Is there a better antenna for this scanner?
If your sole target was San Angelo's P25
system, the best antenna would be one of the Remtronixs 800MHz antennas.
But your County,
Tom Green, and the VFDs in the county, are Vhf-high, which is not the best target for the 800MHz antenna. Your neighboring counties are also using Vhf-high. While the Remtronix antenna is not totally deaf on Vhf, you'd need a stronger signal to hear the county and your neighbors. I've had good results with the Diamond
RH789. It's available with a BNC connector (you'd use the SMA->BNC adapter that came with your 436HO), or with an SMA connector (no adapter needed), the SRH789. That is a telescoping antenna, and it has markings on the antenna for how far to extend to optimize a specific band. I use this antenna on my SDS200, with one section extended, and get good coverage in my area. There are number of 700/800MHz trunked systems in the DFW Metro area. However, Dallas PD & FD use Uhf. Dallas County, a number of the smaller suburbs, as well as cities in neighboring counties, use Vhf-high. No antenna will be the absolute best in every band, but the 789 works for me as a good compromise solution.