The Dongle’s R820T tuner chip has a frequency range of 24MHz to 1760 MHz. Therefore any strong RF signal within this frequency range (including 700 MHz) can overload the front end of the receiver (Dongle) and make it deaf to weak signals from distant planes.
The method given in the How-To " Do I Need A Filter? " scans RF signals in frequency range 800 MHz to 1200 MHz, so it wont show your Police Scanner.
There is another How-To which scans FULL frequency range of the Dongle, and is pretty fast too.
Spektrum - How-to Speedily Scan RF Noise in band 24MHz ~ 1800MHz
WITHOUT FILTER
WITH FILTER
