N4HY responded to S56A's surprise at ON4UN's copying of 45 bauds
Murray code through a 150 cycle filter:
Though I have strong doubts as Mario, this one is not warranted.
I will await with anticipation the ARRL Lab tests.
With modern RTTY programs and TU's, you can copy RTTY with one
of the tones completely missing. This is because all of the
good ones for two decades after Dave Mills taught us all how,
use a sliding threshold for the slicing detector. Given the
constant group delay through the FIR filters in the radio,
I suspect John's statement about RTTY to be completely
correct. Do not try it however under weak signal or QRM
conditions. That test is a strong signal test primarily.
Mario is correct - bw = shift + (2 * rate).
John's TU or soundcard software or whatever did a good job of working
off just the mark or space tone, or if it was on both, then with how the
Orion mangled them.
Since pre-detection bandwidth was only slightly less than width of the
signal, then the amount of mangling is minor & to conclude it was
working good is not too hard to understand.
Crank it down much more & it will start to look bad.
Kinda like if Mario tried to drive his Chrysler through a gap that is okay
for my Subaru - on the other side, they both will be functional cars, but his
will have some serious damage down both the near & offsides.
Instead of establishing how good the gap is, we learn who are the best
panel-beaters. ;^)
73, VR2BrettGraham
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