Manually gain control per channel in Kraken SDR

Hello, I remember in Kerberos SDR that the user has the ability to change the gain of the each receiver manually, so we could set different gain per channel. Now, I can see that when the gain is not set to auto and it is selected manually the same gain is set to all receivers. Is there any specific reason for that? Is it bad to set different gain per receiver? Should, we prefer the auto choice when the channels may have some offset in dB? (resulting from the spectrogram)

They’re set the same because the antennas are close enough together that the same gain settings can be used. The offset you see may be because of some antennas having better LOS or being blocked by the other elements, but tuning the gain won’t really help with that as it will also just raise the noise floor too.

Auto-gain is essentially experimental. We don’t have enough evidence yet to say if it actually helps or makes results worse.

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Should all the channels have the same receive power? One of the 5 receivers has 15 dB higher noise floor than the other 4 (these 4 have ±5 dB noise floor between them). How can this affect the DoA estimation?

In the KrakenSDR the noise floor doesn’t really affect results significantly because it’s based on phase measurements only.

Yes in the KrakenSDR hardware design one channel does have a higher noise floor which is not desired, but it’s normal and does not affect operation.

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