On Mon, 31 Jan 2011 09:39:10 -0500, Hanz
wrote:

Can I use the 735 without the antenna tuner to only receive signals (no
transmission)? What happens if I key the mike without the antenna tuner?

You can but reception will usually be better with a tuner. On
transmit you will have a high SWR (Standing Wave Ratio) due to the
mismatched impeadances. The radio will try to protect itself from
damage by reducing power output to a very low level. I'd disconnect
the microphone to protect against accidental transmission.