I have made a step-up regulator system and so far (in my workshop) it works fine. I will be testing it out in the field shortly to see whether it picks up interference at all. The voltage out is completely devoid of any noise and in fact puts out a better (less noisey) voltage wave form than the normal regulator. However, when I get into the field I will have a better idea as I have performed mods to the detectors before that are hopeless in the field. So let's keep our fingers crossed. For those that aren't aware of these systems, the step-up regulator works from a standard 6V SLA (or anything around 6-6.7V) and boosts the voltage up to (in my case 6.9 - 8.5V variable) whatever you want while also keeping the current at the normal draw. (This is limited to 3Amps but as our detectors draw no more than 1.0Amp, we will not have a problem with large coils or heat.) In fact whilst testing with my biggest coil the regulator doesn't even run warm, unlike the standard regulator. The heat factor for this operation is around 1.5  Watts only as opposed to around 11watts.

So keep watching here for updates and I will let you know if & when all is okay.