When is class C no longer good enough for digital modes?
On Mar 11, 9:41*am, Tim Shoppa wrote:
Class C operation seems very well suited to HF CW operation. At least
if the resulting envelope looks "nice" by ARRL handbook definition of
keyclick reduction, I guess.
But is it good enough for RTTY?
How about for PSK-31? Olivia?
What I've got is an old Eico 720 (Novice 75W-class transmitter biased
for deep class C, for those too young to remember) that I currently
use for CW, but would like to try out for RTTY or maybe PSK-31 by
feeding appropriate waveforms into the "VFO in" jack. My gut feeling
is that RTTY would be OK but don't really understand how class C will
mess up the PSK-31 waveform or introduce intermod that will make the
resulting spectrum broader than necessary.
The Class C stages will clearly fail the usual SSB two-tone testing
but what is a more appropriate test to say that it's good enough - or
not - for PSK-31?
Tim N3QE
Its not just a matter of whether or not it will work but whether it
not it will work within the confinments of the allocatted bandwidth. I
think any mode normally used with a SSB transmition would probably
flunk this test.
Jimmie
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