[hpsdr] Problem with Powersdr 2.2.3 and Hermes

[Phil Harman]

Hi Andrew,
In answer to your questions:

What triggers the overload warning, is it the actual ADC overflow output or triggered by the input level exceeding a certain dBFS level determined in software (if so, what is it -1dBFS or 0dBFS etc??)

There is a pin on the LTC2208 that gets set when the ADC overloads. It’s this pin state the gets sent to the PC via the C&C data bits in the USB protocol.  Not sure exactly when this gets triggered but I would expect at +/- full scale. 

Incidentally, I notice that there is about as far as I can estimate a -7dB (maybe its 6dB, can't tell) difference between ADC input level (dBFS) and the level indicated on the Powersdr s meter set to read ADC level.

Have you calibrated PowerSDR with a known signal level at the antenna socket?

Is there any way to observe the actual ADC wideband level in dBFS??

KISS Konsole will display either the actual I and Q data being sent to the PC (after filtering and decimation) or an FFT of a 16k block of contiguous  samples taken directly out of the ADC – i.e. the wideband 0-55 MHz bandscope display.  At least with my Hermes and Mercury boards the displayed level is within 0.5dB of a signal from my HP8640B signal generator. 

73 Phil...VK6APH 
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