NRF52832 received signal strength jumping

[liu]

hello, I used NRF52832 as a ble gatway.Now i have a trouble that the received signal strength is jumping about 2dBm when the chip loaded program.I test it with Spectrum Analyzer. But, after the program is erased, the signal strength becomes stable. Now i cann't find the reason.Need your help urgently. Thank you.

[Matt]

So... an empty nRF52 can turn on the radio so that you can measure the rssi?

[liu]

hello, i uses a RF generator to give NRF52832 board a 2.4Ghz signal at the antenna location.

[MartinBL]

Hi, I think @Matt 's question was how can you possibly read out the RSSI without any code on your nRF52? Can you give us a step-by-step description of what you are doing?

[liu]

hello,

Now i have two troubles in NRF52832 Gateway.

1.Planning  introduce：

  The only function of NRF52832 Gateway is to scan beacons' advertisements.  With beacons‘ number is so huge，so we use three NRF52832 chips and scanning on 37/38/39  channels respectively.But we only use one antenna(SMA footprint) in this gateway. So  rear of this antenna is a LNA chip,after LNA chip is power separator chip(1 to 3).Three NRF52832 are connected to power separator directly like image1.     

2.PCB introduce:

F2 is LNA，U4 is power separator.RF lines(green )have made 50 Ω.Like photo 2.

3.Our testing method.

SMA antenna is linked with a Signal generator to gerenter a 2.4GHz&2MHz bandwith ble signal.We give the signal strength is -40dBm.

NRF52832 ANT pins is linked to spectrometer to see the waveform.

4.Our finding troubles.

1. Three NRF52832 chips‘ peak point of waveform is jumping about 2dBm when  it have burned programs.After erased the program, Three peak points of waveform is stable.

2.Middle NRF52832's signal strength is better than others 4dBm.
5.My Qus:

1.I guess the reason of these two troubles is length of RF lines is so long and not equal each other.
2.How to measure to find the reason causing this two thoubles,Network analyzer?
3.My testing method is appropriate or not.

[liu]

hello,

Now i have two troubles in NRF52832 Gateway.

1.Planning  introduce：

  The only function of NRF52832 Gateway is to scan beacons' advertisements.  With beacons‘ number is so huge，so we use three NRF52832 chips and scanning on 37/38/39  channels respectively.But we only use one antenna(SMA footprint) in this gateway. So  rear of this antenna is a LNA chip,after LNA chip is power separator chip(1 to 3).Three NRF52832 are connected to power separator directly like image1.     

2.PCB introduce:

F2 is LNA，U4 is power separator.RF lines(green )have made 50 Ω.Like photo 2....

3.Our testing method.

SMA antenna is linked with a Signal generator to gerenter a 2.4GHz&2MHz bandwith ble signal.We give the signal strength is -40dBm.

NRF52832 ANT pins is linked to spectrometer to see the waveform.

4.Our finding troubles.

1. Three NRF52832 chips‘ peak point of waveform is jumping about 2dBm when  it have burned programs.After erased the program, Three peak points of waveform is stable.

2.Middle NRF52832's signal strength is better than others 4dBm.
5.My Qus:

1.I guess the reason of these two troubles is length of RF lines is so long and not equal each other.
2.How to measure to find the reason causing this two thoubles,Network analyzer?
3.My testing method is appropriate or not.