Power Levels

I’m not sure if I am having a problem, but I have about 3 or 4 customers now where the power levels recieved at the AP and SM are very diffrent. They are on 900Mhz Indoor Units and most of our indoor units the power is close to the same and I think it should be as we have a 9db Omni on the AP and the indoor is a 10db I believe. Both the AP and the SM are set to the same power level on the radio configuration. Here are my Three Examples


Cust 1:
.75 miles
AP Power Level: -81
SM Power Level: -73

Cust 2:
.36 Miles
AP Power Level: -79
SM Power Level: -64

Cust 3:
.47 miles
AP Power Level: -76
SM Power Level: -68

Given that I installed all these units, I feel that the alignment is decent. I don’t know what elese it could be, we have other indoor units and outdoor units that are right inline with each other where the AP is the same as the SM, including our 13 mile link.

Thanks,
Ben

We have noticed the same thing on some our units. The AP and SM power level do differ from each other slightly. we’ve noticed it even more on our 900mhz units. Usually when it gets pretty far off it mean your getting some interference on one side or another. But as long as link tests are good and no re-regs. the link should be stable.

Are these P10 SMs?

yes all our SM’s are P10 with 8.2.4 on them. the AP is actually a P9 with 8.2.4

Thanks,
Ben

If it was interferance which side of the link do you think it would be on since the AP is showing a worse power level.

Thanks,
Ben

If the ap shows a worse power level it usually on the ap side, but just to confirm i would shutdown the ap while you do spectrum on the sm side. Then do a spectrum on the ap side to see what the difference is.

thats strange that all of these are with in a mile. meybe try turning the power level down on the closest radio. we had an incident where one radio was so close and so loud that we were losing others around it

I will do some spectrum anaylsis and take a look. Since we are using an Omni it would seem odd that only certain customers would be affected by any interferance at the AP. I have turned down everyone close, the most powerful radio is showing -62 at the AP.

Thanks,
Ben

Are all of the SM’s that are connected to that AP with 10db power level of each other?

yes, its probably more like 10 - 15 depending on what time of day you look.

I’ve seen issues myself with connectorized P10s giving very poor signal readings. We usually end up swapping out the unit with another one and all is well. Not sure if this is the case with the indoor units but if you haven’t tried it yet, maybe just bring another unit out there to test with.

is your poor reading on the SM or the AP? mine seems to be the oppisite, but only with some radios, the AP is seeing the SM poorly.

Has anyone heard of an SM that start to quit talking, i have heard alot about radios going deaf but not the other way around.

Mine has always been with the transmit, so the AP not hearing my SM.

benanthony wrote:
is your poor reading on the SM or the AP? mine seems to be the oppisite, but only with some radios, the AP is seeing the SM poorly.

Has anyone heard of an SM that start to quit talking, i have heard alot about radios going deaf but not the other way around.


The problem with P10 units "going deaf" or can be on either the Transmit or Receive side or both. It is more common the the receive but can happen on the transmit. I would suggest swapping out the SM for a different one or a P9 and see if that solves the problem.

I have stocked up a few P9 SMs that are setup solely as test equipment. Our installers use these to find the signal before installing a P10. They verify the install location with the P9 by checking signal and jitter levels at both the AP and SM. They also do a link test with the test unit. That way when the P10 is installed and it shows significantly worse readings it does not get installed. Those units that do not perform are marked and returned to the office for RMA.

what is your RMA percantage? we started with 25 indoor and 35 outdoor, we are now down to around 10 left total and I have not RMA’d a single one. Maybe some of these are bad and I just don’t know it because they are close enough to the tower to still work, just not like they should?

If the SM is close enough and gets such an amazingly strong signal then it can be hard to identify until it finally dies.

I probably RMA 1-2 out of every 25 pack nowadays. The first few months of P10 units it was more like 4-5 out of every 25 pack. So it will depend on how old the units you have are?