Synchronising units without a CMM

I have heard you can only sync one unit to another when using a sync cable.
not 1 to many, as the impedance would do bad things to the unit generating the Sync signal.

Ideally I want 1 AP (not with a CMM) to sync another 5 units.

Is this possible?

and how would i best wire it up? i know I use pins 1 and 6, but how would i best wire it up between the units if this is possible.


I have never done 6, but 1 driving two others works fine. Just daisy chain the wiring berween all three using cat 5 cable

I have done with 1 SM and 3 APs and work fine just using phone terminal and cat-5 cable. If possible you could find RJ-11 hub it will be better

I imagine the same would apply when syncing up backhauls as well? We have a remote slave backhaul that we want to hook to a BH master located on the same tower without having to buy another CMM.

Couldn’t we just set the BH slave to generate its own sync and then daisy chain CAT 5 to the co-located BH master and set it to receive sync?

slave units can not have sync. they get it from their master over the air. you can make one backhaul go each direction from same tower and use the masters back to back. you will have to reverse the downlink percentage on one, but you can sync the masters together that way. we just twist the wires together inside the module cup/bottom cover and hook whatever units together we need to.

Interesting… since I have never done this before, how do we exactly wire up the two masters? Do we just give them a common connection through the RJ-11 port, or do we need to alter the pinouts of the RJ-11 before we do this? Also, when you say reverse the downlink, do we give it the same percentage of downlink that it would normally have during the uplink?

I know these seem like very rudimentary questions, but since this will be our first try at this, I want to make sure I’m doing this correctly.

Thanks!! :slight_smile:

I don’t remember which pin is sync, I think it’s #1. #6 is ground. Just tie them together with the same pins on the other unit. One is set to generate sync and is a master. The other is set to receive sync through the sync port (RJ11) and is also a master. The master that is looking upstream toward the connectivity should be set to favor uplink since uplink is considedred to be going toward the master. if they are 50/50 it doesn’t matter. This works great until you have another BH on the third tower where you can’t help but have a master and a slave on the same site. We have done OK on 5.8 with 70-80 ft vertical separation with dishes, wide channel spacing and opposite directions unsynced. Haven’t tried less separation vertically because we didn’t need to, but my guess is that you could get by with a lot less. canopy says 100ft

Excellent! Thank you!