Friday, March 19, 2021

Fun With WEFAX

 Or WEather FACSimile transmissions by NOAA. There are of great use to mariners, as they provide weather charts and weather forecasts to mariners at sea, and away from VHF radio range. They transmit this data on several frequencies around 4MHz, 8MHz, and 10~12MHz. Back In The Day, it took specialized equipment, but these days all you need is an HF radio that tunes 3~30MHz, and a PC running some free software.

This NOAA satellite image came in tonight from the Pt. Reyes station on 8.682MHz:

The image is slanted because I haven't done this in a while, and forgot where the "Slant Adjust" software slider was.

Other images after I corrected the slant, which is caused by timing errors between the sending station and my soundcard.

This one is a chart of the barometric pressure through the area. The curvy white lines are called "Isobars" . They represent points of equal barometric pressure.

And they also broadcast wind vector charts. This picture is several strung together, as I forgot where the control was to keep each image separate.

While these charts aren't very much use to me in my landlocked location, they are nice for getting a "Long Range" view of the global weather.

After the weather warms up, I'm going to build an antenna for the 137MHz Automatic Picture Transmission satellites, which will give me near real-time satellite imagery of this area.


  1. That looks like a great deal of nerdly fun. Just the kind of stuff I might be doing one of these days. I seem to recall that you had a 137MHz setup in Torrance a while back.

    Being an Aviation veteran and a radio type, I enjoy looking at the GOES images daily to get a feel of what's in store for us.

  2. Yep, I used one of the "SDR Dongles" and it worked very well. I'll probably set up one of the mini-PCs I have to just do the weather stuff.

    The GOES birds are up around 1690MHz. I've got a 1 Meter offset-fed dish I could use, but I'd have to make a feed, and gin together a downconverter.

  3. I served as a Weather Forecaster from 1984 until 2010. All but 4 years of that time was doing Army support. 80s and 90s relied on these broadcasts. The Standard AF equipment was the 9315 TR-T and it worked very well (once we got a good signal) but it was large and heavy for a very mobile Special Forces unit. In the 90's we started working with the radio intercept hardware and software that would make the laptop the replacement for the 9315. We had it up and running in time for the beginning deployments after 911. Considering how bad Comms were in 01,02 and 03 these were essential. Then Comms improved dramatically and no one used them (the 9315's or the laptop versions) by 05.

    MSG Grumpy

    1. I don't remember what they used for a decoder/printer on the Iowa, but we had an R-1051 HF receiver in the weather office, connected to a dedicated antenna.

  4. Point Reyes has a lot of radio history. Check out the Maritime Radio Historical Society website. For True Believers everywhere:

    1. Yes, I listen to them when the send CW from the former KPH radio site.

  5. give you that and more...unless it is just the Geekery of getting it the way you are that appeals....(Not that I don't appreciate the Geekery for it's own sake).

    1. Mostly for the Geekery, but also to have a back-up for various reasons.

  6. Late to the party...

    In the 1980s I fished commercially. When part of the 'Midway fleet', ranging the entirety of the N. Pacific north of Hawaii, on the search for Albacore, we used a fax to get our wx. B&W we got only the first image shown here (satellite cloud coverage) and a textual description in raw format (not plain language). I forget the HF freqs we used. But we were duly licensed to transmit also.

    Sometimes for a different source of wx data, but mostly for comms, we'd illegally piggy back on a Japanese AM station. One would only be caught if the station went down such as for maintenance. I seem to remember that two boats were caught when the station did indeed go down. Knowing broadcast scheduling is important it seems.

    As an aviator, I much prefer the raw data. I have noticed that the push for plain language (less need to know the code and symbols) there is also a 'dumbing down' of the data; that important details are omitted. The trend seems to be more towards a general synopsis which reminds me of The Weather Channel, which I abhor.


Keep it civil, please....

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