@IgnasJ: Thank you. With PAD=52 and IAM=0 (equivalent to soapy gain of 52), what could be the expected output power, for instance for a CW or whitenoise signal of bandwidth 10MHZ ? And with PAD=52 and IAM=3 or 6? Could you make the test for me?
Here, I get -36dBm when sending whitenoise on 10MHz bandwidth at 2.45GHz.
@IgnasJ, @andrewback : any news? Could you test with GRC or Pothos what max value you get with a simple CW or Whitenoise signal?
I tested with a friend on his own LimeUSB directly plugged to his RF wattmetter, and we also got results far from 10dBm (around -26dBm)
Thanks @martywittrock ! Would you have the same data but at 2.4GHz ?
I’m going to try SDRAngel to compare with GRC and Pothos.
Can’t help you there - my spectrum analyzer only goes to 1500 MHz and all the measurements I made with my LimeSDR USB are based on three tuned measurements at each frequency to get the actual value (peak, and not too many varied that much measurement to measurement). There is data that @Karolis has performed on the LimeSDR USB and LimeSDR Mini for those frequencies above 1.2 GHz and they do appear on this forum if you do a search on ‘transmit power’. It also appears here on Myriad:
…and also here if you look at the curve more toward the bottom of the page:
https://wiki.myriadrf.org/LimeSDR_HF_Performance
Hope this helps -
73 de Marty, KN0CK
Hi,
I tested LimeSDR-USB output using SoapySDR API to send sine IQ samples .
Center frequency 2.45GHz; sine tone offset +1MHz; antenna BAND2; sample rate 10MHz; bandwidth 10 MHz.
I got the following levels reported by spectrum analyser.
Soapy gain=52 -> ~ -7.0dBm
Soapy gain=55 -> ~ -4.0dBm
Soapy gain=58 -> ~ -2.0dBm
Soapy gain=61 -> ~ -1.0dBm
distortion (additional harmonics) above gain setting 55 was clearly visible.
Thank you very much, @IgnasJ, it was actually the PA I put at the output that was faulty. My results are nearly the same as yours, so all is fine. Thanks again.