B11 two different "target" signal levels?


#1

Our B11 AP is doing 780 PHY receive and 650 PHY transmit. I was wondering if we could get that to around 780/780. I noticed that we have two different “target” signal levels on each end of the link. Should those not be the same or is that dependent on other factors?

Another question I had was if we mounted our antenna too low to the roof? Would that affect performance at all? We really dialed in the signal so I’d hate to move it now; but if it’s the 6dBm signal difference we’re seeing it may be worth it.


#2

I think you should turn down the power. Actually your SNR should be little above 30, so depending on distance and antenna gain RX power in most cases doesnt have to exceed -50dBm. If you see noise and you are shure that no one is in your frequency - you are self interfering and you should move the antenna.


#3

There’s no noise. That was the power level our coordinator had listed for us to use. It’s possible I misinterpreted the document and that was supposed to be the max power. Our SNR is 58.


#4

Hi Christopher,

Target signal levels are calculated per side of the link based on three factors:

  1. Remote EIRP (Tx power and gain)

  2. Local antenna gain

  3. Free space path loss which is calculated from GPS-derived distance

Transmit Power Control (TPC) may also reduce Tx power on the remote side to improve EVM at the local side if the transmitter is in compression and if the SNR is sufficient.

Low mounted antennas run the risk of Fresnel obstruction by the roof on the vertical polarization. You might try increasing the antenna height to determine if this is happening.


#5

Hi!
My levels are still much more differents…

In AP:
Target: -49.1 dBm
Signal: -50.2 dBm)

In STA:
Target: -37.1 dBm
Signal: -50.3 dBm

The signal received are equivalent in the two radios, but the target… 12dBm!!!
What’s going on here??


#6

Hi Alejandro,

This could be caused if you have different Tx powers or antenna gains on each side. TPC may also be making Tx power adjustments that are not included in the target calculation. Your link is very healthy otherwise according to cloud data.