how do you range check a radio?

What kind of radio do you have? 2.4g or 72mhz? I have a 2.4 futaba 7c, and there is a power down feature that you enable, then walk out 50ft or so and check the surfaces. With the 72mhz radio, you collapse the anttena, and do the same thing.

Antenna down. Rx and TX on (engine not running) . Have a friend at the field watch your plane. walk at least 40 paces away from the plane. Start working your controls. Ailerons, rudder, throttle, elevator. All these should work as expected with no "hiccups" from this distance (@ 100ft) with the antenna down. This procedure is for a FM Tx and Rx. not sure about 2.4 checks, but assume they are the same. I'm just a rookie pilot, others may have more tips. but that is the procedure in a nutshell.

with a new install I would range check a 72mhz at least 100-150 ft with the antenna collapsed, engine/motor running (use helper or tiedown of course). antenna pointed directly at the model and model's antenna parallel to your bearing gives the weakest signal (i.e. worst case scenario). Of course the manufacturer usually has good guidance. If there is a significant range difference with the engine off, (>10%), it needs to be fixed before flying.

I always do range checks. One with the engine not running and one with it running. Just another double check for safety sake. Good Luck, Dave