Lightning Damage Sync Question

My tower had a lightning strike the other morning. All three of my 900 APs were damaged and my CMM now is saying “BAD - Under Current” under Sync status for antenna connection. Before this everything was running fine. After replacing all the access points and the electric company installing a new transformer, everything on this tower is going crazy. Customers are losing connection constantly. The only thing that isn’t working right now is the sync from the CMM. The APs are at 906, 915 and 924. They’re all set to generate sync now. Can these APs be interfering with each other without the sync even though using the non-overlapping freqs?

You are having problems because the AP’s are not in sync. There is a new ver. of software for the CMM that I think will help with this situation. It allows the cmm to recieve sync from an AP and passes it to the other AP’s so they will be in sync. The problem with your CMM is the GPS antenna or the surge suppressor that should be inline, is bad. You can get a new antenna pretty easily and they should be less than 200 dolars. We are in South Florida and deal with a lot of lightning. I have seen this several times before.

I was almost positive that’s what it had to be. I did load the new firmware. The APs are 300’ from the CMM. I have a SyncPipe I could use to provide the sync to the CMM I guess. I’ve seen a few posts on doing that, but not sure it was given a yes it would work answer.

Also, I’d love to hear any grounding advice you have on the canopy system. You should be a grounding pro in Florida. Is it best to run each AP going to the CMM through a Canopy CAT5 surge suppressor?

We place 600ss Surge Suppressors on each AP. These are grounded using short runs of #6 copper wire. We use a lightning suppressor on the GPS antenna which is also grounded with #6 solid copper wire. The GPS antenna is no special GPS antenna, I have used a 35 dollar Maxrad antenna with no problems as a temporay solution. I am not familiar with the syncpipe and its atritributes. If you need more details on where you might find one of these antemmas let me know.

If you are timing over the sync port, and all of your sync cables run down to the base of the tower or somewhere easily accessable you can simply tie the pins 1 and 6 together on each units sync cable.

Then set one to generate sync and the others to recieve sync. This would make the cluster all synced together, but keep in mind any near by clusters on the same band will not be synced due to the lack of gps.

As for protection, there are a few protectors available. Transtector makes specific protectors for Motorola Canopy products. One protector covers CMM3’s, which protects POE+GPS, and if you are using the sync port, there is a different protector that protects it.

Of course, you could install all of the lightning protection in the world and without a high quality, low impedance, single-point ground system it won’t be worth anything and you will continue to have problems. So, make sure your grounding system is good. That means you have ground rods in the earth or some other suitable type of protection system, and everything connects to it.

Thanks for the responses. I replaced the CMM and now everything is working great. I did put the 600SS on all of the APs and BH going into the CMM.

your should check to make sure your grounding is correct… we were having problems with ground and ended up using chemical grounds to help out… your grounding should be as close to 0 ohms as possible…

you’ll never get 0 but we have finally gotten ours down to 3.2 2 years ago (thats our highest ohms rating) at all of our sites and have not had a problem with lightning since… you’ll needs to really check out your grounding or it will just happen again. 1 or 2 ground rods on a tower simply will not cut it. we have almost 100’ of 0GA copper underground attached to 16 8’ rods and 4 chemical grounds as well on all towers. and as i’m sure you know now… lightning = not fun

best of luck

Below five ohms is preferable.

This is also in accordance with Motorola R56.