Con someone please explain Transmit Sync Input
Sync to Received Signal (Power Port)
Sync to Received Signal (Timing Port)
Generate Sync Signal
what do you typically set an AP to that is connected to a CMM w/GPS?
When you have a CMM you would sync to power port,
If you have an ap and back haul sending back to a tower with cmm it would be (2)
If you have 2 ap’s and a back haul sending back to a tower with cmm it would be (3) and the 2 ap’s would be using the J-12 connection so there wouldn’t be a timming issue
I think
When ever you have a CMM with a GPS and have your AP’s BH’s plugged in to the CMM,
use power port sync
If you dont have a CMM with GPS then you have two options,
1 generate your own sync, but you don’t really want to do that unless that is the only device on the tower/location, if you have 2 AP’s generating their own syn next to each other then teh their timing of when they send and receive will not be in sync with each other if they are independantly generate syncs, thus causing self interference. This is also the case with BH and AP co-locatied. Or and SM-AP at the same location.
In a situation with say 2 AP’s without a GPS, you can get one AP to generate a sync and then if you make a timing sync cable (see docs) and connect the two AP’s using the RJ11/12 connections, you set the second AP to recieve sync from timing port that way the second AP 's timing is controlled by the first AP, hence they will be in sync (although I have read the sync cable does not give you 100% syncronisation).
In the case of a BH, if you have a slave and an AP then you are a bit stuffed, because the slave takes its timing from the MASTER on the other side, so the sync cable is no good, that is why there is no timing option in slave BH (a BH slave operates similar to an SM as a Master is like an AP). You have two options, have GPS at both sides (this way all canopy RF equipment in Theory will be in sync with eachother around the world).
It doesn’t stiop here, once you have got one timing source, you need to make sure the uplink/downlink percentages are the same for equipment at each location other wise if you will have some sending and some recieveing.
e.g 2 AP in sycn, one 50% downlink the other 70% downlink. assume one frame to be 1 sec. First 5 secs both AP’s sending second 6 and 7 AP1 receiveing and AP2 still sending 8-9-10 both sending. Problem at second 6 and 7.
This is big problem when you have BH slaves at the co-location, that is why it is strongly adviced you use different bands.
Hope this clarifys something for you, chances are you got more questions now.
the power port seemed the logical choice, but when we called it in to Motorola, they told us to use the timing port. We have more rerigistrations than it seems we ought to. So perhaps we can try it this week. Any other experiences?
VJ is close but not quite.
If you are using a CMM2 it requires you to run a second cable to each module’s timing port. So you will have to set all units on a CMM2 to recieve at the timing port. Also when using a CMM2 you must plug a AP into port 1 for gps to propogate to all other units.
When using a CMMmicro you only run one cable to each unit. You set all these units to recieve timing from the power port.
when you have a BH slave and an ap you are not stuffed. You simply tie the two units timing ports together with the cable VJ specified and set the AP to recieve timing at the timing port.
example: We all know how spread out New Mexico is well most of my sites use CMM’s but i have a few that don’t. They are pretty remote no other canopy around. I have a CMM2 at my main distribution site generating sync for the site a 2.4 BHM set to recieve timing at the timing port. It feeds a 2.4 BHS 14 miles away. At that location i have 3 5.7 AP’s. The AP’s are set to recieve timing at the timing port. I built a spyder cable that ties all 3 ap’s and the bhs timing ports together. Not done yet. I have a 5.7 sm on one of those ap’s feeding a 900 AP 5 miles away so if you think about it the 900 sm’s are getting their timing from two tower sites away threw a BH slave and a SM.