I have found the Motorola PMAT4001 VHF/UHF GPS antenna works well whether the radio is being held, or hands free using a BT mic. I have tested it against a Diamond SRJ77CA and the Moto was the winner, especially on VHF. Plus that Diamond is around twice as long. Also, that Motorola antenna may be the PMAT4001A. I am unsure of what the difference is between the two models, or if that is to designate country of origin.
Anyways, it works well enough that I also use that model on my XTS5000 VHF and UHF radios, as it is a definite improvement.