IQ Sample data doesnt change at all

I seem to have a strange issue with LimeSDR. When I try to get GPS IF IQ data out, the IQ data doesnt seem to change at all. I tried collecting it from Pothos, used GNSS_SDR and then finally tried with SoapySDR api’s.
The parameters are like this -

  1. Center frequency - 1575.42MHz
  2. Bandwidth - 2.048MHz
  3. Sampling Frequency - 4.096MHz
  4. Gain - 60dB

The value doesnt change whether I use an active antenna or whether I use a passive antenna.
Can I get a replacement board of LimeSDR?


@venk - Venkatesh,

There are three gain controls used with the LimeSDR and when I used them for GNSS_SDR using Ubuntu I set them to the following settings:

PGA = 31
LNA = 15
TIA = 2

The full disclosure on how to get your LimeSDR to play on GPS is at the following link:

I would highly recommend that you read ALL the threads on that page even if you’ve played with GNSS_SDR already. There’s a TON of information how all of us got it working with the LimeSDR and it really plays fine with it…!

Hope this helps - 73 de Marty, KN0CK

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Hi Marty,
Thanks for the inputs. I have tried all these mentioned in the forums. Finally I wanted to see if there was any toggle in the IQ data as the histogram was completely biased (also the range was not in the space of +/-1), To which I found that IQ data had this kind of a plot for which I didnt find any explanations.
Therefore I opened a new post.
I think my Lime is bricked. Any ideas will be of great help.