WEFAX
WEFAX
(Parent page: Radio)
- What is WEFAX?
- Reception and frequencies
- Decoding using a PC
- Decoding using an iPhone
- JMH: 3622.5 kHz (USB 3620.6 kHz)
- JMH2: 7795 kHz (USB 7793.1 kHz)
- JMH4: 13988.5 kHz (USB 13986.6 kHz)
- Origin: I'm not certain. Is it Tokyo? Kagoshima? Here are some images I received on Demcember 8, 2025 on 13988.5 kHz: (JMH)
- Frequency: 16971 kHz (USB 16969.1 kHz)
- Origin: Tokyo?
- Frequency 1: 7433.5 kHz (USB 7431.6 kHz)
- Frequency 2: 9165 kHz (USB 9163.1 kHz)
- Frequency 3: 13570 kHz (USB 13568.1 kHz)
- Origin: Seoul (South Korea) The station also transmits on 5857.5, but I have not been able to hear it so far. I seem to get best results on 13570 kHz.
- WEFAX Reception : WEFAX is a system to transmit imags (such as weather charts) over the radio without using much bandwidth. A PC with a simple USB sound card can decode and display those tranmissions. : From Japan, I was of course able to receive images from Japan, but also from Korea, China, Hawaii and even as far as Australia.
- BroadCast Listening (BCL) : The pleasure of attempting to hear a great number of stations and collect QSL cards.
What is WEFAX?
WEFAX ("weather fax") is a radio fax transmission service intended for use by ships and boats. Transmissions usually include various sea maps (currents, forcasts, etc) and sattelite photos.
Dedicated and professional reception equipment of course exist, but a simple PC with a sound card can also be used. Ideally the radio audio output should be wired directly to the PC sound input, but using a microphone next to the radio also works, however surrounding sounds will add noise to the final image.
For the technical details of how WEFAX works, I recommend the Radiofax Wikipedia page.
Weather fax services are likely to eventually completely disappear, many countries have in fact already ceased broadcasting. That's too bad, I just missed (two years!) the end of the New Zealand ZKLF service (ended in 2023). With luck I could have managed to receive images...
Now is a good time to try receiving everything I can before stations forever disappear!
Reception and frequencies
The weatherfax.com website is an excellent guide to the stations available in different corners of the world and their respective schedules. To receive a station, the receiver must be in SSB-USB mode (upper side band) and tuned to a frequency 1.9 kHz below the published center frequency.
JMH (Weather fax - Japan)
Being located in Japan, receiving the Japanese JMH station frequencies was the obvious first step.
Satellite photo
Satellite photo
Weather chart
Weather chart The JMH broadcast schedule is available here: https://www.jma-net.go.jp/common/177jmh/JMH-JPN.pdf (in japanese)
JJC (Kyodo News - Japan)
Kyodo News still broadcasts a newspaper in japanese (and reportedly, english too) on shortwave for ships at sea! This might very well be the last service of the type in the world! I find this extremely fascinating! Transmission is done at 60 lines per minute instead of the usual 120 for weather charts. This is most likely to increase legibility of the compact japanese characters.
Excerpt from a newspaper received on 2025-12-11
Excerpt from a newspaper received on 2025-12-11
HLL2 (Weather charts - Seoul)
Image received on 2025-12-10 from 13570 kHz
Image received on 2025-12-10 from 13570 kHz
Asia surface pressure 2025-12-31 from 9165 kHz
Asia surface pressure 2025-12-31 from 9165 kHz
XSG (Weather charts - Shanghai)
| Station | Frequency | Origin | Received | | ------- | --------------------------- | ---------------- | ---------- | | XSG | 12382 kHz (USB 12380.1 kHz) | Shanghai (Chine) | 2025-12-10 | | XSG | 16559 kHz (USB 16557.1 kHz) | Shanghai (Chine) | 2025-12-10 |
48H WAVE HEIGHT FORECAST
48H WAVE HEIGHT FORECAST
KVM70 (Weather charts - Hawaii)
| Station | Frequency | Origin | Received | | ------- | --------------------------- | ------------ | ---------- | | KVM70 | 11090 kHz (USB 11088.1 kHz) | Hawaii (USA) | 2025-12-30 |
24HR WIND(KT)/WAVE(M) FORECAST
24HR WIND(KT)/WAVE(M) FORECAST
048 HR WAVE PERIOD FCST/DIRECTION
048 HR WAVE PERIOD FCST/DIRECTION
The title of the charts above was difficult to read so I compared them to the files available online to identify them correctly. Northeast Pacific Weather Briefing Package
VMC (Australia)
| Station | Frequency | Origin | Recived | | ------- | --------------------------- | --------------------- | ---------- | | VMC | 11030 kHz (USB 11028.1 kHz) | Charleville, Autralie | 2025-12-30 |
The signal was very weak, but I recognize the shape of Autralia and its north-west surroundings.
Image received on 2025-12-30
Image received on 2025-12-30
Decoding using a PC
I use Fldigi which can (among many other things) decode WEFAX transmissions and automatically create PNG files. I can just leave this software running and come back later with a bunch of files in the target folder.
Reception in progress with Fldigi
Reception in progress with Fldigi Conditions where very good while receiving the above, but this is not always the case. When there are interferences or noise due to a weak signal, the image quality quickly drops:
Noisy reception
Noisy reception Depending on the day (or the time) conditions can change, leading bad reception. Switching frequency can help in some cases. With my setup during the day, I tend to get better results with high frequencies. Here is an example where I switched frequency when an image was being received from HLL2:
Receiving different frequencies from a given station
Receiving different frequencies from a given station
One should make sure the audio signal does not get distorted. The input volume should be as high as possible, but without clipping. Fldigi has a level indicator which should be green (occasinally yellow is fine) but never red!
Decoding using an iPhone
There are also apps such as "HF FAX" which can decode fax transmissions but I find that Fldigi on a PC is easier to use.
Other pages
This page is part of Radio. Other pages in this section: