GPS Sync - I'm tired

The problem is a Chinese satellite out of its orbital position. I understand that they are already interceding for the owner to correct the problems that are causing.

best regards

Same issues here. I've contacted support, and I get the same reply that's of no help. "Change your Antenna, go test GPS with your cell phone" When I have 10 APs on the same site, and I colocate their pucks in the same orinatation and we will see random loss of GPS across the sites and it will almost never auto recover. Requires a hard reboot of the AP. 

I have noticed our sites that are aginst a hill seem to be impacted the most, but it's never ALL aps at one site. It's only ever one at a time, and they don't recover typically need a hard reboot.


@matkix wrote:

Same issues here. I've contacted support, and I get the same reply that's of no help. "Change your Antenna, go test GPS with your cell phone" When I have 10 APs on the same site, and I colocate their pucks in the same orinatation and we will see random loss of GPS across the sites and it will almost never auto recover. Requires a hard reboot of the AP. 

I have noticed our sites that are aginst a hill seem to be impacted the most, but it's never ALL aps at one site. It's only ever one at a time, and they don't recover typically need a hard reboot.


We had am issue a long time ago simular to what you described, i actually traced it down to one specific AP causing interference to the rrst of our APs. Next time you loose sync,  hard power cycle the APs that ARE getting sync, wait 5 minutes between cycles to see when your def one starts getting sync.  If you can pin it down to one ap, replace that one.  I have no idea how or why that happens, but ive found that one time.  It progressively got quicker and quicker.    The issue the rest of the thread discribes is a interference issue related to being drown out from a carrier, or atleast thats what ive gathered from them. Fighting that problem now myself. 

Funny, I use PacketFlux's gigabit sync-injector, a sync box junior and believe it or not Ubiquity's Eth-SP at my tower sites and haven't lost a single radio, switch or timing unit yet. One tower gets struck so often that it should have melted by now. Burn marks on the top-rod show repeated strikes.  

Now the important question: have you heard of R-56 protection standards? We setup all our sites to this spec that exceeds CEC and the NEC specifications. It might be overkill but I say not loosing equipment is worth the extra investment of time and a small amount of extra protection equipment. Most of the important points simply come down to single grounding point interface, dont create a loop through earth, ground everything at the correct place and remember that a lightning bolt always takes all paths to ground and that the bolt you see may not be the direction of current flow! 


@Douglas Generous wrote:

Funny, I use PacketFlux's gigabit sync-injector, a sync box junior and believe it or not Ubiquity's Eth-SP at my tower sites and haven't lost a single radio, switch or timing unit yet. One tower gets struck so often that it should have melted by now. Burn marks on the top-rod show repeated strikes.  

Now the important question: have you heard of R-56 protection standards? We setup all our sites to this spec that exceeds CEC and the NEC specifications. It might be overkill but I say not loosing equipment is worth the extra investment of time and a small amount of extra protection equipment. Most of the important points simply come down to single grounding point interface, dont create a loop through earth, ground everything at the correct place and remember that a lightning bolt always takes all paths to ground and that the bolt you see may not be the direction of current flow! 


We ground properly.   Ive shared stories here and you can see some of our grounding work.  Our issue was most definitely linked to packet flux gear.  That being said that was mostly pmp100 and 320 gear. I have not used any of thier new gear for any length of time to determine if they have or have not fixed the issues we had with them.   None of thier old stuff had grounding lugs and 100% plastic housings.   I ordered 1 unit to test, and didnt deliver sync reliably to the epmp and 2 radios kept falling to 100 meg, but like i said we are pushing wire length.   Im unwilling to remove any of our LPU for long testing or operation as i stated above. 

I do not know the older equipment, but I do know that the latest revisions do work properly and the syncpipe 2.2 and the syncbox jr  (replaced the syncpipe) work very well with no timing drops. I have epmp1000 gear at 1gbps (force 200) working just fine beside older canopy 100mbps gear through the same syncinjector. I did notice that the epmp grea is more sensitive to cable type (cat5e-300 vs cat5e-350) and termination issues. On one tower we used 300Mhz spec cat5e and had nothing but troubles getting 1gbps to work, on another tower we used 350 spec cat5e and had no troubles at 98m long cables to the syncinjector with a 1m cable to the LPU and switch.

AP-------lpu--injector--switch

I would never tell someone to remove there LPU for more than a few seconds to test if it was bad. That is just stupid and not worth the dangers of blowing an expensive switch.

Is there any way to use some in line sync source and still run POE on a switch for the ePMP 1000 APs?

Mat

At this point in time, no.
Inline sync while using a poe switch to supply power is not possible. There are devices such as the CMM (cmm micro had a 10/100 switch built in) or PacketFlux sync injector that allow adding power and sync to different switches.

I think over integrating devices in one box is a bad policy to begin with. If the switcg dies in a multi box setup, you replace the switch and its back up. If its all in one box, you spend more money to toss the replaced unit for what could have been a mucg cheaper repair.
Dont get me wrong, replacing one big box over 3 small boxes is a nice notion, just that much harder to fix.


@Chris_Bay wrote:


We ground properly.   Ive shared stories here and you can see some of our grounding work.  Our issue was most definitely linked to packet flux gear.  That being said that was mostly pmp100 and 320 gear. I have not used any of thier new gear for any length of time to determine if they have or have not fixed the issues we had with them.   None of thier old stuff had grounding lugs and 100% plastic housings.   I ordered 1 unit to test, and didnt deliver sync reliably to the epmp and 2 radios kept falling to 100 meg, but like i said we are pushing wire length.   Im unwilling to remove any of our LPU for long testing or operation as i stated above. 


