As a case of last of the era, radio station JJC in Japan and 9VF in Singapore operated by Kyodo News in Japan is the last marine weather fax station which faxes daily news and navigational warnings. It is especially surprising since it is not affiliated with the meteorological agency – they operate their own fax stations starting with JMH.
One of the most important resources for those looking to receive radiofax is the list of transmission frequencies available from this guide written by the National Oceanographic and Atmospheric Administration (NOAA) of the US. This guide is regularly updated where information is available – and lists the carrier frequency (i.e. transmission centre frequency) for many fax stations around the world.
JJC and 9VF (on page 16) is listed with the following centre frequencies (tune to 1.9khz below in USB mode for white frequency at 2300hz and black frequency 1500hz):
- 4316khz at 5kW
- 8467.5khz at 10kW
- 12745.5khz at 15kW
- 16971khz at 15kW
- 17069.6khz at 15kW
- 22542khz at 15kW
- 16035khz at 10kW
- 17430khz at 10kW
The information is dated from 1999 – a long time ago – and I have reason to believe that the information may be incorrect. Radiofax services have been dwindling year-on-year, and surveys are held each year to try and gauge whether it’s worthwhile to continue operating such services. The frequencies above in bold are the ones which I have been able to hear the transmission on, although not necessarily decode a visible image.
The other frequencies which have not been bolded may be in operation, but propagation has not been favourable enough to my receiver to produce any sign of the signal.
Kyodo has a very specific signal – the slant factor in Fldigi is 0.004 for my sound card, compared to 0.012-0.015 for most other fax services, showing significant offset. The signal is transmitted in IOC576 mode with 60LPM speed (i.e. half the speed of most other fax services, taking one second per line of 1809 pixels). Faxes take hours to transmit at this rate, but at least it ensures a better quality for the delicate Japanese characters which are transmitted.
The signal transmits white tone for a while before a fax as a tuning signal, which then develops black pips which line up with the sync bar for almost a minute before the transmission. The start tone is prolonged, about five seconds, followed by regular polarity sync and then image transmission. The sync margin during the image period is black, which is inverted from the regular polarity where the sync margin is white.
So over the past few days, I’ve received a few faxes which are fairly “degraded” for quality – luckily as it is analog, it is possible to receive something even at low SNRs (~1-10dB), even if it’s just the sync margin.
In the case of fax transmissions, clarity is impacted by the signal to noise ratio, as well as the doppler multipath spreading of the signal which causes blurring at the edges and sometimes wavy/shifted faxes. As 1809 pixels are transmitted in one second (for 60LPM), a one pixel shift corresponds to a doppler multipath shift of 0.55ms which corresponds to a multipath distance at the speed of light of just ~166km!
For comparison, the distance by straight line from Tokyo to Sydney is 7822km, so the pixel time is about 2.1% path variation. Unfortunately due to the unpredictable behaviour of the propagation and height of the ionosphere, there is fading, sometimes deep and frequency selective causing horizontal noise bands, and multipath fades causing vertical lines to be doubled or jittery.
Of course, for the intended purposes of the signal, this should not be a problem, as it is intended to serve within its NAVAREA. While we are a neighbouring NAVAREA, that is no guarantee that the signal is receivable.
So here are some faxes:
27th January 2013 – JJC 22542khz ending 1956EDT (UTC+11)
27th January 2013 – JJC 22542khz ending 2040EDT (UTC+11) Sumo Match News.
27th January 2013 – 9VF 16035khz ending 2122EDT (UTC+11) Kyodo [?] News.
27th January 2013 – 9VF 16035khz ending 2226EDT (UTC+11) – missed the beginning because I didn’t have Fldigi’s non-stop mode activated, and it lost correlation. Kyodo News.
27th January 2013 – JJC 12745.5khz ending 2257EDT (UTC+11) Navigational Warnings – tuning tone, pre-sync pips, start tone, phasing visible.
28th January 2013 – JJC 22542khz ending 1824EDT (UTC+11) Fishing Chart (partial).
28th January 2013 – 9VF 16035khz ending 1824EDT (UTC+11) Kaiun-Suisan News (interrupted – Fldigi decided to “freeze” for a bit, don’t know why). In this transmission, you can just barely detect the beginning of the fax, and then the sync margins become clearer, and then the signal fluctuates … vertical banding is local interference.
And just for clarification, no, unfortunately I cannot read Japanese … but I do enjoy watching the propagation conditions visually judging by the image of the fax – and I do enjoy DXing signals, even though I’m in a noisy built up area. I had attempted to make contact with Kyodo before for QSL but unsuccessfully – so I am trying again. I would enjoy it more if I was in a radio background-quiet area ..
In 2010, I went to my Dad’s place – and using just a longwire, achieved much much better results (using MultiPSK for decoding as well). There’s no way I can do the same at my Mum’s place – even using a magnetic loop antenna to reduce interference!
