[ARC5] Re: Harmonic "suppression" in ARC-5s

[J Forster]

Not quite, I think.

There is a classic experiment in physics with two tuned circuits, each composed
of a large coil and resonating capacitor. First you sweep a single coil then
bring the second coil into coupling range, and the peak "splits" to form a
double tuned (rabbit ears) display. The degree of splitting is dependent on the
coupling.

In the ARC-5 Tx, there are two resonant circuits:  The plate tank & the
rollerductor-antenna capacitance. They are variably coupled by the link.

Too much link coupling will couple the two circuits too tightly and reduce the
overall Q of the system by double peaking, leading to reduced harmonic
suppression.

So, I'd think to achieve maximum suppression, you'd want to use only enough
coupling to get the power out, and no more.

-John


====================

Kenneth G. Gordon wrote:

[snip]

>
> Both the link settings AND the loading coil settings, in conjunction with
> the various capacitances involved, whether antenna or other wiring,
> constitutes, automatically, a kind of harmonic attenuator, since they
> ARE frequency dependent and frequency selective.
>
> If they weren't, then it wouldn't matter how you set either the link or the
> loading coil, as long as the final was tuned to the same frequency as
> its driver was.
>
> You had to adjust the loading coil, and the link, to achieve proper
> power into what ever antenna your airplane carried. And, if you
> changed frequency significantly, you had to RE-adjust those for proper
> power output.

[snip]