Headware radios have a flux rating of 1.
you can boost it up to 4 with a signal booster, installed into a cyberarm.
be aware, that encrypted password receving radio detonators are very expencive.
it's much cheaper to just get the cheap ones, and set them to detonate when they receve a signal of 14.3 megacycles on frequency 1123.8
there is a chance of stray transmissions setting them off, but it's not a very big chance.
hot mikes do cause problems though, in either case.