Hello Markus,
Thanks for the efforts and your analysis. Your recent image (attached)
is convincing for me. There has been no veto so i think we can accept
that as valid.
73, Stefan/DK7FC
Am 04.11.2013 00:20, schrieb Markus Vester:
Today Stefan and I got a
long wav recording from Edgar J. Twining, starting 2013-11-01 16 UT,
shortly after the potential reception of dashes from DK7FC in Orford,
Tasmania. Signals from all three EFR utility transmitters (DCF49,
HGA22, DCF39) could be found in the recording. Using the same default
samplerate and LO settings that Edgar applies on his grabber, the idle
frequency from HGA22 appeared to be centered on 5429.95 Hz audio, which
is about 72 mHz lower than expected from the actual transmit frequency.
This offset is in good
agreement to the observed -75 mHz offset on the DK7FC signals, showing
that this was indeed a real reception.
Best 73,
Markus (DF6NM)
Sent: Saturday, November 02,
2013 1:59 PM
Subject: Re: LF: Tasmania?
...
From my
point of view, the best contribution to a "proof" would now
be verifying the receiver's frequency calibration offset. On
yesterday's screenshots, the HGA22 line seemed to be just half a pixel
below the tick. Simply by zooming in on it you could measure the offset
much better, even though the line is spread by some tens of milliHz due
to the FSK modulation. Last year I took some effort to measure HGA's
idle frequency in detail against a calibrated Rubidium source.
The result was 135430.022 Hz, with only very little
variation of a milliHz or so (see attached).
...
Sent: Saturday, November 02, 2013 2:31 AM
Subject: Re: LF: Tasmania?
Stefan, Edgar,
In my opinion this is a valid
detection. It would be very unlikely that pure noise would produce such
a result, and there has not been any indication of a spurious carrier
on this frequency in Orford.
The small offset in the frequency
calibration (about -75 mHz) is surely within expected tolerances of the
receiver's free running crystal oscillator. This is in accordance with
the Orford HGA spectrum, which shows the peak also very slightly below
the 135430.0 Hz grid line.
Best 73,
Markus (DF6NM)
Sent: Saturday, November 02, 2013 12:24 AM
Subject: Re: LF: Tasmania?
Hello Markus, LF!
Yes, i saw these 3 dashes (which are "dits" on that QRG and time) in
one line. And if they are from me, it must be the end of the 7. And i
was transmitting the 7 just to that time.
Did you place your grabber image overlay onto Edgar's image so it fits
the 3 dashes or did you place it so that the time stamp fits to your
time?
If "we" call this a valid ID and detection, then these 16833 km
are a new #3 world record distance on 2200m! (according to http://136.73.ru/h_qso/index.htm
)
Do "we"? Would others agree/disagree?
73, Stefan/DK7FC
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