Familiar with the area. Looks like the system is just coming alive in the past few weeks?
The HP1 should receive it fine. Looks like no tower info on RR yet to review. If you are outside of Horry and trying to listen, one of the things that p25 systems have in common, they are directional oriented to be received within the county and not to reach outside to surrounding counties.
You didn't mention if you are showing any signal in the little top right bars. If not, then there could be a number of things.
If you are, then you should be receiving 859.7125 control channel, or one of the 3 alternates.
To verify this, go to menu - advanced menu - quick frequency entry. Enter the red or blue frequencies from RR and see if you get a digital control channel. It will just make motorboat noise, no talking or voice. If you are getting that, and you are getting at least 2-3 bars of signal when scanning the system, then you are getting it, but maybe for other reasons not receiving.
If you don't get a digital control channel noise, you are likely out of range or not directionally within the footprint. Or it could be a simulcast system, meaning you are getting a strong signal, but from more than one tower and they are cancelling each other out.
If you have the extreme option, you can try advanced - analyze system, trunked system analyzer. When it asks what system just press accept and your system should be there. Use the load/status option and it will show signal, quality, and activity. You won't hear anything but it will validate the system is active.
536/436/ws1095/996p2/996xt/325p2/396xt/psr800/396t/HP-1/HP-2 & others
