Need Advice about PTP 650 GPS Sync

I am planning for a network where 4 PTP 650 will be at same tower. in that case I need to use GPS Sync. Now my question is do I need 4 unit  WB3665 and 4 units WB4141 or 4 unit  WB3665 and 1 unit WB4141. 

if I need 4 unit  WB3665 and 1 unit WB4141 then how can I share one antenna with 4 PTP-SYNC units?

Hi Monir,

there is a lot of information about this in the PTP 650 User Guide.  See page 2-46 and 3-31 of the 01-21 version of the user guide which is available on the support website.

Specific to your questions.  Yes, you will need one WB3665 per master and if GPS sync is required you will need just one WB4141.

You can daisy chain up to ten WB3665 off of one WB4141 GPS source.

To link clustered PTP-SYNC units, connect the SYNC OUT port of the first PTP-SYNC to the GPS/SYNC IN port of the second PTP-SYNC in the chain. Repeat for subsequent PTP-SYNC units in the chain.



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In relation to PTP Sync topic - what if the network is like this:

I have 13 PTP links in a single tower pointing in different directions. I understand the purpose of the sync, assuming we are limited to 10 Masters in a cluster, thus, I still have 3 Master remaining for the 2 cluster.

For this case, do I now needed to include 1 GPS receiver per cluster to make the network correctly configured? Or just create this clusters (10 & 3)  and assign 1 Master Cluster for each group, then allocate non-adjacent frequency (say, 5470 for Group10 and 5740 for Group3)?

Which will be the best configuration?

Thanks and regards,


Hi Gerry,

It makes sense to synchronize all of the links to the same reference. One way to achieve this is to split the ODUs into two groups, and to use one GPS receiver for each group. The groups could be split 10 and three, or more evenly, for example seven and six.

The PTP-SYNC buffers the 1 pulse-per-second signal from the GPS receiver, or from the PTP-SYNC neighbour in the chain. This introduces a small delay in each link in the chain. We have tested PTP 650 with a chain up to 10 PTP-SYNCs. However, the limit of 10 devices is somewhat arbitrary, and a chain of 13 PTP-SYNCs would most likely work correctly.

It's quite unusual to deploy 13 links at one tower. Just out of interest, how many different RF channels are you using?


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Hi Mark,

This is to be an actual project and is currently under design stage. Yes it would be composed of 13-PTP 650 links at a single tower. Maybe we would be able to cut this to 12 instead.

As stated and as you mentioned it is better to group them instead (10 and 3, and 7 and 6 and so on) associating 1 GPS receiver per group/cluster. Thank you for the clarification,  as this will be our first network integrated with PTP Sync and we do not want to fail this client.

For the channels, we are actually allowed to use 5740 - 5850 MHz, so I guess we can work this out fairly, plus following best practices for unsync PTP systems.