Thanks for the info…. excellent copy…. been wondering if KYODO was still active and lost the freqs, so will now be looking again,…. qth is southern UK.
Thanks very much for your comment. i’m glad this information has been useful. DXing this station from the UK may be a formidable challenge – best of luck, and let us know how it goes. 🙂
I have copied KYODO news in the UK a few years back… when conditions/propogation/sunspot cycle was good… but not recently… I now use SEATTY, which I find is better than Multipsk, as you can adjust the page postion on live reception…. slant correction requires a STOP receiving but is very quick, so you can start again after only a few lines loss…. Registration makes it worthwhile. !.
Aerial I used was 66ft long wire at about 25ft agl… 200ft asl 15 miles from the coast. similar situation now. so will be listening out…. Copied Boston on 12750kcs at 2100GMT tonight, but was not very clear, and faded out quite soon.
If you’re willing, give Fldigi a go. It allows for on the fly slant correction factor change and image shifting as well – performance in greyscale is similar to MultiPSK. Fldigi receives all 1809px wide images without needing registration like MultiPSK as Fldigi is open source and free.
You must have quite a bit of room for such a longwire! I did manage something of that length in 2010 – hence the good copy on Kyodo, but now living in a very tight townhouse complex, my choices are either 6m longwire (not very long at all) or my Wellbrook Loop (in general, much better as it cuts through the S9+ QRM in this area). With my longwire, I did manage to catch Enviro Canada faxes back in 2010 – http://goughlui.com/legacy/hffax/index.htm
That’s probably my best DX aside from receiving GYA Northwood (once, never repeated), albiet very very noisy!
JVComm works better than fldigi/seatty in my experience,especially auto start/stop is working much better
hai lui gough…how to receive radio fax on my DVB SDR dongle? (22-1700Mhz)or please tell me ur receiver model number.
thank you
Most Radiofax occurs in HF bands between 2-28 Mhz, and cannot be directly received by an SDR dongle. In strong signal areas, doing the “direct conversion receiver” modification might be possible, but unlikely to yield good results as it is vulnerable to FM interference and low sensitivity (yes, I tried it myself but did not post any information about it).
There are some commercially available upconverter products which will convert this range of frequencies into something the RTL-SDR dongles can receive, but I haven’t tried any myself.
You should use a shortwave receiver or HF communication receiver with single side band (SSB) mode. AM only receivers are not suitable for use with Radiofax. A computer with a sound card running MultiPSK, Fldigi or Skysweeper is able to decode the tones into an image provided the sound card is decently calibrated.
I have used a rather expensive SDR, the Winradio G31DDC, to receive some faxes, and others with my older conventional Icom IC-R75. My first attempts with an Icom IC-R20 and Degen DE1103 were fairly poor due to strong local noise and low sensitivity.
You should experiment to find what works best for you.
– Gough
Ok thank you lui. i will buy up converter ..Broadcast Date/Time? (UTC)
The only source of schedule that I know of for this station is the NOAA Radiofax Frequency Schedules at http://www.nws.noaa.gov/os/marine/rfax.pdf
Note that some of the information is out of date or incorrect, but I’ve never been able to receive the schedule for JJC from the air as propagation to Australia is poor except for some hours of the night. You’ll have to spend some time monitoring, but for initial setup, it’s probably sufficient to choose a station closer to you first to see if it works.
– Gough
ok i will try
It appears Kyodo is now QRT – no longer transmitting.
If this is true, it’s rather sad but not entirely unexpected. It was the last newspaper-by-HF-fax service on the air. Many HF weather fax services, even today, are continually being re-evaluated for shut down due to high cost of operation and difficulty in acquiring spare parts for ageing transmitters. Mariners are frequently opting for HF-radio modems to download their weather data, or use of satellite broadband where cost effective.
I will see if I have the time to monitor the frequencies to be sure of their status …
Thanks for the update.
– Gough
Looks like that’s not true – I am seeing the signal on 12745.5khz at 1130UTC on my SDR’s waterfall (i.e. right now). Its probably still alive, although weak from my location.
– Gough
EDIT: Another start tone and phasing set were seen at 1200 UTC. This was preceeded by negative syncs for about two minutes which is a Kyodo specialty. Transmission is still 60LPM which POSITIVELY identifies it as Kyodo (as nobody else I have heard on air uses this mode).
And today, 20 September, 2014, I’ve received the Kyodo/JSC news bulletins on 16.971MHz and 17.430MHz, and a Japan Meteorological Agency weather bulletin for shipping on 22.542MHz and 16.971MHz.
Both were crystal clear … I’m in Tokyo.
I should add, Kyodo was 60 lines per minute at 0.004 slant, and the weather charts were sent at 120 lpm at 0.013 slant.
Thank you for the report and confirmation. Always good to have someone near the transmissions confirming their presence. Slant values can differ depending on your system and sound card clock, but might serve as a good starting point for new service users.
– Gough