How to decode maritime broadcasts in RTTY, Sitor B, and NAVTEX

(Photo Credit: NOAA)

(Photo Credit: NOAA)

Many thanks to SWLing Post contributor, Mario Filippi (N2HUN) for the following guest post:


Maritime Broadcasts in RTTY, Sitor B, and NAVTEX.

By Mario Filippi, N2HUN

(All photos below are courtesy of the author. Click each image to enlarge.)

Non-voice high seas weather broadcasts and safety messages to mariners can be found by spinning your VFO dial to 8.472 MHz USB courtesy of WLO from Mobile, AL, which provides these transmissions continuously. Here on the East Coast it is received with regularity due to it’s strong signal.

Those of you who are neophytes to RTTY or just want to dabble then this is the place to be to try your hand at an old and venerable digital mode. The RTTY (RadioTeleTYpe) parameters used by WLO transmissions are 45.45 bauds, 170Hz shift. These are most commonly used by amateur radio ops too. If you’ve roamed the bands for RTTY signals you’ll find that most are encrypted with a few exceptions, one of which is WLO which is transmitting continuously.

Tabletop SW radio set to WLO; SignaLink USB links radio to computer for decoding.

Tabletop SW radio set to WLO; SignaLink USB links radio to computer for decoding.

On 8.472 MHz you’ll receive weather information from different latitude/longitudes, along with other pertinent information to mariners such as high seas pirates (not radio pirates!) and naval maneuver areas that are important for ships to avoid. It makes for interesting copy.

To decode RTTY signals you’ll need a shortwave receiver with a BFO (Beat Frequency Oscillator), a way to pipe your radio’s audio into your computer’s sound card, and decoding software. There are several RTTY software packages out there, free, and my favorite is MMTTY. More info on MMTTY is at: http://hamsoft.ca/pages/mmtty.php . Old timers will find this software a snap to use, but newcomers will have to fiddle with the controls to get the decoding going. Below is a snapshot of MMTTY decoding a typical weather broadcast.

MMTTY dashboard with WX info. Cross-like indicator on upper right aids in tuning signal.

MMTTY dashboard with WX info. Cross-like indicator on upper right aids in tuning signal.

Another software available for decoding RTTY is Fldigi. Again, you’ll have to input the correct RTTY parameters such as baud rate and shift into the program along with adjusting your VFO carefully. It takes practice, but when the decoding is successful you’ll see Fldigi doing it’s thing as shown below. Both MMTTY and Fldigi have waterfalls displaying a visual image of the received signal. With practice you’ll be able to distinguish the different common RTTY shifts just by looking at the waterfall.

Fldigi in action with split screen; RTTY text above, waterfall below.

Fldigi in action with split screen; RTTY text above, waterfall below.

Now to Sitor B (Simplex Teletype Over Radio Mode B), another non-voice mode we can use to decode WLO transmissions. Sitor B sounds a lot like RTTY to the human ear, but requires different decoding software. WLO transmits weather information via Sitor B immediately after RTTY transmissions, switching back and forth, which makes for even more fun! Software that decodes Sitor B is available on the ‘Net as free downloads. One is MultiPSK, the other is YaND.

I like YaND (Yet another Navtex Decoder) which is used to decode NAVTEX (Navigational Telex) transmissions commonly found on 490 KHz and 518 KHz, but it works well for decoding Sitor B. There is a difference in the way messages are processed in NAVTEX versus Sitor B and for further information perform a Google search. But the fastest and easiest way to decode Sitor B transmissions from WLO is to fire up YaND. Below is a recent NAVTEX HF broadcast capture.

WLO HF WX broadcast for NE Gulf on 1/18/16 .

WLO HF WX broadcast for NE Gulf on 1/18/16 .

Well, hopefully some of you will be inspired to check out maritime weather/safety information found on WLO using RTTY/Sitor B/NAVTEX software. However, RTTY can also be found on the ham bands and on shortwave frequencies. Several RTTY stations from Germany are found on frequencies such as 11.039MHz and 14.467MHz. Their weather information format is quite different and will give you an idea of European weather conditions and allow you to practice your German. When not sending weather info they run a RTTY message loop below at 50bauds/425Hz shift.

German RTTY station with message loop. Deciphered via MultiPSK.

German RTTY station with message loop. Deciphered via MultiPSK.

In closing, make sure to also check out the NAVTEX broadcasts found just below the AM broadcast band on 490 and 518 KHz; using YaND or MultiPSK you’ll be able to receive these transmissions, but remember you’re not on HF, you are on MW (medium wave), where signal distances are shorter and present a greater reception challenge. YaND software has a NAVTEX broadcast schedule built in as seen below; you have to identify your specific NAVAREA or navigational area, then look at the times and frequencies to determine when to listen in. My QTH is in NAVAREA 4. Lots of interesting information is passed in these NAVTEX transmissions so listen in and have fun!

YaND NAVTEX schedule for various NAVAREAS.

YaND NAVTEX schedule for various NAVAREAS.

NAVTEX on 518 KHz from station VAR-9, New Brunswick, CAN. Messages begin with “ZCZC.”

