Warm up time about 45 Minutes, But after that very stable and extremely sensitive for a 50 year old radio.I've compared this unit up against my newer radios and "Wow" It Knocked me over is all I can say! Connected to the right speaker 3.2 ohms ( I use a Drake MS4 ) Rich full audio one do's not tire from . I would rate it 4.5 if I could on your chart. The VHF 144 TO 148.00 mhz ( Which you did not comment on in the specs ) Works very well but only in the ssb or Am modes. To operate it in this mode one pulls the AF knob out and then your into 2 meters which is on the top right side 1/4 moon dial. If you can find one of these radios in working condition pick it up you won't regret it for that antique CLASSIC RADIO in your shack. 73 ve7dh