Mark wrote:
1) Filter Shape: From the discussion that Doug Smith gave at last year's TT
hamfest, I thought that the filter shapes would be adjustable, something
like Icom's sharp vs. soft filters. I find no mention of that in the manual,
and there doesn't see any way to adjust that. I've also noticed that the
filters seem somewhat wider that similar filters in the RX340. When I set
the RX340 filter to 100 Hz and run the audio through a computer program with
a waterfall display, I see a black background except for a 100 Hz wide
bright spot at the filter location. With the Orion, the bright spot is about
200 Hz wide with a 100 Hz filter selected
Your results are consistent with what N4PY measured
previously:
http://dayton.akorn.net/pipermail/tentec/2003-May/033783.html
You'll notice that shape factor is automatically widened as
bandwidth decreases which I believe is done intentionally to
reduce ringing. I've also asked TenTec about the bandwidth
discrepancy at 100 Hz since it has been measured by various
people from 150-175 Hz. This could be a firmware revision if
it is not behaving correctly. Most of the other 6 dB bandwidths
N4PY measured appear to closer to expected results.
73, Bill W4ZV
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