Still trying to get all of my ducks in a row so we can start deploying the ePMP1000 2.4Ghz sync AP's that we just received. I know best practice for frequency reuse is 4 90° sectors running ABAB configuration, which i want to do. BUT, due to cost, I may have to settle on 3 AP's instead of 4 on a lot of our towers. My questions are as follows:
1. How would I set these AP's up so that I get any GPS benefit from them, being 3 sectors and not 4?
2. Am I wasting my money by using Sync radios in a 3 sector cluster, or should I use un-sync radios?
3. Other than Cambium 2.4 sectors, do you recommend any other vendor antennas (mainly due to price) in the 2.4 band?
bang for the buck, the cambium sectors have it. they have a clean smooth signal pattern, which a poor pattern can cost you subs.
GPS sync is always good when having neighboring channels, without it you'll be dealing with co-band self interference. with it, that issue is clear. plus your towers in the distance can be synced with it still allowing signal re-use.
You want all 3 of your APs to start with a sync'ed connectorized radio. Use channels 1/6/11 and make sure all of them are using GPS sync (the antenna is included).
With 4 APs you can use frequency reuse which is channels 1/6/1/6 or 11/6/11/6 for example - this requires 4x 90* sectors. This means you have another 20 MHz channel to put your routers into, avoid interference, or if you end up having a lot of density you may be able to slap another AP up with that unused channel (two more if you do frequency reuse).
My ePMP1000 will be arriving today. Do I need just one sync radio or do they all need to be sync'd radios?
Hi. Just to maybe clear up the confusion - you 'CAN' choose to use any Cambium ePMP Radio as an AP or a SM. Every ePMP can be configured as either a SM or an AP or a PTP radio. That being said, if you choose to use a non-SYNC'd radio as an AP, you can't of course SYNC them. :) Everyone would recommend that you only use Sync'd AP's - the benefits of SYNCing are awesome.
Also - only the AP side of things need to be SYNC'd. The AP creates the 'schedule' for everything connected to them - so none of the SM's need to be SYNC'ed units. They will be synchronized to the AP they are connected to automatically. So - you WILL want to have GPS_SYNC units for your Access Points, but none of the SM's need to be.
Lastly - there is a subtle but important difference between SYNC'ing and FREQUENCY REUSE. Just for a weird example, if you decided to put two AP's with OMNI's on a tower, one at 50' and one at 100' on the same tower. You certainly would want those to be GPS SYNCd units, so that they would TX and RX on the same schedule. However, you couldn't really do any frequency reuse in this (weird) example. All your SM's would hear both Omni's about the same, and if you set both AP's on the same channel, there would be interference all over the place. However - if you put those two AP's on Channel 1 and Channel 11 - then the GPS SYNC will still get them TX/RX on the same schedule, and that willl dramatically reduce self interference between the two Omnis.
So - back to your question about 3 antennas.. You can't really ''re-use'' frequencies with three antennas, since the edge of one sector is going to overlap another sector, so if you set two (or three) of those sectors to use the same channel, some clients will hear both sectors about the same and interference will be a mess. BUT, you can put three antennas on channel 1, 6, and 11 and the GPS SYNCing will have them all TX/RX on the same schedule and that can dramatically reduce self interference between the Antenna. As long as you have GPS Sync'd AP's, then that'll ensure that one of your sectors won't be in RX mode trying to listen to some client 5 miles away right at the same instant that another sector is in TX mode 2 feet away and blasting at a -32. With Sync, that doesn't happen - they all Sync their TX/RX schedules.