Hi Everyone,
I have an opportunity to put up a cluster of 2.4 and 5gig ePMP APs on a cell tower, but the mounting location is just a few feet above the AT&T cell cluster. Obviously I'm going to be using shielded CAT5 and lots of grounding. I'm using fiber optic up to the tower along with copper for power. Will this work or will the cell RF get into everything? Does anyone have any experience with this?
Thanks,
Ryan
Im renting from American Tower. On this tower is ATT, Verizon and Clearwire(sprint). We are maybe 50-75 feet above all of them using Cat5e to our AP's on 3.65. No issues
I know personally I've had experience with cellular carriers interfering with Cambiums built in GPS sync in the ePMP line. I've been recommended to use a CMM to correct this issue.
Hi Ryan,
The Cellular cluster can interfere the GPS signal and using the CMM 3/CMM4, will help to avoid interference.
Regards,
Suman
Have to make sure the GPS unit is farther than 6 feet from other units minimum. Per documents ive recently read on the pmp450. This could be a problem due to how tower companies cram operators into cell sites.
Also, if your only a few feet above them, you may want to get some longer than normal boom arms so your not trying to shoot a signal through them, move the antennas outwards so your not hitting them. We Colo with att and Sprint a lot no issues, I’ve heard of issues around Verizon.
Thanks for all the useful info. I hadn't been worrying about the GPS at all. That changes my entire setup. I had hoped to use the new Ubiquity POE router at the top of the tower with only fiber and power running the 300ft. from the ground from another similar router. But I won't be able to use a CMM in this configuration. My only option is 8 CAT5 lines from the bottom of the tower, then? Hmmm. I'll have to think about this.
Regarding boom arms, I'm trying to get information about how far out from the tower the cell antennas are mounted so I can extend enough to get past them.
@rpmiller wrote:Thanks for all the useful info. I hadn't been worrying about the GPS at all. That changes my entire setup. I had hoped to use the new Ubiquity POE router at the top of the tower with only fiber and power running the 300ft. from the ground from another similar router. But I won't be able to use a CMM in this configuration. My only option is 8 CAT5 lines from the bottom of the tower, then? Hmmm. I'll have to think about this.
Regarding boom arms, I'm trying to get information about how far out from the tower the cell antennas are mounted so I can extend enough to get past them.
its fine to run Cat5 that far, don't break 328'
the epmp 1000 APs can use 48v power which won't have enough voltage drop to worry about. be sure to use GOOD quality shielded cat5e to avoid problems. GROUND GROUND GROUND everything, take a good look at how the cell company's ground there equipment, the ground run is always the shortest, and most conductive contacts everywhere. i'm sure the UBNT top router thing is decent device, but I'll refuse to use them for one reason, no ground lug.
if you deviced to go DC, don't forget surge protection on your DC lines.
netonix has a good top switch solution if you don't want to run so many cables, ( 6 mini) and can be powered by there other switches, we've got a few sites past 300' and we used 2 minis to break the runs and ground again as well as finish the last 60' to the antennas. you can run 5 EPMP radios from 1 6mini.
we've also sent 120VAC up to a small top cabinet in the past, it worked fine. used a 2nd cabinet on the ground for the battery backup and a fiber converter to access the gear from the ground.
with the arms becareful not to go out past them with the arms, just match there distance, or match it enough they are no longer a possible obstruction for you. if you go out to far they could scream interference from your physical location.
if you've got to use say 6' arms you might want to consider using LMR jumpers to keep your radios them selves tight to the tower for easy maintainance and send only the antennas out.
Thanks Chris_Bay,
If I can't use the GPS built into the ePMP 1000 radios, I don't think I can use a tower-mount switch because the CMM sync won't go thru it, so I'll have to run individual cables from whereever the CMM is, most likely the bottom of the tower. Correct me if I'm wrong about the CMM. I've only done small deployments with PMP100 and I used PacketFlux for sync thru the timing port. For ePMP, I've only used the built-in sync. They have no timing port.
And not to defend Upbiqui, but they doc says the EP-S16 switch has a ground lug (they call it a bonding point).
Ryan
Yes, the edgpoint units have grounding lugs. The lug on the 6 port edgepoint router is tiny though.
My mistake with the edge port, I couldn’t find it in the documentation when I first reviewed them. I looked hard as that seems like a cool product.
Ryan,
The epmp can take sync via power. Packet flux has a poe timing injector that should work with the epmp also, but I’d choose the cmm unless your dead set on using a specific switch. The top side timing port setup is pretty nice, we’ve used those a lot with our old pmp100 gear.
I've got no problem with the CMM, but using it means I can't use a switch at the top of the tower. Remember I'm very close to the cell antennas and the responses I've gotten to this post indicate the GPS will not work. Now I'm assuming that means ANY GPS in close proximity to the cell antennas won't work, not just the built-in ePMP GPS. Maybe that's not true?
Ryan
Packetflux Gig SyncInjector. You put in 24-48v and it puts out sync+power. You use a switch/router. Way cheaper and fits on a tower easier.
We have a small/medium NEMA enclosure on the top next to AT&T and Sprint with 4 backhauls and 8 APs.
So it's only the built-in ePMP GPS that has issues with cell interference. Cambium - any chance for a fix to this? We're paying for all these GPS receivers after all.
Wait, this injects the sync, but you need the sync pipe to produce it, correct? So where's your sync pipe GPS? Is it near the cell antennas or at the base of the tower?
Ryan