If you get an NMO mount you can use antennas interchangeably. This mount would work

https://www.amazon.com/Tram-Mirror-Mount-Coaxial-Cable/dp/B00IDTJ1VY/

An antenna like this is good the frequencies most public service systems use.

https://www.amazon.com/Larsen-NMO150-450-800-Tri-Band-Nmo-Antenna/dp/B00P9JAVF6/

Make sure to get the appropriate fitting or adapter to match your scanner. Good luck.

Also check out NMO mounts from Breedlove. They are top quality and even have truck stake mounts and one's that fit around bed covers.

https://breedlovemounts.com/

Edit: Added Breedlove Mount info.