5Mhz Tx

I’m trying to generate 5Mhz using Lime SDR USB and GNU radio. But power level is changing a lot.
The following massage contiguously displaying

“popping from TX, samples popped 0/1020”

please kindly let me know you suggestion.

Hello Thisara,
Samples from TX are getting popped because you are not giving enough samples to the Sink block before it timeouts, that’s why your power level is changing and the signal might even disappear.
Could you post the flowgraph you are using?


Thank you very much for reply. I found the problem . I used the “throttle” which is lowering the sample rate. I fixed it.

I have a another issue now. The received power levels are fluctuating. I used a RF signal generator (5MHz , dBm) . But still the power level not steady . Does it required a receiver tuneup? Please share with me if you know about Rx/Tx tuneup for 5MHz .

Thank you again

When using LO frequencies below 30MHz NCO is being configured automatically for you but not analog filters and calibration settings.
So, to receive at 5 MHz, set your desired sampling rate, keep oversampling default, set analog filter to 60MHz, calibration bandwidth to 60M. Preferably, leave LNA path to auto.

I need to use both the receivers (Rx1 and Rx2)at 5 Mhz. I did the lineSDR easy fix 1 for the both Rx1_L and Rx2_L. But Rx2_L does not works well. I saw there is another modification RX1_W and RX2_W impedance matching for Lo frequency. If I do the the bellow mentioned modification will the both channel works on 5MHz?

modification table 5