RTL-SDR for Marine HF Weather Fax
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- เผยแพร่เมื่อ 2 ต.ค. 2024
- Up to date weather information is critical for sailors and can make the difference between a safe or a hazardous passage. Marine HF Weather Fax has been working reliably for many years and is an independent source of valuable information. NOAA’s Marine Weather Fax page has all the information you need to use this resource. The instructional video from Jordan at Project Atticus is excellent and covers all the basics to get you started. In this post I will review the Frequency Schedules, basic HF receiver equipment, and free software programs that can be used to decode the received signals. See Blog Post for all links.
Blog Post:
jeremyclark.ca...
SDR# Settings:
FreqShift=-125.0MHz (if using Nano Upconverter)
USB=SchedFreq-1.9KHz, tune for Blk/White on FLDIGI Red Marker Edges
Gain only as much as required no more, to avoid overload
SoundCardOpt to StereoMixer or Virtual Audio Cable
FLDIGI Settings:
Mode=WEFAX IOC576/120Line
SoundCard/PortAudio/Capture Virtual Audio Cable
Adjust tones to fall on edges Red Cursor
HF-WEFAX Scicos Simulation:
jeremy-clark.c...
HF Telecom Learn by Simulation Short Form pdf:
jeremy-clark.c...
If you buy a rtl-sdr unit with two antenna in plugs, the second one capable of 100kHz to 30Mhz, you don't need any up-converter. In the settings for the hardware, you might eventually need to add "rtl=0,direct_samp=3" in the text field or device string (Gqrx). .... And with that you also don't need any extra USB power plug.
Edit: In my case receiving W-Fax at 7.878 MHz.
The RTL's that go down to 100KHz sample at 28.8Msps, so if you don't mind aliasing about 14.4MHz then no problem.
I was just wondering if you ever had a problem when using FL-Digi.. (Shifting) the Weather Map as it Receives.. I am Experiencing a problem with the alignment that shifts the map with either SDR# (Very bad).. SDR++ (not as much or as bad) but still does it.. Would you have an Idea as to Why : See and example of this problem th-cam.com/video/C_vcrq-XW0M/w-d-xo.html
It is tricky decoding WxFax. Try Multipsk they just updated their apt decoder.
Is there a place where you published, in detail, your settings for both SD# and FLdigi, so that mine would run as yours does in the video? BTW, i have the Up-converter as well, so now its software settings that needs help. de W7WXX
Mic I will put the major settings below the video. I also made a short simulation showing the setup with black=1500Hz & PkWhite=2300Hz. The key is to tune in USB mode about 2KHz below the listed frequency. Then adjust up/down in small increments so that the black/white tones line up with the edges of the FLDIGI red cursor. Be careful with too much gain on the RTL, the noise floor/intermod comes up rapidly. 73/JC VE3PKC
Very good stuff Jeremy! Thanks for posting the video and all the good information. I had the chance to try this out this morning entirely based on your video. Had some success, but need to work on my antenna/receive situation with the 'ol RTL-SDR.com blog unit. Keep up the good work! 👍📻🌦⚡🌍
Thanks Good Luck!
Great information, thank you.
Glad it was helpful!