A discone antenna works very well as a replacement for the ST2 as it also covers a wide range of frequencies. Good coaxial cable is key too. If you can afford it LMR-400 as it is also 50 ohms like a discone antenna and your radio antenna connection. Next is RG11 and after that is RG6 presuming your coaxial cable run is 50 feet or less on the last one. Get it above your roofline if you can.