NAVTEX on 518 KHz from station VAR-9, New Brunswick, CAN. Messages begin with “ZCZC.

Mario Filippi (N2HUN), is the author of this post and a regular contributor to the SWLing Post. Click here to read Mario’s guest posts.

Bill recommends the Signal Identification Wiki

31meterband-waterfall

Many thanks to SWLing Post reader, Bill, who shares a link to this Signal Identification Guide:

http://www.sigidwiki.com/wiki/Signal_Identification_Guide

Curious if any readers have been using this guide–seems like a convenient resource to ID those numerous signals on the bands. Entries show what each signal looks like on a spectrum waterfall display and provides audio clips.

Thanks for the tip, Bill!

A Review of Multipsk Software for Digital Modes and More

http://ak3q.com/wp-content/uploads/2016/01/MPSK2.jpg

Over the last year or so I have been using a really full-featured digital mode software called Multipsk, and it has become my go-to software for most digital modes. Back in September 2015 I wrote an extensive review of the software for The Spectrum Monitor (TSM) which Owner/Editor Ken Reitz has graciously allowed me to post on my blog at All Things Radio. Thomas has written numerous articles for TSM, and will attest to its emphasis on so many aspects of the radio hobby. If you are not a subscriber already you really do not know what you are missing!

The program boasts over 75 modes, not counting some of the many sub-modes or variations, and new modes are being added all the time. There is a free version and a registered version, with the paid mode costing around $45 (U.S.) The free mode will handle a lot of really great modes, but I confess, it was the additional “professional” modes which really made purchasing the registered version a must for me. Whichever way you go, you will not be disappointed. As I have noted on my blog and in the article itself, I consider the registration fee some of the best money I have ever spent for computer software.

As an added bonus, the free or registered version can be run on as many computers as you have in your home, and multiple instances of the program can be run on the same computer provided they are in separate directories. This is a great feature, and it means there is basically nothing going into the Windows registry file–the program runs right from the directory. My only problem is not having enough antennas to have as many instances of the program running as I would like!

I hope you will take time to read my review and then get the program–I think you will be suitably impressed as I was! (I have it running on XP machines through Win10, so compatibility should not be an issue.)

Robert Gulley, AK3Q, is the author of this post and a regular contributor to the SWLing Post. Robert also blogs at All Things Radio.

VOA Radiogram 128 on a cheap Tesco shortwave radio

VOA-Radiogram

SWLing Post reader, Christopher, lives on the north coast of Labrador, Canada. He recently contacted me regarding the purchase of a new receiver–he’s currently stuck with a very inexpensive analog portable he purchased at the UK grocery store, Tesco: the Tesco RAD-108.

While the RAD-108 has poor sensitivity and selectivity, it’s still (evidently) more than capable of receiving the VOA Radiogram. Many thanks to Christopher for sharing this video he found on YouTube:

STF Broadcast #2 Schedule

STFradio
(Source: STF Radio International)

STF Radio International
Broadcast #2

November 30 0500-0600 UTC
5110 / 7490 / 7570 / 7730 / 9330 The Americas
9955 The Carribean
17645 Asia
Preshow Warm-up!!
November 30 0400-0500 UTC
7730 Khz The Americas

PLUS! Rebroadcast for EU
November 30, 2014 1600-1700 UTC
6095 kHz EU
“I can see the radio wave.”

A digital announcement from STF Radio International

STFradioSTF Radio International just shared the following digital announcement. Yes, you’ll need to decode this message from SoundCloud with an application like FLDigi:

STF also mentioned that a text version of this announcement with follow in the next few days (but surely it’s more fun to decode the digital version!).

You should make the time to decode STF Radio International broadcasts if at all possible.  Their QSL cards are some of the best in the business.

VOA Radiogram this weekend, July 5/6

VOARadioGram(Source: VOA Radiogram)

VOA Radiogram this weekend will include news about reductions to the shortwave transmissions of VOA and other stations of US international broadcasting. These cuts were effective on 30 June.

Fortunately, VOA Radiogram remains on shortwave, at least for now.

Here is the lineup for VOA Radiogram, program 66, 5-6 July 2014 (all in MFSK32 except where noted):

1:33 Program preview
2:45 Major reductions to US shortwave broadcasts, with image
8:10 Car fumes affect pollinating insects
10:10 Test of Mars landing craft a success, with image
14:23 India launches satellites at low cost, with MFSK64 image
20:32 Spanish: Triple black hole discovery, with image
25:59 Closing announcements

Please send reception reports to radiogram@voanews.com

VOA Radiogram transmission schedule
(all days and times UTC):
Sat 0930-1000 5745 kHz
Sat 1600-1630 17860 kHz
Sun 0230-0300 5745 kHz
Sun 1930-2000 15670 kHz
All via the Edward R. Murrow transmitting station in North Carolina.

The Mighty KBC will transmit a minute of MFSK64 Saturday at about 1130 UTC on 6095 kHz, and Sunday about 0130 UTC (Saturday 9:30 pm EDT) on 9925 kHz. Both frequencies via Germany. Reports to themightykbc@gmail.com.