TX Power issues

[Hass]

Hello,

I am using WM02F WiFi mdule with nRF7002 SoC and i am having some issues with the TX power measurement of the WM02F WiFi module while operating it in 2.4GHz. 

I have tested these modules (ordered from Fanstel and Jetreq Components) on the same hardware and experiencing the different TX power in 2.4GHz band in all channels (1-14).

So, I was just wondering if there are any settings I have to change in the firmware, so both modules (from fanstel and Jetreq) have the same Tx power performance. the only difference on these modules i can see is 40MHz crystal but with difference order info.

Thankful for your guidance!

[Szabolcs]

Hi,

could you please clarify the issue? What is the other module you are using? How are you measuring the TX power, what is your measurement setup? What firmware and settings are you using for measurement?

[Hass]

i am using the BT40F as a BLE and main processor on the board. The BT40F and WM02F are certified while being used in co-location. i am using network analyzer with an E/H filed measurement probes to compare the TX power from the WIFi module. Other than that i have used the EMC chamber to measure the WiFI TX power from the both (variants) radio modules. The firmware part is from the Nordic Semi development with recommended settings. (sorry i have a very little understanding of the firmware part of this since i have been developing only the hardware), that is why i was wondering if there are any special setting to control or can affect the TX power from the WM02F.

Furthermore, i can control the radio TX power (0-20dBm) with modbus communication.

Thank you in advance for your support!

  

[Samruddhi Jadhav]

Hello,

Is it possible for you to share your measurements? We can then review exactly where the difference in measured tx power is occurring and what it is. 

Hass said:

Furthermore, i can control the radio TX power (0-20dBm) with modbus communication.

Can you please clarify what you mean by controlling the output power via modbus here?

Best Regards,

Samruddhi

[Hass]

Samruddhi Jadhav said:

s it possible for you to share your measurements? We can then review exactly where the difference in measured tx power is occurring and what it is. 

Hello, Thank you for taking the time to looking into this issue! below are the measurements i have done in an EMC chamber using NA. The results below are when i set the WiFi TX power to 18dBm. 

WiFi Radio module (varient-1)


WiFi Radio module (varient-2)


Varient-1 and Varient-2 are the same WiFi module (WM02F WiFi module with nRF7002 SoC). only bought from different suppliers.  Almost 20dBm difference with the same TX power!

Furthermore, with controlling the TX power i mean, i can set the TX power of the Radio module. for exp i can set the radio module should transmit with 10dBm, 12dBm, 14dBm and so on.

Thank you!

[Samruddhi Jadhav]

Hello,

I am looking into this issue internally with our team and have received some feedback from them. Can you please verify the output power using conducted or cabled measurements? The images which you have shared seem to be of radiated measurements. Note that if the two designs are different, then the behavior of the antennas will be different as well, also according to their orientation.

Best Regards,

Samruddhi

[Hass]

Hello Samruddhi,

The images are from the radiated emission measurements. i have also tested with the E and H field probe to the NA and the result has been the same ~20dBm diff.

We have tested the radio modules from the both suppliers on the same board (PCB).

Best Regards

Hass