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cariboulabs / cariboulite

CaribouLite turns any 40-pin Raspberry-Pi into a Tx/Rx 6GHz SDR
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RF signal emission when in RX mode #112

Open dboyan opened 1 year ago

dboyan commented 1 year ago

One biggest issue I discovered after toying with the device is that it has various strange peaks in the spectrogram when receiving signal. After diagnosing (in vain) the digital interface and DMA on the FPGA, I discovered that the device is actually emitting RF signal when it is on in RX mode with the help of another SDR device I usually use. Just like in the image below.

leak-hif

The SDR++ window on the top is connected to my cariboulite in remote mode. Meanwhile, the waterfall graph below is from my other SDR device using gnu radio, receiving on the same frequency. I'm pretty sure that the red lines below are the emissions from cariboulite because they disappear as soon as I stop the receiving with SDR++. The emission can be observed from both S1G and HiF ports.

zbyrek commented 1 year ago

In worst case scenario this could be mixer leakage, so can't be fixed in software.

edit: I checked mine with direct connection and there are no emissions on rf port. image