John,
No do it the way I told you antenna attached and adjusted to 7 inches. This will enable you to compare your distances to any other radio brand made. I own a 10X, 14MZ, and older JR 7 channel PCM's. It does matter what kind of radio you use when you set the transmitter antenna to a standard length.

If you want to do the range check with the antenna removed the baseline distance should be 300 feet, but the transmitter module might get a little hot.

Completely ignore what JR says... they are trying to sell everything they have no matter how bad it is. The 50 foot they suggest isn't good enough to put in a kite! Remember they don't want you to know the difference between junk and normal.
Lee H. DeMary
AMA 36099