Radiofax: NMC Pt. Reyes California (National Weather Service/NOAA, USA)

Given that the United States of America’s National Weather Service (NWS) / National Oceanic and Atmospheric Administration (NOAA) operate a large number of the remaining radiofax stations, it’s about time I covered another from the family. Previously, I covered KVM70 in Hawaii. This time, I look at NMC, stationed at Point Reyes, California in the continental US.

NMC transmits on four of five frequencies (4346, 8682, 12786, 17151.2, 22527kHz) at any time at 4kW power. Like many other of the stations within the family, many charts are repeated and there is satellite imagery within the schedule.

In the hopes of receiving better quality charts (as with DWD), I chose to use the KiwiSDR at KPH, a former marine coastal radio station due to its geographical proximity as well as its fairly good antenna performance based on some prior “tuning about”. Unfortunately, as the faxes will show, propagation still seems to be a factor.

As usual, the charts are received at an instant in time and are not updated. As a result, they do not reflect the current condition and should not be used for navigation purposes. Copyright of the faxed material belongs to the transmitting agency, the National Weather Service and the National Oceanic and Atmospheric Administration of the United States of America. Faxes are reproduced for documentary purposes for examination of the transmission characteristics, formatting of content and as proof of reception, station activity and propagation at the times and dates listed. Up-to-date charts can be downloaded from NOAA at http://tgftp.nws.noaa.gov/fax/marine.shtml.

Faxes

Faxes were received via the KPH KiwiSDR on 19th through 21st January 2019. Reception was predominantly via the 12786kHz frequency which provided the best signal around the clock. Faxes are separated into categories for easier viewing.

System-related

The first chart in this category is a short CQ by radiofax. While it is an unusual thing to do and something I’ve really only see the USA stations do, it does illustrate the presence of black-margins and some form of data encoding in the first few image lines. The CQ is formatted differently to that of KVM70, being easily readable using the call letters of the station, but also featuring the logos of NOAA and USCG. This example was received 20th January 2019 at 1120UTC, however, such “test charts” are regularly transmitted throughout the day – three times a day in the case of NMC. Phasing, start and stop tones appear to be standard.

The schedule is the next chart in this category, with the full schedule broken up into two “short” faxes. The schedule itself was last modified 19th September 2018 with the addition of new products resulting in the schedule taking a bit of a strange appearance with some sections sharp and other sections blurry (as if processed as an image). This example was received 1124UTC on 20th January 2019.

The second portion of the schedule was received 1135UTC. Unlike KVM70, the schedule does not take up the full width of the fax and the font is not all monospaced font.

NMF also seems to invite comments – this notice from 24th October 2016, received 1146UTC. On the whole, the text is bold and readable and the chart is a short form chart which seems to be the default.

There is also a product notice, received 1157UTC which contains information about other services and changes to services. I wasn’t aware that NMC operates SITOR and HF Voice – perhaps I should go trying to receive them someday.

Of interest is that during the monitoring period, there were no instances of product discontinuation messages, nor of chart being unavailable. No runt faxes were received either, which is great.

Satellite Imagery

A total of three different satellite images are disseminated, this being an example of the NE Pacific GOES IR image received 1403UTC on 20th January 2019. The almost square image does not take up the full width of the page and is bordered by black bands. It takes advantage of the greyscale capabilities of the radiofax medium.

This fax was received 0737UTC in 21st January 2019 and is the Tropical GOES IR image. It takes the full width of the fax, but is bordered by black bands top and bottom.

The above image is an example of the Pacific GOES IR image and uses the full width of the fax, bordered by some black bands on the bottom only. This was received 0908UTC on 21st January 2019.

Surface Analysis

The main surface analysis products are sent from 0305UTC, the above being an example received 19th January 2019. This is labelled the Preliminary Surface Analysis – Part 1 (NE Pacific). The chart is sent sideways, occupying the full width, with the labelling in the top left.

The second part is sent 0318UTC, also a short chart with the labelling in the bottom left. This was observed with KVM70, however, this is the Preliminary Surface Analysis – Part 2 (NW Pacific).

Unlike the other stations, this is followed at 0331UTC and 0344UTC by the “final” versions of the two – I don’t see much of a difference except for the labelled times of issue.

