Ham Radio - Decoding marine weather fax using FLdigi on HF

[@caulktel]

A bunch of us hams built Wefax decoders for the Radio Shack Color computer on a blank Rom pack boards. They worked so good that the NOAA office in the bay area thought we were lying to them when we showed them some near perfect printouts. It was lots of fun. Thanks for the video Kevin.

[@Jimwill01]

That was what I did too. Funny how many people kept asking my why I didn't get a "real computer" instead of a "game computer"! lol The coco did everything I wanted it to do at that time!

[@caulktel]

J. Williams Same here, I used my CoCo for everything, programmed EPROMs, used it for Packet radio, word processing, you name it. Oddly enough, I wasn’t into gaming and never used it for that. I even built a new computer from scratch that ran the same OS, keyboard and all. Did you subscribe to Rainbow magazine?

[@Jimwill01]

I did very little game playing on mine. Mostly learned Basic on it. I subscribed to some magazine, but I really can't remember if it was Rainbow or another one. I got the 16K model and did the piggyback memory upgrade. Lots of learning on that beast! LOL

[@astrorad2000]

my first computer was the Color Computer...i also did the piggy back memory upgrade and had a floppy drive eventually too...better than the cassette loader. Rainbow was the way to go...did RTTY with the CoCo on my ham rig too....73...WB9NYI

[@Brass735]

In the days of DOS, I monitored WEFAX through an MFJ1278B. I would sometimes print it. I haven't done that since Win 95. Good times. Thanks for the memories.

[@kytecit5653]

Kevin - Thanks for the video, helped me clean up my decode with the Noise filter. To correct the image slant, you may want to use the auto align toggle - which is just to the left of the Noise filter.

[@Dzonemp]

This was very informative. I don't have a transmitter, but i used to listen to my desktop radio and I've heard that sound many times. Thanks for clearing that up for me.

[@WilliamParmley]

Outstanding, thanks! For the people asking about how to send your SDR audio to another program, do a search for Virtual Audio Cable.

[@GeezerDust]

Watched the video - up and running receiving wefax with fldigi in abt 5 minutes. Good stuff. Tnx

[@travisd1000]

Just for correctness - NOAA provides the weather maps, but US Coast Guard actually handles the HF broadcasting. NOAA/NWS converts the images to the Fax audio format and hands off to USCG.

[@loughkb]

Thanks for clarifying Travis. When I get rolling on recording, I sometimes miss a detail or two.

[@dbingamon]

I remember receiving fax on a Commodore 64 back in the 80's. A little harder to view on 320x200 pixels.

[@oz1sej]

Great video! I just used it to receive my first weather fax from Northwood on 8040 kHz! :-)

[@watcherr1]

Right On ! Trying to master fldigi and this helps.

[@tlrptg]

for Europe, add the Pinneberg station, on 3855, 7880 and 13882.5 KHz in WEFAX576 mode.

[@kurtzFPV]

Very cool. Decoding some now for the first time. Appreciate the guidance.

[@RadioHamGuy]

Good info! I used to copy this once in a while, will have to give it a try again. 73

[@WHNorthcote]

If you have an Android phone there is a HF Wefax decoder. It's cheap and does start in auto mode. So if you are at the beach you can get information via fax using your cell phone also. When I do fax on Fldigi I put it 1.5Khz down and you get a nice white image. I set the center to 1500 and have audio from the station at 2000Hz and without fade it does give a clear white image.

[@jdmeaux]

Lots of great info there, Kevin.

[@cliffsirman6657]

Kevin, Great video! What antenna are you using for the SDR Dongle? Thanks!

[@GodzillaGoesGaga]

Kevin, that’s a great explanation. Could you possibly share all the setup info with your setup please. Maybe a simple tutorial on what you installed and what you need. I have rtl-Sdr but I assume you need an up converter and some form of audio pipe s/w fo fldigi ?

