It sounds like either priority scanning for a conventional frequency or weather priority. The brief interruption is your scanner tuning to the priority frequency to look for activity.
Priority scanning can only occur if it is enabled. This can be quickly determined on the right side of Line 3 when scanning. "PRI" indicates that priority scanning is enabled while "pri" indicates that priority scanning is disabled. It can be quickly enabled and disabled using the "FUNC" + "PRI" button. It can also be changed in the Global Settings menu. WIN500 has this located under the "General Settings" tab in the "Priority Settings" section.
If you are using priority scanning for trunked system and talkgroups, then the solution would be to disable it for any conventional frequency. On the scanner, this setting can seen when selecting any conventional object and looking on the right side of the 2nd line. "P" indicates enabled and "p" indicates disabled. This can be quickly toggled using the "PRI" button. In WIN500, this is under the "CONV Objects" tab under the "Pri" column.
To check for weather priority, go to the weather radio mode (WX) and check Line 3 for a "-P" on any of the weather frequencies. It will appear as "Wx#-P." It can disable by pressing "PRI" while stopped on that frequency. You can force the scanner to stop on all weather channels by turning down your squelch all the way and then stepping through using the up arrow or down arrow. In WIN500, this is located under "Weather Settings" and the "Weather Priority Settings" section.