For what it's worth, the newest SyncInjector units we've gotten from PacketFlux support two power supplies, jumpers onboard to decide pinouts and which PS feeds each radio, and the power connector is 4-pin: DCneg, DCpos-A, DCpos-B, and shield, which is tied to the ethernet shield in the ports.

j

I am using the packeflux sync injectors and even with long cable runs I dont lose sync. One of our towers we have the syncbox jr up on the tower with 120ft of cat5e for the sync run back to the sync injector. Still never lose sync.
For LPUs we chose to use ubiquity Eth-SP.
These are fully gigabit friendly and we did a horizontal cable run between buildings for a client that is over spec by 3m (about 10ft) and still get gig speed links. I could not do this with other LPUs as they would fail anytime we got close to max cable length.

If you dont want to go packetflux then your looking to the CMM4 option. The other CMM units do not do gigabit.

We just had another ePMP radio just suddenly lost all sats for about 3 hours then come back up. Then about 2 hours later it lost them again.  It either sees 20 and tracks 16 or it sees none at all while the other radios on the tower (A mix of ePMP and Airfiber) work fine and show no decrease in number of visible sats, tracked sats or SNR.  

Already in the process of converting all the epmp on the tower to packetflux for sync. As for packetflux actually causing lightning strikes or lightning damage...  I will say that way back in the day when we first started and used the parasitic syncpipes we noticed a big decrease in lightning damaged a few years later when we changed over to the SyncInjectors but since then I don't believe we have lost a single piece of equipment that I could in any way attribute to the Packetflux gear (or anything else in the cabinet actually).  Though in all honesty using the parasitics put powered equipment at the top of the tower and changing over to the sync boxes put the all the sync equipment at the bottom of the tower so I would expect less lightning damage as a result.



we changed all of the round GPS pucks to the glonass square pucks.   SNRs look a hell of a lot better, i'll report back again tomorrow on how stable this stays.   

looks like our problem is solved with the different pucks,  this time of night of would have already had atleast 1 of the APs in holdoff and no sats tracked, all doing well.

cambium!!! PLEASE get these in the supply chain to be purchased seperately!     hopefully this will fix anyone else who runs into this when packet flux or cmm isn't the fix for them. 

Following up on my last post, my problem remains solved with all 4 2.4 APs on this tower.   my original problem occurred from interference after ATT upgraded their LTE gear on this same site.  since their upgrade we lost 2.4 sync constantly here, the 5ghz radios have not been bothered.     I changed our 2.4 APs on this site to the same pucks that are included with the 5ghz radios supporting glonass and it got rid of the interference problem.  the APs sometimes drop as low as 4 APs tracked, but only briefly and do not loose sync like they had for many hours at a time.   they are not hitting hold off timer at all now.  attached is a week worth of chart time, we changed the antennas Monday morning and close of business Thursday we still have yet to lose sync.   previously it was at least 1 of the 4 APs without sync every night, at least.    

Hopefully, these GPS antennas will be sold separately soon!

untitled.png

I'm still having a problem with ePMP 1000 losing GPS sync entirely on our tower. Sometimes a power reboot with the Netonix will fix it, sometimes now. I've had to resort to running in Flexible mode as it's not intermittent. When it's working properly, it's tracking 9 satellites no problem. Then randomly it'll drop to 0.

I'm on 3.5.1 on these AP's now.

Is there an explanation or fix Cambium?

Are you still usung the round gps puck? Or have you tried the square one? As others have pointed out, the filter on the gps antennas is fairly weak. Any source of interference will cause the gps reciever to become desensitized.
Also thing to note about the square ones, they must be virtical with the cable out the bottom. I have seen as much as 12dB in difference. If using the Cambium antenna, move your gps puck to the support pipe or tower leg. These antennas perform better with the large metal base as a ground plane reflector. That and not having the rf bleed from the sector antenna into the gps antenna will help keep the gps receiver from being desensitized.

We place the gps antennas on the down-tilt mounting bracket on the back of all but our south facing sectors. Those we mount on a steel muffler clamp on the support pipe just above the sector antenna. The magnet is there for a reason, use it.


Yes, we're using the round GPS pucks that came with the ePMP 1000.

They are facing the sky in the sense the cable is coming straight down out of the pick. I have a picture attached. 

1 Like

I would try the square glonass puck. The round ones just dont have the immunity to rf saturation. We mount ours inside the bracket between the studs from the antenna but that wont make a lick of difference.
Dont coil the gps cable inside the rf box nor use a zip-tie or the wire tie that comes with the gps antenna. Just let the cable be free inside the aluminum box. If you coil it or pinch the thin cable, then you could damage the cable and allow all of the rf bleed from the radio to enter the cable.

Btb, nice choice of antenna. We use kp as well and have been very satisfied.

I'm not sure where I can purchase the square GPS antenna separately?

At this time the ap-lites are a good source. Still waiting on replacement gps pucks to become available.
We use the ap-lites for ptp links and use packetflux sync-injectors for our timing but have the puck as a backup. If you go the packetflux method, make sure its the gigabit version and set the internal jumpers for 802.3at power scheme and good 350mhz or better cat5e/cat6 cables. No cheap CCA.

Give the ptp link the round gps antenna and use the square glonass antenna for the sector ap.