On Jun 29, 2006, at 8:35 PM, Joe Subich, W4TV wrote:
> Gary writes:
>> That is exactly Rich's point. The degree of loading has no
>> effect on VHF energy.
> Gary, you make the same mistake Rich does ... the voltage is
> not necessarily due to parasitic oscillation at VHF frequencies.
Not a sound wager.
> An unloaded tank can generate voltages several times that of the
> applied (plate supply) voltage depending on the Q and impedance
Can an unloaded tank reach potentials higher than the breakdown
voltage of its Tune C?
> Since the tube is not operated in class A,
> harmonics will be generated and, particularly at 10 meters,
> some of those harmonics will certainly extend to VHF (3 x 28
> = 84, 5 x 28 = 140). Again, that is expected behavior.
> What is important is that the tank be properly loaded,
The problem in this case is that a HF/MF low-pass Pi-network tank
rejects VHF, so a VHF signal is not loaded -- i. e., it is rejected
by the low pass design.
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