The Australia Day long weekend has been a good excuse to get back to blogging about various “random” things with radiofax being the topic of choice this weekend. I had fond memories of an unexpected DX surprise one night in receiving GYA radiofax from Northwood, United Kingdom from Sydney, Australia. Back then, receiving such distant stations directly was a “magical” freak occurrence and rarely resulted in clear pictures. But there were a number of characteristics of GYA which made it noteworthy – the alternating white-black bands in the margins and the alternating striped “chirp” bar prior to the end of each page. I very much wanted to check in and receive such faxes from “up close”, hoping for some clean copy.
To do this, I enlisted the “help” of University of Twente’s WebSDR, the Wrexham KiwiSDR (borras2) in the United Kingdom and SK6AG SDR 2 in Groto, Sweden. With four frequencies listed, three active at any time and a claimed output power of 10kW, I was hoping for some good results.
The charts shown represent a snapshot in time of the charts issued by this station. The charts should not be used for navigation purposes and are not current or kept up to date. Copyright in the chart material belongs to the transmitting agency, which was not clearly identified on the charts but believed to be the UK Meterological Office. Charts are reproduced for documentary purposes to illustrate the technical aspects of the transmission, formatting of the content within the transmission and as proof of the activity status, propagation and reception of the signal on the dates and times noted.
I was able to observe transmissions on all listed frequencies except 2618.5kHz (possibly due to time), with best success on 4610kHz. However, it seems that GYA is no longer the same station that it once was, as over several days of observation, the content of the faxes did not match the listed schedule in the NOAA/NWS document. The alternating black-white margin and “chirp” bar are also gone, replaced by a rather “consistent” set of faxes repeated several times daily and no schedule that I could receive.
A typical fax is illustrated above – Sea Surface Temperature received 1400UTC on 20th January 2019. The chart has a standard amount of phasing area, slightly longer than usual stop-sequence and surprisingly almost zero image margin. As a result, it is quite annoying to receive as the horizontal alignment of the start point is critical if you wish for the chart to be easily readable from edge to edge. The charts are all “short” rather than “tall” orientation, requiring no rotation to read. The title is always in the top left corner, but unusually, no information about the issuing entity is provided on any of the charts received. The chart uses a mixture of dotted and solid lines.
Another chart which is transmitted is the Swell Height (metres) and Swell Direction. Note the spelling of “metres” which is distinctly British. Again, the chart bears no identification and has virtually zero margin area. Received 1348 UTC on 20th January 2019.
The 10m Wind chart is shown above with very similar features – very much a “consistent” product. Received 1312UTC on 20th January 2019.
The Precipitation (CrossDiag) and Visibility less than 5000m (Cross) chart uses two levels of shading to denote the areas of precipitation and low visibility. This is a rather interesting approach, as it does not take advantage of the “greyscale” capabilities of radiofax. Chart received 1224UTC on 20th January 2019.
The Surface Prognosis chart includes a Geostrophic wind scale in the bottom left corner. Received 1212 UTC on 20th January 2019.
The Surface Analysis chart follows the same convention, received 1200UTC on 20th January 2019.
Despite several days of monitoring across a number of SDRs and across several frequencies in parallel, only the above six products were received with no schedule information. There was also no test charts which might reveal the transmitting agency.
Unfortunately, it seems that the GYA I caught a glimpse of in the past has since disappeared, replaced by this rather consistent but almost characterless service. It’s a bit of a disappointment to me, as I was hoping to finally get a clear image of their schedule, QSL request card or even just to see the alternating black-white margins and chirp-bar again.
Despite this, GYA seems very easy to identify as every chart looks the same and it is the only station that I have heard that has practically zero margin area during the image period. That makes it rather unique.
I should be thankful that the frequencies are still active and the charts are still being sent – the worst thing that could happen is that it would be shut down entirely. Apparently, if the NOAA/NWS schedule is correct, GYA of the Persian Gulf is offline and my monitoring seems to confirm this. The time for radiofax services may indeed, be limited.