't always check thouroughly what they are required to supposed to check. Most colocators also aren't short on antenna space, so they are really charging you based on the value you are receiving being there, not really the actually antenna space. Although special cases do apply such as with windload requirement of over weighted towers or towers like clock tower that have a limited number of window openings for the antennas.

I also find saving money isn't that much of a savings because the antenna makers then also charge more for the dual pol antennas to counter most of your planned savings.

However, saving on time, clearly is an option, with only one antenna to carry and bolt up. However you may run into issues, where the alignment of the antennas may need to be varied to get optimal signal based on wether you

are aligning for 5.8 or 2.4. So because we like to engineer for OPTIMAL signal, apposed to compromised mostly best signal, we prefer to use seperate

antennas.

As a disclaimer: We pay for all our colocated antennas at our cell sites, and we do that because we honor our tower relationships, and have negotiated

good terms, and do not want to abuse the trust they have in us, so we maintain good relations. I mention sneaking up antennas only because, every

once in a while, we may have sneaked up an antenna to do the inital testing (which often requires it left there for a few days), so that we can avoid the lengthly antenna request process and timely paper work until after we are certain that the link is doable and tested. We justify sneaking the antenna up, because not only are we saving us time, we also are saving the management a lot of time, preventing the need to do paperwork unnecessarilly, if we are unsuccessful in pulling off the link we engineered. I do not advise attempting to pull one over on Management companies. If the Management company does not care what spectrum gets used, and charging just for the antenna space, the more power to you for being smarter.

Tom DeReggi
RapidDSL & Wireless, Inc
IntAirNet- Fixed Wireless Broadband


----- Original Message ----- From: "Chadd Thompson" <[EMAIL PROTECTED]>
To: "WISPA General List" <wireless@wispa.org>
Sent: Tuesday, January 17, 2006 10:30 AM
Subject: RE: [WISPA] Multiple Radios on Single antenna


Who sells dual band antennas? That could save some money on tower space and
simplify some installations.

Thanks,
Chadd

-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Tom DeReggi
Sent: Tuesday, January 17, 2006 9:19 AM
To: WISPA General List
Subject: Re: [WISPA] Multiple Radios on Single antenna


.  However, I am aware of many successfuly
using 2.4 and 5.8 from the same antenna.


--
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.1.375 / Virus Database: 267.14.19/231 - Release Date: 1/16/2006

--
WISPA Wireless List: wireless@wispa.org

Subscribe/Unsubscribe:
http://lists.wispa.org/mailman/listinfo/wireless

Archives: http://lists.wispa.org/pipermail/wireless/


--
WISPA Wireless List: wireless@wispa.org

Subscribe/Unsubscribe:
http://lists.wispa.org/mailman/listinfo/wireless

Archives: http://lists.wispa.org/pipermail/wireless/

Reply via email to