Didn't change the length of Radio tx by increasing payload

[fatemeh ghasemi]

I have nrf52832 platform and my version of softDrive is (nRF5_SDK_15.3.0_59ac345). I red a lot of documents and tech support like these links but couldn't find my problem.

https://devzone.nordicsemi.com/nordic/power

https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/nrf52-online-power-profiler

https://devzone.nordicsemi.com/f/nordic-q-a/47930/uart-ble-example---data-size-limit/190550#190550

https://devzone.nordicsemi.com/f/nordic-q-a/5167/nrf51822-s110-large-ble-packets

https://devzone.nordicsemi.com/f/nordic-q-a/553/dealing-large-data-packet-s-through-ble

https://devzone.nordicsemi.com/f/nordic-q-a/51993/ble_gatt-sd_ble_gap_data_length_update-request-on-connection-0x0-returned-unexpected-value-0x13/211598#211598

https://devzone.nordicsemi.com/f/nordic-q-a/54891/how-increase-data-packet-length-and-pdu-length

and etc

my problem is according online power profiler when we increase the number of payload until 27 the length of Radio Tx is increasing and after 27 until 216 we have more spike for Tx, I did exactly the method for 2 application (heart rate and mouse ) but neither length of Tx changed , nor number of spikes changed. but when I increased the payload more than 256(in my sdk it was 256 according to source code) the plot was crashed, it proves payload is increasing, so why I can't see the effect of that? how I can track number of payloads and see receive and transfer bytes? 

I wrote a code for large data and split it to small packets (244) and again I didn't see any change in lengths and spikes. 

I investigated all of the documents and source code and really don't know what is the problem. please help me for solving the problem.

[Sigurd]

I increased the payload more than 256(in my sdk it was 256 according to source code) the plot was crashed

 Note that the maximum MTU size is 247 (NRF_SDH_BLE_GATT_MAX_MTU_SIZE), and the max data length is 251(NRF_SDH_BLE_GAP_DATA_LENGTH). I believe the ble_app_uart example is the best example to use for testing this, and for sending payloads with different lengths(ble_nus_data_send() is used to send the data.)

but neither length of Tx changed , nor number of spikes changed.

 What tools are you using to measure this ?