A few months ago I purchased a radio shack pro-433. I recently encountered a problem with static/distortion. The static only happens on my local PD dispatch freq. The frequency is in the 154.000 - 155.000 Fm range. I am about two city blocks from the city's tower. When the distortion comes it hisses and stops the scanner from scanning through the rest of the channels. I've tried the the squelch and have also switched between whip and attic antennas. The static came out of nowhere about a month ago, nothing before that. Any ideas....thanks.