Dunno if your 9k does dual watch, where you can copy on two different freqs at the same time. Icom pioneered this methodology with the 781 as I recall, see here;
"The IC-781 was originally designed under a defence contract; the Dual Watch feature is quite well suited to guard-frequency monitoring in the same frequency range, or the monitoring of both frequencies in a half-duplex (split) situation. These scenarios often arise in some military/government HF operations. The utility of Dual Watch in the amateur radio service could well be incidental to the original design intent."
https://www.ab4oj.com/icom/dw.htmlIn my case the 775 and 756 P2 do dualwatch and I've found that even though there's a bandpass switch when tuning from 12464 to 8345, when the lower tuned freq is the primary it seems to work out well enough. To get the full sensitivity of the rig in dual watch mode on both freqs, those freqs have to fall within the same bandpass filter. The 8345 falls outside the 40m HAM band preslector, wich extends from 6MHz to 8MHz, the next extends from 8 to 12mHz, sadly cutting off 12464, but it still works out fine.
I can copy traffic on both easily enough with dualwatch. The sdrs available here do not cover the range one can employ with dual watch, but they do fine in the bandwidths they do provide for. I suppose most preselection filters in HAM rigs are of the sub-octave pie network type, wich offers a more or less symmetrical bandpass.
https://en.wikipedia.org/wiki/Octave_band
