Yes, this is an old one that's been done to death in other forums, having been a contributor myself. In the last decade, with much lower power outputs from computers, mobile phones etc., the problem seemed to be going away, but it hasn't. I was considering initiating a whole new thread for a recently encountered problem, but thank youHomer_J, you did it for me.
I was very recently operating a flight to India, and encountered severe interferance on the VHF frequency in use (133.8), to such extent that frequency change was necessary, and, at a later time when 133.8 was the only VHF frequency, had to resort to HF. Complaint to ATC that they were unreadable, and that the interferance was coming from an obvious series of mobile phone calls, had no response as no-one else was having a problem. We were the only affected aircraft, which obviously meant that the interferance was coming from within our own aircraft. We could hear the phone conversation with considerable clarity.
I had the cabin crew conduct a search, and sure enough, found the culprit who was using a 'state of the art' phone. I'm not au fait with current models, but it was referred to as either a blackberry, or blueberry.
The interferance caused was total, but seemed isolated to just that one VHF frequency, 133.8. After the offender ceased his third phone call, the problem stopped.
The problem was diminishing, it's back.
With respect to the cloud noise, it was common on the DC9 to hear a 'screeching' sound when passing through Cirrus cloud. I never had verification, but common folk-lore had it that it was caused by impact with ice crystals. Maybe so, maybe not.
Regards,
Old Smokey