[@rogue_spirit]

I'm in the exact situation as you and I'll appreciate such a tutorial. I don't have an up converter to get AM broadcasts yet but for the meantime I downloaded a modified driver (from Oliver Jowett) for SDR# that does the same job but software side. It still needs a good antenna. You can find it here: www.rtl-sdr.com/rtl-sdr-direct-sampling-mode/ Other hardware solutions: www.rtl-sdr.com/direct-sampling-mode-hardware-modifcations/

[@loughkb]

I think I probably used the SDRplay for that video. For the RTL, you would need an upconverter, or one of those modified nooelec units that do direct sampling to get to the lower frequencies. As far as piping the audio, I run linux on everything and the way to do it there is to use a program called Pulse Audio Volume Control. You can use it to choose a source for a program that is "recording", choosing a monitor of the program that is "playing" will pipe it's audio through. Pretty easy. I'm not sure how you'd do it under windows, but I'm sure a search on windows piping audio between programs, would turn up a solution.

[@nobody1841]

Very straightforward presentation. Do you know if this application land based only? Or might it work offshore as well?

[@rogue_spirit]

It is mainly used by sea ships if I'm not mistaken. There are plenty of pictures online showing onboard fax devices getting such maps.

[@Jimwill01]

Great! Now if fldigi could do sstv! (or can it???)

[@loughkb]

No, it can't. If you're on windows, look for mmsstv. If you're on Linux, install QSSTV.

[@Jimwill01]

I am on both (linux and windows) and I have fldigi/flrig installed on both. I've use both mmsstv and qsstv. Managed to get some of the ISS photo's! :)

[@samglaim4274]

Interesting stuff :-) Thanks for the video

[@Digi4u]

Tnx for this video Kevin. Receiving wefax was one of my favourites back when I was a SWL late 80s early 90s, and still like to do this once in a while. To tune correctly to a wefax station, set your receiver 1.9 kHz lower than the listed frequency, and in USB ofcourse, so that the black frequency is at 1500 Hz, and the wite at 2300 Hz for a correct picture, although it does work when not tuned at 1.9 kHz, as you demonstrated. If you like to play with other fax software, I recommend JWX, a Java based software that really works well and on different platforms as well. You can find it here, along with some interesting theory about fax receiving: arachnoid.com/JWX/ Hope this is useful....73 ! Patrick ON4CDJ

[@loughkb]

Thanks for the additional info, I'll take a look at JWX. Yeah, I should have pointed out the 'proper' frequency tuning. I tune it a little lower to get the audio down more in the center of my radio's audio pass band. Just a little bit more signal to work with there.

[@AlGrantnz]

I dont see the LPM controls in my version of Fldigi? Should they be there in latest version? What do I click to start receiver when I hear the chirps?

[@loughkb]

It's been awhile, but as I recall, the decoder starts automatically once it recognizes the tones. I think you need to click on the waterfall and align the decoder with the signal. Put the right side red line on the sync pulse. Should look like a solid vertical line in the waterfall.

[@AlGrantnz]

@@loughkb I am missing the LPM row of boxes...

[@loughkb]

@@AlGrantnz I don't know what you mean by LPM boxes.

[@loughkb]

@@AlGrantnz Ok, I went and re-watched the video. That bar seems to have changed on the recent FLdigi. When I put it in wefax mode, right above the macro buttons is a single bar that starts with "Save APT CONT" and the rest of the controls for the wefax mode. I am running FLdigi 4.1.23

[@professormoptop]

@@loughkb my red slider on the newest version that is in the waterfall area keeps jumping out of the signal after being set. How do you fix this?

[@jackneff179]

do you puut the rcvr audio into the mic jack::::

[@loughkb]

You can, but you want to set the receiver to a very low volume level or you will overload the microphone pre-amp circuit and create distortion that makes decoding the signal hard.

[@karie0114]

I have HDSRD running with the frequency programed, but I don't know how to pump that data into FLdigi

[@loughkb]

Search for how to pipe audio between apps on windows. I only run linux.