At 0245UTC, the 500mbar analysis is sent, which is a short chart with the NWS/NCEP credited. Interestingly, this is labeled as a 0-hour forecast … which basically means it’s an analysis.

At 0255UTC, there is the sea state analysis chart in meters. I do like how NOAA charts are very consistent and use bold thick lines for ease of reading in poor signal conditions.

There is a tropical sea state analysis at 0205UTC. This one doesn’t quite use up the full width of the chart but is very legible. Note this one is in feet!

This chart was received at 1852UTC and is one SST analysis. Unfortunately, I wasn’t able to receive this one better but it appears very sparse and looks to be based on POES data.

Likewise another SST analysis at 1902UTC received in much the same bad shape.

There is a tropical surface analysis which is the “right way up”, with a lot of white space on all sides. This is very similar to what we received from Hawaii, including the logo obscuring some text. The above example from 0945UTC on 21st January 2019.

There is a chart which looks to originally have been a “tall” chart rotated to become a short chart – the Cyclone Danger Area/High Wind/Waves chart, received 1009UTC on 21st January 2019.

Surface Forecasts

The 24-hour surface forecast is sent a number of times, this example from 0758UTC on 21st January 2019. The chart is sent “sideways” as a short chart.

The 48-hour surface forecast is sent in the normal orientation as a short chart. The above example from 0828UTC on 21st January 2019.

The 72-hour surface forecast follows the same format, the above example from 2053UTC on 20th January 2019.

The 96-hour surface forecast also follows the same format. This example from 0707UTC rebroadcast on 21st January 2019.

Additionally, there is a 48-hour tropical surface forecast, from 0215UTC on 19th January 2019.

The 24-hour 500MB forecast is received at 0818UTC on 21st January 2019.

The 48-hour 500MB forecast is received at 0848UTC.

The 96-hour 500MB forecast is received 1953UTC – this example from 19th January 2019 with fairly poor results possibly due to multipath spreading of the signal.

Wind/Wave Analysis & Wave Period/Swell Direction

The main wind/wave analysis is transmitted at 0748UTC, this example from 21st January 2019 from NWS/NCEP.

The 48-hour wave period forecast and swell direction was received 0858UTC on 21st January 2019. The chart is the right way up and utilises the full width.

The 96-hour chart follows the same conventions, received on its rebroadcast at 0727UTC.

There is a Tropical 48 hour Wave Period/Swell Direction chart, this example from 1228UTC on 20th January 2019. The chart data is approximately square, but does not occupy the full width, flanked by white margins either side.

The 72 hour version is transmitted 2356UTC, this example showing poor reception with multi-path and weak signals.

Wind/Wave Forecast

As with the analyses above, it seems the 24 hour chart is sent rotated. The above is the 24-hour Wind and Wave Forecast in Feet, received 0808UTC on 21st January 2019.

Like the others, the 48-h and above versions are sent full-width. This example from 0838UTC.

The 72-h version is sent at 2103UTC, suffering from poor propagation but visibly sharing the same conventions.

Finally, the 96-h version as received on the 0717UTC rebroadcast.

The tropical versions of the above follow their own conventions that do not fill the full width of the fax. The above is the 24-hour tropical wind/wave height forecast, received 0959UTC on 21st January 2019.

The 48 hour version received 1208UTC on 20th January 2019.

Finally, the 72 hour version received 0235UTC on 19th January 2019.

Conclusion

As the faxes show, the NWS/NOAA family of transmitters have a vast number of similarities, sharing some charts, the black margins in the image period and the data “dots” at the top left. Where it differs is in some of the system-related fax content – the CQ is much more appealing, decorated with the organisational logos, and the schedule is formatted in a more modern way compared to that of KVM70.

That is not all however, as there are still a number of NWS/NOAA family stations to look forward to including Kodiak, Alaska (NOJ), New Orleans, Louisiana (NMG) and Boston, Massachusetts (NMF), as well as faxes from South Korea (HLL2) and Australia (VMC/VMW) when our local system resumes normal operation. All of that is to come in future postings (time permitting).

About lui_gough

I'm a bit of a nut for electronics, computing, photography, radio, satellite and other technical hobbies. Click for more about me!
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