Sync Pulses received

Products PMP
1

Hi community,

We have a doubt, Which percentage of Sync pulses received is the minimum to ensure a stable sync? or what is the percentage where the AP loses Sync? 

we have an 2 AP in the same tower that the sync (received from a UGPS) has variation from 69% to 100 %. And Today one of them start to lose SMs.

Thank you 

Regards.

2
@FT wrote:

Hi community,

We have a doubt, Which percentage of Sync pulses received is the minimum to ensure a stable sync? or what is the percentage where the AP loses Sync? 

we have an 2 AP in the same tower that the sync (received from a UGPS) has variation from 69% to 100 %. And Today one of them start to lose SMs.

Thank you 

Regards.

Hi FT,

Just as a little background, the sync pulse % measures the average number of pulses received over the last 5 minutes with a rolling average. If you're seeing this number well below 100% often, it probably indicates either your sync source is having trouble maintaining sattelite tracking, or you may have an issue with cabling (length/shielding) that's causing difficulty for the radio to see pulses.

Ideally, this should be very close to or exactly 100% with a good sync source.  What kind of sync setup (hardware/cabling) are you using on that tower currently?

-Al

2 Likes
3

Thank you for your explanation, 

We are using one UGPS for these two Medusas with the 16.0.01 version, using normal phone wire for provide sync. We are going to check the UGPS (position in the tower and so on), wires....

4

No problem.

While you are doing that, I would make sure to read this thread, because it has some important information about UGPS with 2 APs. The thread refers to 450i, but 450m (Medusa) shares common hardware for the AUX port (which the UGPS plugs into), so the same information applies to 450m: https://community.cambiumnetworks.com/t5/PMP-450/ugps-power-and-sync-with-450i/td-p/71868

Pay special attention to the recommended hardware/cabling in the last post in that thread here: https://community.cambiumnetworks.com/t5/PMP-450/ugps-power-and-sync-with-450i/td-p/71868

For dual-450i or 450m use with UGPS, it is required that there is an auxilliary power source on the center input of the UGPS. There is a known issue with power droop when 2 450i or 450m APs are connected to the UGPS which can result in lost sync. Also, even with an auxilliary power source on the UGPS, you should still enabled the "UGPS Power" setting on both radios to ensure you can see sattelite info in the GUI.

If you're still having issues after following the recommendations above, feel free to get in touch with your RTM or with our support staff to help gather more information about your setup and we'll make sure to get it all working.

-Al

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5

Hello, 

Thank you so much for your information, 

I made what you told me ( I activate the option "Aux Port Power to UGPS" in both Medusas) the problem persist (I get 60% of sync pulses , so I spoke with the technician for go to the tower and check everything), the Weird thing is that even being the Aux Port Power to UGPS option enabled, I cannot get GPS Satellites information, I attach here what I can see in the sync status. 

Regards.

6

With the Aux Port Power to UGPS the satellite information should be appearing.  Is it possible the cable has an issue?   There are two pairs used, one is for sync pulse and the other for communications.

1 Like
7

Hello, 

yes, may be the wire could have an issue, the technician will go for check everything in the tower, 

I will provide the information after the technician go. 

Thank you for your information

Regards

1 Like
8
@FT wrote:

Hello, 

Thank you so much for your information, 

I made what you told me ( I activate the option "Aux Port Power to UGPS" in both Medusas) the problem persist (I get 60% of sync pulses , so I spoke with the technician for go to the tower and check everything), the Weird thing is that even being the Aux Port Power to UGPS option enabled, I cannot get GPS Satellites information, I attach here what I can see in the sync status. 

Regards.

You may have missed it in my original email, but I didn't see if you had mentioned anything about auxilliary power being connected on the center plug of the UGPS? I'm guessing it must have been if you didn't originally have UGPS power enabled on the 2 radios, but it's criticial to do so for a 2-450i/450m setup to ensure enough power.

I agree with Dave, you may have a cabling issue. It looks from the screenshots that both devices are at 60% sync pulses, which is more likely not a radio issue since it's happening on both at the same time, and would seem to indicate a cabling/UGPS issue, especially if GPS data is also not working.

-Al