So I’m setting up our first 4 AP cluster. We have a license for 3.65Ghz.
We’re setting them at 7Mhz for bandwidth.
How exactly do I set all the APs? Are all the APs set for a center frequency of 3650000KHz?
What is the TX Power set too? It seems like the Admin and Config guide has conflicting numbers.
Also under Air Interface > Radio there are 2 Radio Index’s. What is this exactly?
Anyone? Bueller? Anyone?
When configuring your AP cluster, is your RF Plan ABAB or ABCD? You’ll have to keep the entire broadcast between 3650 - 3700 or depending on your area 3650 - 3675.
If you are configuring with 7 MHz bandwidth and ABAB, your RF Plan would be something like AP0 -> 3654000, AP1 -> 3662000, AP2 -> 3654000, AP3 -> 3662000. This is keeping 8 MHz Channel Separation and including a 1 MHz Guard Band. IF ABCD, you will still want to have at least 8 MHz Channel Separation between your sectors when using a 7 MHz channel bandwidth.
You also need to coordinate TX Power, DL/UL, Channel Bandwidth, GPS Sync between all your APs. Check out the “PMP 320 Minimizing Self-Interference in ABAB” document located on the Motorola Support website. http://motorola.wirelessbroadbandsupport.com/software/ Sector Downtilt also plays and important part when minmizing self-interference in ABAB configuration. Use a minimum of 3 DEG downtilt per sector, or use a downtilit calculator to determine the optimal values for your deployment.
If you are running in L2 Bridge Mode and using a CMM4, you will also want to make sure your EtherWan switch is updated to v1.91 software release and all the ethernet ports that your APs are connected to have Flow Control Disabled.
Your TX power on each AP for 7 MHz channel should not exceed 21 dBm. I have confirmed this with Industry Canada as the Admin Guide does not convey the correct numbers, but I haven’t confirmed with FCC and assume that the Admin Guide is correct.
The 2 radio indexes are because there are 2 transmitters in each AP (there are also 2 receivers). When configuring your frequency and TX power these will have to be the same for each for radio index.
Hope this helps!
This is exactly what I’ve been looking for thanks!
I’ve been considering doing ABCD, what downfalls would there be from doing this? It seems as if this would be the best way to minimize self-interference.
I can’t really see any downfalls either, except you would be using more of the spectrum that you may need to. If you are planning other tower deployments etc., channel reuse may be a factor you might have to consider.
Are you located in the US or Canada? I don’t believe the PMP 320 has been FCC approved for the upper 25 MHz, and in Canada you must be servicing a “Low Populated” Tier 4 service area to be able to use the upper 25 MHz. You won’t be able to setup your cluster to use ABCD if you are limited to only the lower 25 MHz as there are only 3 useable channels when using 7 MHz bandwidth. You would then have to configure your cluster as ABAB or change to 5 MHz Bandwidth.
Our license has us at 3650-3700Mhz. That would be enough to run ABCD right?
Sorry, I am in the US and was planning on doing 7Mhz channels.
You many want to check with the FCC on the upper 25 MHz as I don’t believe it is available for use. Otherwise you will have to deploy ABAB in 7 MHz.
When you say “upper 25Mhz”, are you referring to 3675-3670?
Yes, 3675 - 3700 MHz.
Thanks!
Once last question (hopefully). We’re trying to determine downtilt. We’re 260 feet in the area and the tower site is on a hill so we’re a good height above most of our potential customers. I figured a downtilt of 4.3° and hope to be able to cover a range of .3 miles out to possible 8 or 9 miles. Can I expect this?
Assuming you are using the Motorola Sector Antenna (PN: 85010090001) and you are 260 Feet AGL above customer… 4.3 DEG will give you a Inner Radius Distance = 0.36 Miles and a Outer Radius Distance = 3.53 Miles which would NOT appear to be Optimal. 3.5 DEG will give you a Inner Radius Distance of 0.4 Miles, Outer Radius Distance = Horizon which looks to be as close as you’re going get.
You can run your own downtilt calculation to see which would be best for your deployment. Check out:
http://www.terabeam.com/support/calculations/downtilt-cover.php
If using the Motorola antenna, Vertical Beamwidth is 7 DEG.
I was using 8° for the vertical beamwidth based on this document:
http://www.motorola.com/web/Business/Pr … _Sheet.pdf
Is this wrong?
Hmmm, I haven’t seen that one before. I was told that the Moto antenna was actually the PCTel SP3338-17XP65 which shows it as 7 DEG.
http://wildcard.pctel.com/2008_pctel_003/artifacts/SP333817XP65_SP333816XP90.pdf
Wonderful, conflicting data. 