Since he's already tried two different antennas and meters, I suggest you try a different radio to see if the final stage is oscillating on a frequency outside of the antennas bandwidth.
I've had them oscillate right out the box.Bells has be known to crank 'em up.
Darn, got a new one still in box. Haven't hooked it up yet. Shopped around and noticed some reviews of shops tuning. Went with one from Clay's, even called before ordering. They took time to "talk with me" and explain their tuning. They wont crank it up just to be loud......best sound, best modulation to pwr. Every radio is different. Spec sheet values are : low pwr, 20w dk swing to 100w, high per, 100w dk swing 260w.I've had them oscillate right out the box.
Darn, got a new one still in box. Haven't hooked it up yet. Shopped around and noticed some reviews of shops tuning. Went with one from Clay's, even called before ordering. They took time to "talk with me" and explain their tuning. They wont crank it up just to be loud......best sound, best modulation to pwr. Every radio is different. Spec sheet values are : low pwr, 20w dk swing to 100w, high per, 100w dk swing 260w.
Finally broke dwn and bought it, and now reading recent failures is not settling well.
When the high power final stage uses transistors in a 3 terminal package, the chances of instability resulting from internal oscillations increases a lot. No matter what you place inside the package, you still can't get around those high inductance leads. The very nature of RF oscillations can be so unpredictable that it can be difficult to replicate all of the situations that can cause one to start. Testing on a dummy load just about eliminates your chance of detecting one without a spectrum analyzer. Even then, it may behave well with a purely resistive load.I've had them oscillate right out the box.