I Peter, I have used the TM-V71A as portable with my ARROW II, works, great for SATs. also have one as base station and mobile. and use it for terrestrial packet. it puts out a fixed level voltage frm the dataport for packet so be sure if you use with a TNC it will operate at the levels of the radio.(9600 bd). its a great easy-to-program on-the-fly radio. 73 Christy KB6LTY