Is the radio the new Cobra or the old Cybernet 121 boarded radio.
If you have the new one you'll find the information on cbtricks.com
Click on radio information then C for Cobra and look down the list for your radio.
Dave
My mistake, L21 ajust high power but all I can get out of it is 17 watts. Geuss I need to have it peaked and tuned. Except for this 150 I have aways been able to do it myself.