[ARC5] Lopsided modulation

[Richard Knoppow]

    I would add, as I did in a previous post, that a _loaded_ 
final tank has rather low effective Q. It is desirable in most 
cases to maximize the Q of an _unloaded_ tank but when connected 
to a load the load impedance is imposed on the tank. That is why 
the dip in plate current at resonance becomes less as the loading 
is increased. At some point the plate resonance can be see more 
easily as an increase in power. If the amplifier is properly 
neutralized this peak should be coincident with the dip in 
current and can be easier to see when the load is near optimum.
    I suppose a tank with low loading and mis tuned for the dip 
could be far enough off resonance and maybe sharp enough to 
reduce one sideband but I think it would have other problems at 
that point.

On 2/27/2018 11:27 AM, Tom Lee wrote:
> Yes, the muddle is very odd. Bob said it succinctly and 
> correctly: The shape of the modulation spectrum has no impact on 
> symmetry of the sidebands. For pure AM or pure FM, you get 
> symmetrical sidebands, period. As a professor, I leave it as an 
> exercise to the student to compute how high a tank Q would be 
> necessary to produce a pronounced asymmetry (hint: you will find 
> it hard to contrive sensible numbers in most cases). By far the 
> most common source is the simultaneous occurrence of AM and FM. 
> It is difficult to build a modulator/transmitter chain that is 
> completely free of incidental modulation by the unwanted mode.
> 
> Cheers
> Tom
> 

-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL