Return to KLUBNL.PL main page

rsgb_lf_group
[Top] [All Lists]

Re: LF: DK7FC Equinox reception

To: [email protected]
Subject: Re: LF: DK7FC Equinox reception
From: Stefan Schäfer <[email protected]>
Date: Sun, 04 Aug 2013 02:41:44 +0200
Authentication-results: mx.google.com; spf=neutral (google.com: 195.171.43.25 is neither permitted nor denied by best guess record for domain of [email protected]) smtp.mail=[email protected]
Delivered-to: [email protected]
In-reply-to: <652B496A852640E69B77E2F9B2F1D1AF@White>
References: <[email protected]> <652B496A852640E69B77E2F9B2F1D1AF@White>
Reply-to: [email protected]
Sender: [email protected]
User-agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3
Hi Markus, Edgar,

Well i think it is most promising to start with the good old DFCW-180. If the success is clear and if there is no other station announcing RX attempts, then we could continue to try other modes.
Markus, we're running DFCW-180 in 11 mHz, not DFCW-90. This has proved to be the best combination, at least from my point of view.

Your table states that a detection in OP-32, using your correlation software, would result in a clear decode if the signal is as good as "M" copy in 11 mHz, right? What happens if there is QSB during that time? The events of > 30 minutes without QSB are quite rare i think. It looks like i have to use a kite antenna here on the building :-)

73, Stefan/DK7FC

Am 03.08.2013 13:47, schrieb Markus Vester:
Hi Edgar, LF,
 
this looks like a great project, and it's good to see a live grabber from VK7 again. So with that extra distance you might reach the top three in the DX list... unless Mike, Bob, or someone else takes the challenge and picks up Stefan in ZL ;-)
 
Orford - that's surely a nice location. On the occasion of attending a conference some 15 years ago, we were lucky enough to be able to drive around the Tasmanian east cost for a few days. We were much impressed by the beauty of the landscape, the clear skies, and the friendly and easygoing manner of the inhabitants.
 
Are Stefan and you intending to focus on DFCW only, or try other modes as well? Attached beneath is a short table, lining up approximate sensitivities for a few weak-signal options.
 
Best 73,
Markus (DF6NM)
 

Mode    norm.SNR SNR bandw. duration  remarks
          dBHz    dB   mHz   minutes
carrier   -18     14   0.4*   >30     highly significant peak in 0.4 mHz spectrum
DFCW-90   -12      6    11*    42     marginal "M" detection in spectogram
DFCW-90    -6     12    11*    42     fully readable "O"
Opera-32   -1      8   125     33     reliable decoding by Opera software
Opera-32  -12     21   0.5     33     correlation detection of a coherent transmission
WSPR-15    -4    3.5   180     15     decoding by WSPRX software
WSPR-30    -7    3.5    90     30     accelerated replay to WSPR software
MFSK37     -9     14   3.3*    25     visual decode or automated peak search
 
Notes:
- SNR thresholds are only approximate.
- SNR referenced to carrier power (not average).
- normalized SNR in 2.5 kHz can be obtained by subtracting 34 dB from dBHz.
* noise bandwidth is 1.5 times the stated FFT bin width. 
- duration to send "DK7FC" message (19 dashes and 4 spaces).
- MFSK37 is absolute frequency keying, sending one 5 minute dash per character.

From: edgar
Sent: Saturday, August 03, 2013 1:28 AM
Subject: LF: DK7FC Equinox reception

Hi,

During the last three Equinoxes I have attempted to receive DK7FC's
signal at QE37pd, Moonah, Tasmania.

The best result was achieved last April.

Refer to:
https://dl.dropboxusercontent.com/u/101251787/DK7FC%20reception.pdf

I decided for next Equinox period, (20th September 2013), that I would
attempt to better the distance previously achieved.

The results will be available on the internet.

https://dl.dropboxusercontent.com/u/101251787/testIDC.html

At present the equipment is set-up at QE37pd, and when possible Stefan
is running test transmissions from 19:00 to 22:00 UTC.

By the middle of August the system is to be set-up at Orford, on the
east coast of Tasmania, to operate until the end of September.

http://no.nonsense.ee/qthmap/?qth=QE37wk

The frequencies of DCF39 and HGA22 signals are also being monitored to
determine the propagation.

So I invite members to participate by monitoring the progress via the
web images.

Regards, Edgar
Moonah, Tasmania.

<Prev in Thread] Current Thread [Next in Thread>