Mobile scanner USB interference-SOLVED!
Eureka! The 3rd try was the charm in solving my mobile scanner interference. I knew the problem was coming from the 12V USB cigarette lighter phone charger.... and had tried two other chargers up until now. Most recently a Kensington single USB port with a power indicator LED. But I was given a dual-port 3.6 amp smartphone / tablet charger made by iFlash and tried it yesterday. Took out the Kensington, put the iFlash in the lighter socket. Connected my iPhone to the charger, turned on the scanner, and headed out with the car on an errand. Interference was gone!
Before the iFlash, the Kensington unit used to cause the scanner to stop on a channel (mostly VHF low band, but some milair as well) and sound as though the squelch was open. All you would hear is hissing of an open squelch. However, no amount of squelch adjustment would remove the noise. You could turn up the squelch as high as you liked and scanning would not resume. Not only did that not happen anymore with the iFlash, but I discovered that the Kensington unit when it was charging my iPhone was also desensing my scanner even when it didn't stop scanning. I noticed much greater sensitivity on all bands when hearing the usual "locals" I listen to, and was regularly hearing both sides of the regional ARTCC air conversations... including the ground station / ARTCC remote base.
I'm not saying an iFlash dual-port USB 12V car adapter is the only one that doesn't apparently emit RFI garbage, and YMMV... but it's working for me.