Any aftermarket antenna that has a wide range of coverage will outperform the original antenna that comes with the radio.
If you want to focus in on a specific system that is 7 - 800 MHz the REM... 7 - 800 MHz antenna is superior and it works okay on UHF and I believe now they do sell a 7-800 MHz antenna that is also tuned for UHF, it's similar to the previous antenna but a little longer but it will give you more gain.
We are throwing spitballs against the wall here since we don't know what system you're talking about, we do have your location where we can find the county you're in and maybe find what system you are using that's attached this talk group. The diamond is a good antenna depending on what you are looking to listen to.
There are people out there who stand by the original antenna and say it works best for everything, it's a mystery to me why they would ever say that LOL. Good luck.