A mobile radio transmitting at 70 watts will draw approximately 15 amps. You need a power supply that is capable of delivering at least that much current continuously unless you keep your transmissions very, very short.
If I were you, I'd look for an Astron RS-20A or RS-35A (or the "M" variants which have Volts and Amps meters) or an Astron SS-25 or SS-30 (or the "M" variants). Astron's RS series are linear power supplies which mean they have big, heavy transformers, but they are very reliable. The SS series are switching power supplies which means they are lighter and smaller, but they are often more expensive than the linear power supplies. You may get advice to stay away from switching power supplies due to the RF they create, but the Astron power supplies are designed for communications service and, in my experience, they are very quiet.
Astron has been in this business for a long time and, to the best of my knowledge, Astron power supplies are made in the U.S.
I have both an RS-35M and an SS-25 that have never missed a beat.