interesting problem with 900mhz

I have a 900mhz AP that is giving me all sorts of problems right now. I have tried everything I can think of and I was wondering if any of you have resolved a similar problem.

Freq is 906mhz

The problem is the SMs disconnect every 30-45 seconds. It goes from 21 users down to 13 users. If i ping an SM with a public IP assigned to it, it shows the sm dropping off and then reconnecting.

When i run a spectrum test it shows 906-915 pretty heavily used. When I turn off the AP it shows nothing in that range.

So I would assume its not a interference issue.

I have tested other freqs as best as I can, I have another AP located near this one on 924.

We have elevated SMs, they have a great signal, but it doesn’t make a difference

I have also swapped out the AP.

This AP has been in this location for ~2 years with nothing changing.

I did upgrade from 8.2.2 to 9.0, that appears to be around when the problem was happening. I down graded to the previous AP and it continued to do the same thing. The new AP is 8.2.7 and does exactly the same thing.

Sounds like interference.

If you turn the AP into an SM, how does the spectrum look?

Are the 906 and 924 AP’s configured identically and have sync?

An AP can tolerate more noise with fewer subs. As you add subs, interference issues are magnified.

The two AP’s have everything the same besides IP and Freq.

When i run a spectrum test it barely sees the 924 AP, very little noise from 906-918

If I turn off the 906 AP (the one in question) and run a spectrum from my truck, that whole area is very quiet between 906-918.

From customers houses I get the exact same results. Spectrum shows strong 906-910ish when the AP is on, if I have a tech at the office disable the carrier freq. 906-918 gets real quiet.

The bandwidth thing was suggested to me so I took one sm that has a jitter - 1 and -53 dbm assigned it a color code of 1 and assigned the AP a color code of 1 (so only 1 sm was on the AP) (also the sm was configured for 512/256 at this point). It had the exact same results as when the AP has 21 subs on it.

vince wrote:

If I turn off the 906 AP (the one in question) and run a spectrum from my truck, that whole area is very quiet between 906-918.

may be pointless. interference can be unnoticeable at ground level from your truck or sm's. as the other users suggested turn the AP into the SM using the setting and run a spectrum analysis from the AP so you see exactly what it sees from its elevation. trust me, we ran into a similar problem this summer. couldnt really see any interference on the ground but 100-200" up where our ap's were we were getting blasted

My bad, I did do that as well. same results.

we have also seem similar results of random disonnects with good signal when theres bad sync, or the sync cable is going bad. try setting the AP to generate sync and see if it improves. if it does, redo however it gets sync

vlan1 you were right, it was a sync issue.

This was driving me crazy

Thank you,