The WiSense WSN1101L Sub-Ghz wireless mesh node uses the CC1101 transceiver from TI. The CC1101 has a max power output of +10.8 dBm in the 865-867 MHz Band. The CC1101 has a special transmit mode in which it outputs an unmodulated continuous wave (CW) signal (sine wave). This mode is useful in testing the radio board’s performance. The snap below shows the radio board’s output with the CC1101 configured to generate a 10.8 dBm unmodulated continuous wave signal at 866 MHz . Note that in this setup, we had a WSN1101L connected to the spectrum analyzer’s input through a RF cable assembly. The spectrum analyzer is measuring an average channel power of 9.05 dBm. The power loss (+10.8 dBm – 9.05 dBm) can be attributed partly to the RF cable assembly.
If you are wondering why the frequency domain representation of a continuous sine wave is not a single thin vertical line – it is because of phase noise.
The pic below shows the setup – A WSN1101CL connected to a spectrum analyzer.
We are currently evaluating an RF front end module which will increase the range of our WSN1101L and WSN1101CL nodes by increasing the link budget in both the transmit path and the receive path. The max transmit power of our nodes will go up from +10 dBm to +30 dBm which is the maximum allowed power at the output of the radio in the Indian 865-867 MHz license free band. This IC has a low noise amplifier (LNA) to increase the link budget (thereby range) in the (RX) direction.
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