Best rooftop antenna for my conditions

[Fdxdoeboy]

I live around 32 miles from Philadelphia and can currently sporadically pickup their p25 police radio transmission from my deck with my Motorola non affiliated scanner on a rubber duck, its coming in extremely scrambled if at all at times, if I get in the car with the radio I start to pickup the signal around 5 miles away from my home. My sds 100 doesn't pick it up at all. Curious what rooftop antenna may give me the best shot at pulling in the signal. I had my eye on the Diamond d3000n discone however I know this antenna doesn't have any gain and i'm not sure if it would work without any gain. The antenna will be mounted 30 feet up on a j-pole Any input from the experts here would be appreciated below is my line of site to Philly Thanks

 

[prcguy]

What frequency range?

 

[Fdxdoeboy]

What frequency range?

800-900

 

[prcguy]

800-900

Discone is not a good choice for that, they can be many dB down at the horizon above 500MHz.

 

[popnokick]

If all that you want to hear / listen to comes from the direction of Philly and is only in the 800 mHz freq range, get an 800 mHz beam / yagi antenna and point it toward Philly. If you listen to other things besides Philly 800, consider an omnidirectional wideband antenna such as the DPD OmniX. Your clear line of sight to Philly and 30 ft above where you are and the fact that you are receiving some of it sporadically now, it's likely that even an OmniX will receive Philly 800 from your location.
OmniX Scanner Base Antenna

 

[Fdxdoeboy]

If all that you want to hear / listen to comes from the direction of Philly and is only in the 800 mHz freq range, get an 800 mHz beam / yagi antenna and point it toward Philly. If you listen to other things besides Philly 800, consider an omnidirectional wideband antenna such as the DPD OmniX. Your clear line of sight to Philly and 30 ft above where you are and the fact that you are receiving some of it sporadically now, it's likely that even an OmniX will receive Philly 800 from your location.
OmniX Scanner Base Antenna

Great info, I appreciate the reply..