G'day
Have always carried a uhf radio with me while detecting with the gpx or sdc, and have never had any issue with any other pi machine I have owned with the uhf radio being on either while detecting, also I don't carry my mobile while detecting out bush as normally don't have a signal so I leave it in the car attached to the base antenna, I do however carry my mobile phone when I am coin hunting in the burbs when using my vlf sovereign gt, and once again have not experienced any issue with it while detecting or even when answering a call while the detector is still going.
Many other things can cause interference with detectors, particularly pi machines with picking up emi, and also some people have reported issues with using a pin pointer while the detector is on but that's about it.
cheers
stayyerAU