[Milsurplus] BC-230 questions and observation

[Hue Miller]

Thinking about the harmonics from the BC-230 issue some
more:

Jack, i think your test would be valid, if you use a purely 
resistive load. I also think loading the BC-230 with a pure
resistance, like first 35 ohms to represent a vertical 1/4
wave, and next,  6000? ohms, to represent a vertical 1/2
wave, will give you a figure for harmonics that will be real-life 
and worst case, both, because the harmonics see an antenna
that is also not reactive either capacitive or inductive. That 
simplifies things. I also think this is a valid worst case, because
the aircraft horizontal antenna, which is a "low, horizontal" 
antenna, has much lower radiation resistance than the vertical.
The Sandretto book points out that with this coiltap system,
it is less efficient for low radiation resistance values, because
the low radiation resistance tends to be swamped by the
actual resistance and losses of the tank coil. In fact, for 
one example on ~3000 kcs, they calculate a matching circuit
efficiency of about 50%, and this even reckoning the antenna
coil Q is a generous 300.
I think the actual very worst case, for harmonic radiation, is
the vertical, hi-impedance 1/2 wave. I don't know any easy
way to do this one, with your spectrum analyzer, with its 50
ohms standard.
Hue Miller