ICOM 7300 waterfall details

I realize the serial connection speed on the 7300 is what limits the frame rate for the waterfall update. But I am curious how the bandwidth is partitioned on the USB cable between the audio/waterfall/rig control. I assume the audio codecs have access to a much higher bandwidth over the USB connection than the waterfall/rig control, but would be fascinating to know the details on what the limitations are. Also curious about the resolution that gets transmitted for the waterfall, i.e. x pixels wide, y bits/pixel, z times/second etc.


The waterfall is simply sent over the 115200 baud serial converter per the CI-V Manual of the 7300. So despite having a few mbit to work with in USB, the waterfall is shuttled over the 115200 serial connection. Despite this, Icom runs the waterfall a bit slower than they could, likely as a safety margin against whatever polling other programs might run.

One day we’ll go inside that rig with some high speed logic probes and find the full-speed spectrum :-).

de W6EL

Thanks for the information - I am grateful for all the work you developers have done to make Wfview available for free, no less!

I am assuming the bandwidth setting for the waterfall has no impact on the serial bitstream rate, so it just puts out a higher spectral resolution for narrower frequency displays. But yeah, it seems like the frame rate could be a bit higher if the firmware would just allow it. Or let a user trade off spectral resolution for frame rate. I can imagine one of these years someone will reverse-engineer the ICOM code to re-structure how the USB data are partitioned.

I frequently use SDR# and the Spyserver program for remotely accessing my RTL-SDR dongles, and it is amazing how much audio & waterfall data they cram into low (upstream) bandwidth connections…on the order of 350 kbits/second for a combination of the audio AND a 10 frames/second waterfall.