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RTTY-HF-RTL-SDR
#1
Photo 
Hi,


finaly today I got my first RTTY HF reception.
Transmitting from Hamburg in Germany to Alicante in Spain

Here the result:

   

They offer weather for the Atlantik, North-Sea, Baltic and East/West Mediteranean

The Programm/Times and frequencies you can find here:

Prog1
https://www.dwd.de/EN/specialusers/shipp...onFile&v=1

Prog2
https://www.dwd.de/EN/specialusers/shipp...onFile&v=1


I used:
Pi 4
OP2
RTL-SDR- wide with HF connected to my Backstay-Antenna
GQRX (Installed with OP2 SDR-VHF Installer)
FLDIGI installd over command line


The steps were,
1: to get an FM-Radio station to play in GQRX
2: Tune in an HF-Signal like RTTY or Weatherfax in GQRX
3: Get FLDIGI to decode an Weatherfax from an audio (wav) file
4: Get the HF-Signal from GQRX into FLDIGI
5: Find the right Settings for RTTY-Mode on FLDIGI

At the end it was a lot of trying and testing and I´m still not verry shure how to reproduce ...

From this point it should be a short stepp to get Weatherfax decoded, also my harbour with all the
Masts and Mountain is not a good palce to receive.

Save sailing to all

Andreas
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#2
thanks! an openplotter-hf app is in the TODO list
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#3
(2020-11-09, 07:08 PM)Sailoog Wrote: thanks! an openplotter-hf app is in the TODO list

Now I manage to capture with OP2 Navtex and Weatherfax:

   
   
   

The main problem I found was to get the GQRX-audio-stream into the FLDIG decoding program.
I don´t understand much about the PI audio settings but it seem that the OP-SDR-VHF settings are not
the ones the HF situation requires. (Alsa, Pulseaudio, .asoundrc). I finaly uninstald in OP SDR-VHF with the
AIS and GQRX and installed GNURADIO and GQRX over the command line.
I guess a SRD-HF for OP will sort this out.

Otherwise it is working nicely. The CPU ussage is low. Runnig the PI, OP with Signalk , the GQRX and FLDIGI consumes
only about 40-45% of CPU and 25-30% if the windows are minimized. CPU Temperature arround 60C in about 23 C ambient temerature. So it would be no problem to run in the background ....

By the way I did not get Sean Weaterfax-Plugin in OPENCPN to run, also a problem off getting the audio setup correctly.

Would love to have an OP-HF-APP .... maby this is some more motivation.

Thanks a lot for everybody who has contributed to this great project.
Save sailing 
Andreas
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#4
@xfactor99
small question. Which SDR Receiver, that RTTY (147kHz) & NAVTEX(490/518kHz) , do you use?
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#5
(2020-11-13, 11:19 PM)BlackSea Wrote: @xfactor99
small question. Which SDR Receiver, that RTTY (147kHz) & NAVTEX(490/518kHz) , do you use?
Hi Black Sea
it is a Patrol Dx SDR wich I own fo a cupple of years so it is an early version. Here you can see:

https://www.rtl-sdr.com/tag/dx-patrol/

Just google, but I think they are all Chinies 100kHz - 30 mMz wide rtl sdr (with an downconverter) . You find the them for arround 30€.
The RTTY above i made on 7.646 kHz. as i think the 147kHz will not find all the way to Spain but not shure about.
Save sailing
Andress
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