[ARC5] Audio power output - 10 meter BC-454

[Neil]

I think Ken, you're operating the receiver into a 500 ohm loudspeaker
which you have described as being in reality an 8 ohm speaker with
500:8 matching transformer.
The load presented may not represent 500 ohms at your 400 Hz test
frequency, explaining the very wide plate voltage swing calculated by
Brian. It would perhaps be more appropriate to use a resistor of 500
ohms.

73 de Neil ZL1ANM