Re: [smartBridges] Omni antenna coverage

[Derek Breiland]

Title: Message

Correct me if I am wrong but I beleieve that a splitter cuts the level of both of your antennas in half.   More coverage in degrees - less power. From: Rob Cleminson To: [EMAIL PROTECTED] Sent: Saturday, November 01, 2003 11:23 AM Subject: RE: [smartBridges] Omni antenna coverage Well, today I have been back up my tower and tried a lower gain Omni (8.5dbi) this gave a better signal to my clients close to the tower but the client further away had a worse signal � I am beginning to understand how my omni�s are pushing out their signal and I am now of the opinion that I must use sectored antenna�s.   I now plan to buy a 2 way splitter and install a 90 degree sector with the Omni � I shall point the sector antenna at my weakest clients and leave the omni up for the others � As I get more clients and more money I will replace them both for 2 x 180 degree sectored.   Thanks   Rob     -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Brian Winter Sent: 01 November 2003 08:19 To: [EMAIL PROTECTED] Subject: Re: [smartBridges] Omni antenna coverage   But surely the 24dBi is a pretty pointless metric, isn't it ?  Whilst I suppose its true that the gain of your aerial system might be 24dB greater than an isotropic radiator (perhaps - see later), if you're calculating the path profile to a client associated with this tower then the antenna gain is 12dBi at best, and thats usually the only reason you need to know about antenna gain.   The 24dBi is very questionable though.  If you are driving both antennas from the same RF source, you will have had to use a aerial harness of some kind (ie properly phased splitter/combiner).  At best you will get 3dB loss from this (maybe 6dB - long time since I did this stuff in detail).  If you have 2 seperate RF sources, then you simply have 2 seperate systems each with an aerial gain of 12dBi - which sounds like a much better idea for lots of reasons.   If you tilt an omni, as you observe, service on one side will degrade (except perhaps for aircraft :) ), but you will probably also lose service to distant clients on the "good side".  You might achieve the same, or better, result on the "good side" by bringing the whole lot 100' down the tower and removing the tilt to restore a circular pattern, thus recovering some coverage on the "bad side" too.  So much depends on the terrain you have to work with and the location of your clients - but I would agree with Rudolph that sectors would give you much more control in both the H and E plane.   bw ----- Original Message ----- From: Rudolph Worrell To: [EMAIL PROTECTED] Sent: Friday, October 31, 2003 10:48 PM Subject: RE: [smartBridges] Omni antenna coverage   Yes! 2 190 degree sector gives you 380 overlapping coverage.  12dbi on one side and 12dbi on the other = 24dBi overall.   You can always tilt an antenna to create a down tilt.  With an omni you would lose coverage on the side you tilt away from. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]On Behalf Of Jason Baugher Sent: Friday, October 31, 2003 5:35 PM To: [EMAIL PROTECTED] Subject: RE: [smartBridges] Omni antenna coverage 2 180 deg 12dBi sectors combine to make 24dBi in 360 deg? Mechanical downtilt on an omni?   Maybe my brain is just fried, but something doesn't add up here.     Jason Baugher -----Original Message----- From: Rudolph Worrell [mailto:[EMAIL PROTECTED] Sent: Friday, October 31, 2003 4:26 PM To: [EMAIL PROTECTED] Subject: RE: [smartBridges] Omni antenna coverage I only use Omni's at repeater sites with low number of clients.  I use 190 degree sectors for all serious connections.  12dbi in 180 or 12dbi in 360.  Well I chose  the 12 dbi in 180 each therefore giving me 24 dbi coverage for 360 degrees.   On your Omnis you should get them with a 3 degree elec downtilt or use a mechanical downtilt.  Electrical is better! -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]On Behalf Of Rob Cleminson Sent: Friday, October 31, 2003 5:13 PM To: [EMAIL PROTECTED] Subject: RE: [smartBridges] Omni antenna coverage I too am running with a 12dbi Omni at about 150�  - customers at about 2-4km get a good signal but the closer you get the worse the signal gets � I am about to swap out and try a 9dbi Omni to see if the RF pattern improves for the clients that are closer. Failing this I will chuck the omni�s and use sectored antenna�s   Rob     -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Ian Ellison Sent: 31 October 2003 14:57 To: [EMAIL PROTECTED] Subject: Re: [smartBridges] Omni antenna coverage   I am currently running airPointPro Outdoor units with Comet GP24-3 Omni's, which is a 12 db antenna.  I am servicing customers as far as 5 miles away with sufficient results.  However, the equipment is about 150' above ground level which im sure helps.  Good luck. Ian Derek Breiland wrote: Up to this point I have been running off of one tower with 3 sectors.  I am looking at putting an addtional AP up about 6 miles from this tower to penetrate into a community of homes that will otherwise be difficult to cover due to the number of obstructions not to mention their elevation on the map leaves a little to be desired.  It will also enable me to install a less expensive CPE at the customer site if I can bring the AP closer to the customer making the service a bit of an easier sell.   I want to utilize an omni antenna in this area.  I have not yet decided what to backhaul with yet but I am considering an APPO to the new XO2 at the remote.  I can use one radio on the XO2 for the backhaul on one channel and the other radio for the access to the customers.  I am not a big fan of repeaters unless absolutley necessary.  It seems that most complaints on this site have the word "repeater" in the paragraph so I will try and stay away from it.   My question is to anyone currently working with onmi antennes on an AP.  What ranges can I expect for the various dB omni antennas?  9dB seems small to me, 12dB is maybe the ticket, 15db - way overkill?  I do not want the pattern to get too large to cause problems with my main tower.  I am looking at trying to get out no more than 3 miles for the AP.  The AP and omni will be mounted on a 40'-50' existing tower.  Also has anyone had better results with one manufacturer over the other with the same dB antenna?   Any suggestions are greatly appreciated.  I will be doing more and more of this so I would like to get it right the first time based on others experiences in already doing it.