Sounds like RFI noise. Any new electronics near your antenna or in your house recently?
Not real familiar with the 996xt but if you can find out the NAC and the scanner has a NAC squelch (digital squelch), that would probably solve the issue too.
Not real familiar with the 996xt but if you can find out the NAC and the scanner has a NAC squelch (digital squelch), that would probably solve the issue too.