> The stock Omni VI+ has a very sharp and discontinuous leading edge. The
> trailing edge is fine.
You can hear recordings of some radios at:
http://www.w8ji.com/keyclicks.htm
> It can be very difficult to design a transmitter with a symmetrical key
> shape while controlling power spikes with an ALC circuit. The behavior
of
> ALC tends to react to the onset of power by using feedback. Only, if the
> feedback loop is not fast enough to react to the initial power spike
before
> the time the ALC has settled, the damage is done. Alternatively, by
making
> the ALC respond faster, it tends destroys the integrity of the keyed
> envelope.
Actually a design that would correct this is very simple.
The technology that would allow a near-perfect solution is the recent
invention of a cutting-edge device called an op-amp (like an LM-358). It's
just so new they may be waiting for cost to come down so they are
affordable.
Seriously, it is only pennies and a few hours of design time to fix these
problems before the radio is built. The real problem has to be no one in the
design process cares.
73 Tom
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