2021-10-12 12:21 AM
Details:
TX Power on Board: 14dBm (LP)
Omnidirectional TX antenna (on board): 2dBi
Directional RX antenna (LPDA): 4dBi
Distance: 0.5m free space with minimal interference in lab
Frequency: 868MHz
FSPL (868MHz @ 0.5m) = -25dB
Expected P_ in RX: -5dBm
Measured P_ in RX: -74dBm
If anyone has encountered something similar or knows how to boost the TX power (without using RFO_HP), please let me know, as I'm not sure that the board is actually transmitting 14dBm.
2022-11-14 12:19 PM
Did you find the problem? I'm having a similar issue. The received power is lower than expected.
2022-11-14 12:50 PM
Perhaps put a power meter directly on the SMA?
Check and/or instrument the Semtech register writing code so you can confirm what power mode the chip is using, and also the power/current limiter.
2022-11-23 08:40 AM
Tesla DeLorean,
Thank you for your response. It was helpful. Because of it I switched from trying to test with a modulated signal to a steady signal. I also tested with an antenna I had a datasheet for. After that the calculations for what to expect were much better.