This is from the radio reference wiki. You have to have Signal Stalker 1 to do that and Pro-106 has signal stalker 2
Signal Stalker II
Signal Stalker II allows you to watch for activity on all band frequencies or Police/Fire frequencies only. You can also turn on/off frequency sub-bands using the corresponding number keys.
Signal Stalker II will not work in the background like Signal Stalker I or Close Call.
Once an active frequency is found, the transmission is played through your scanner’s speaker, and you can quickly store it in any of your scanner’s memory locations.
Signal Stalker II functions by rapidly sweeping through the RF spectrum in 1 MHz segments. If RF signal energy is detected in a 1 MHz segment, Signal Stalker II will sweep through the 1 MHz segment in finer steps until the source of the RF signal energy is found.
You can change the normal Signal Stalker II operation to the Special Signal Stalker II operation. If you lock out 5 frequencies within a 1 MHz segment, the scanner will skip that segment in subsequent sweeps.
Available on the Pro-2054, Pro-97, Pro-2055, Pro-163, Pro-164, Pro-106, and the Pro-197.