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Cabal likely uses a VHF / UHF system, using digital modulation - P25 or DMRS, very likely also encrypted.
True.
On the other hand, GMRS/FRS is easily monitored, it'd be the first place I'd look if I wanted to monitor someone who has minimal knowledge of radio. Then the CB band.
Alternatives certainly exist, and depending on the security required, can get rather complicated. You could always operate clandestinely where nobody would even think to monitor.
For wide-band HF usage, I recommend a T2FD antenna. ARRL has been asked not to write about them, as their advertisers don't like them.
You lose a little efficiency, but gain a really wide bandwidth.