jks

I looked at your Kiwi. The transverter was inline so I couldn't evaluate HF. But even that looked much worse than before. Lots of small carriers everywhere.

I fixed the config.js file so it says "Air Band" now instead of "Amateur".

Also the software update to v1.282 was perfectly fine.

From the CHANGE_LOG file:

v1.281  April 12, 2019
    Add URL parameter "peak" to set spectrum peak hold mode (overrides last value saved in cookie)
        e.g. "&peak", or redundantly "&peak=1", but more usefully "&peak=0"

    Audio FFT:
        Allow URL parameter "no_wf" to be used in 4 and 3-channel modes, not just 8-channel mode.
            This is useful e.g. if you want to use the audio FFT to study the frequency response of
            the new de-emphasis filter in 20 kHz mode (3-channel mode) where you would otherwise
            never be given the audio FFT because there is no shortage of waterfall channels.
        Added missing window function to FFT.
        Fixed scale/waterfall click frequency in non-IQ modes.

    Added signal generator extension. When enabled replaces ADC input to audio/waterfall DDCs
        with a tunable RF signal source using the same FPGA DDS IP block used by the DDC mixers.

        WARNING: Be careful about drawing conclusions re Kiwi performance and possible bugs
        when using the sig gen. It reveals spurious responses in the waterfall/spectrum to a greater
        degree than if you just tune around with an antenna connected. But without detailed
        experimentation it can be difficult to know where the limitations are. Remember that the
        Kiwi is a carefully balanced compromise to get 4-channel mode to work (i.e. fit in the FPGA
        and have enough Beagle CPU cycles). So the DDSs, mixers, DDCs and FFTs are not perfect.
        Speaking of compromise, when considering FFTs it's important to understand this:
        https://en.wikipedia.org/wiki/Spectral_leakage

From the CHANGE_LOG file:

v1.281  April 12, 2019
    Add URL parameter "peak" to set spectrum peak hold mode (overrides last value saved in cookie)
        e.g. "&peak", or redundantly "&peak=1", but more usefully "&peak=0"

    Audio FFT:
        Allow URL parameter "no_wf" to be used in 4 and 3-channel modes, not just 8-channel mode.
            This is useful e.g. if you want to use the audio FFT to study the frequency response of
            the new de-emphasis filter in 20 kHz mode (3-channel mode) where you would otherwise
            never be given the audio FFT because there is no shortage of waterfall channels.
        Added missing window function to FFT.
        Fixed scale/waterfall click frequency in non-IQ modes.

    Added signal generator extension. When enabled replaces ADC input to audio/waterfall DDCs
        with a tunable RF signal source using the same FPGA DDS IP block used by the DDC mixers.

        WARNING: Be careful about drawing conclusions re Kiwi performance and possible bugs
        when using the sig gen. It reveals spurious responses in the waterfall/spectrum to a greater
        degree than if you just tune around with an antenna connected. But without detailed
        experimentation it can be difficult to know where the limitations are. Remember that the
        Kiwi is a carefully balanced compromise to get 4-channel mode to work (i.e. fit in the FPGA
        and have enough Beagle CPU cycles). So the DDSs, mixers, DDCs and FFTs are not perfect.
        Speaking of compromise, when considering FFTs it's important to understand this:
        https://en.wikipedia.org/wiki/Spectral_leakage

Jim, let me know if you get kiwi_nc working. I got it running to the point of producing output but haven't tested it beyond that.

For Mac people, I just found this work by Chris yesterday: https://www.blackcatsystems.com/software/kiwiSdr-sound-client-virtual-audio-device.html

v1.279 has improved spectrum filter options. In addition to the default IIR filter you can now select an MMA (modified moving average) and EMA (exponential moving average) filter or no filtering at all. There is also a new slider for the parameter associated with each filtering algorithm:

IIR: param = gain coefficient 0..1 (slower..faster)
MMA: param = averaging size in samples (1..64)
EMA: param = decay period (averaging size) in samples (1..64)

The URL parameter options sp= and spp= allow the filter and filter parameter to be preset in the URL. See http://kiwisdr.com/quickstart/index.html#id-user-tune

I implemented a minimum decay rate for the IIR filter. For various reasons the filtering is implemented after the waterfall colormap scaling. And with a more restricted colormap range (i.e. WF min slider less negative so no-signal waterfall area is black) the IIR filter would not decay for small signals as was observed.

There is also a new "GND" momentary button (i.e. click/touch and hold). This zeros (grounds) the waterfall/spectrum input data so you can see how the various spectrum filters decay under no-signal conditions.