Some quick tests with a Marconi 2024 signal generator, 10MHz carrier via a 10MHz BPF, Mini-circuits 4 way splitter and 6dB attenuator at -20dBm into the receiver
14bit KiWi MK1 2 x 10MHz = -60dBc Note that the KiWi ADC is close to clipping.
16bit WEB-888 2 x 10MHz = -63dBc Pretty close to the KiWi, despite having two more bits which should provide approx 12dB more dynamic range. I think the LNA, could be the limiting factor.
16bit RX888 and PhantomSDR-Plus, running at 82meg sample rate. 2 x 10MHz = -30dBc. I tried adjusting the gain, but it made very little difference.
The original message, with screen grabs, is on the NextGenSDR's IO group.
https://groups.io/g/NextGenSDRs
Regards,
Martin
The Smeter cant be really used, the Smeter is more like a db representation not like on kiwisdr / web888 (as these are the same)