I don't know if this is related to Tree's question or not but I suspect
it is.
In 1986 I went to operate CQWWSSB at Terry Baxter's (N6CW) old spot at
VP2VCW.
I brought an analog tape recorder and taped several hours of my 10 and
15 meter runs in the contest.
After the contest and after I submitted my log to CQWW, I was astonished
to see how many times the analog
recorder clearly picked up callsigns and qso information that I
struggled with or missed entirely while operating.
The reverse was also true - occasionally, but less frequently, my ears
picked up callsigns and qso info that was
inaudible on the recorder tape.
A few years later when I was in Seattle, WA and I was taking pictures of
sunsets with my digital camera,
I was amazed to see how much less colorful and dull the sunsets were on
than what I remembered seeing
with my eyes. The opposite was true when I had taken pictures of sunsets
in 1988 from Aruba (P40V) where the analog film showed wavelengths of
color that I never saw. Frankly, the sunsets were more striking on
analog film than my eyes could see, but the opposite was true with
pictures of sunsets taken on my digital camera one year later in
Seattle.
I don't know the disparity between I heard and did not hear with audio
at HF frequencies was/is related to the disparity I saw between the
colors of the sunset in pictures taken with my analog camera vs. what I
saw with my eyes, but they are all waves of energy being propagated in
different modes and then interpreted in our brain.
Maybe someone can enlighten me as to what I was experiencing and why
such differences between what I heard/saw and what the equipment picked
up? And is this in fact similar to what Tree described? It sure seems
that way.
Tnx & 73
Bob, KQ2M
On 2026-02-07 11:14, Tree wrote:
My take: for a SDR, if no signal was converted during the A to D
stage,
there will be no signal to "dig out" during the D to A stage
I find this very interesting. I can't say I totally understand the
issue
well enough to have an educated opinion. If it is indeed true that
going
into the digital domain eliminates the effectiveness of a "CW Speaker"
- I
think that is fascinating and makes me wonder what else is being missed
by
the human ear.
Tree N6TR
On Sat, Feb 7, 2026 at 8:17 AM Ron Spencer via Topband <
topband@contesting.com> wrote:
I think Dave and Adrian's conclusion is correct. My take: for a SDR,
if no
signal was converted during the A to D stage, there will be no signal
to
"dig out" during the D to A stage. No amount of signal processing or
noise
reduction will help since there is nothing there. Nothing is buried in
the
noise floor.
Ron N4XD
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