Tuesday, 11 March 2014

YaDD network Logging

I'm using a Beta Version of YaDD from Dirk Claessens which now includes the ability to send all received messages across the network (LAN or Internet) to a central logging server.

This collates all the messages from multiple copies of YaDD into one text file for processing outside of YaDD itself, and from this has developed a small web-site, running on a Linux PC in my shack:

GM4SLV DSC Online Logging

I've written a Linux Shell Script which reads the collated log from multiple receivers (up to 8 have been connected at any time) and creates filtered views of the logs.

It's still very much work in progress, and I can't see an easy way of moving it to an off-site webserver and to retain the functionality, so it stays in-house for now.

Thursday, 21 November 2013

Yet Another DSC Decoder (YaDD)

For the last couple of months I've been helping to beta test a new MF/HF DSC Decoder which is being written by the author of the excellent YaND (Yet another Navtex Decoder), Dirk Claessens.

The project has developed very quickly, after I asked Dirk on the 5th of September if he'd ever considered a DSC companion to YaND.

By the 17th of September I was trying out YaDD for myself, with Beta version B01.

This was the bare bones, the first of a long sequence of beta versions, and it gave only the raw symbol from the DSC signal, using the same demodulator code lifted from YaND, and it simply printed the received symbols on the screen.

Later versions would improve the demodulator performance, with changes to parameters that better suited the short duration DSC transmissions. Although the modulation of DSC and NAVTEX is the same, 170Hz shift / 100bd FSK, NAVTEX transmits much longer messages. A DSC decoder needs to find and lock onto a DSC signal much more quickly than a NAVTEX signal, and with NAVTEX there's time in a transmission to perhaps re-sync and only miss a few characters. DSC needs to get it all, in one go, to correctly decode a message with no errors - there's little room for human interpretation of a garbled message with DSC.

The improvements came thick and fast.

YaDD B02 changed the format of the displayed signal, and increased the range of DSC symbols that were decoded.

YaDD improved on each release. One thing we studied was the relative decode performance of YaDD compared to DSCDecoder and MultiPSK - the standard DSC Decoders used by the majority of DSC DXers. Each change in YaDD meant another comparison to see if we could spot any improvement in the numbers of successful messages decoded by YaDD.

Many of the improvements were adding more and more DSC formats to YaDD's repertoire - Selective Calls, Area Calls, All Ships Calls, etc. The ITU document (R-REC-M.439) was studied, and studied again (and again... and again), finding new in increasingly intricate combinations of symbols for encoding frequencies, positions, channel numbers, TEST Calls, and Distress Alerts and many more.

I made Perseus off-air recordings, and selected various 15 minute chunks which could be used to quickly measure the number of messages decoded by the three decoders. Along side this were long off-air sessions with multiple decoders, and lots of number crunching of the received messages, and trying to spot any systematic flaws in YaDD's performance.

At version B06, released on the 10th of October,  YaDD could now display the Coast Station name, by reference to a new MMSI-to-CoastStation lookup list that I compiled, using the ITU website, the Admiralty List of Radio Signals, the GMDSS Master Plan and the wonderful RWW Database of DSC signals reported via the DGNavlist, NDBList and NAVTEXDX yahoo groups.

Quickly came version B07 on the 24th of October, which added DSC Area Calls, and increased the amount of displayed  information (positions, frequencies etc,)  taken from decoded messages.

Three more Beta testers joined us, and we continued to test, and count, and test, and count. Problems in how YaDD coped with the convoluted mess of symbols that make up DSC messages were quickly spotted and Dirk speedily found a fix, time after time. The ITU's "Recommendation ITU-R M.493-13" is the bible, and has been our constant companion throughout all the testing and re-testing, but it's far from an easy read, and each new hiccup meant deciphering another obscure section.

Read it for yourselves, sometime...


With version B09,  published on the 1st of November, pretty much everything was in place - many DSC message types were now handled correctly and the weak-signal decode performance was on a par with DSCDecoder and MultiPSK.

After more comparative testing - which was getting more difficult now, since all three of the decoders showed that they coped differently on different signals - DSCDecoder might get a message which was missed by both MultiPSK and YaDD, but then YaDD would get one missed by the other two. Only after long overnight runs, with hundreds, even thousands, of messages could an overall assessment be made.

B0.91 came out, the final one before a public release.

This had some changes to modem parameters, and at first things seemed to be better, but comparing DSCDecoder with YaDD B09 and B0.91 side-by-side showed that perhaps it was a backwards step

Test 1)


YaDD b0.91  vs MultiPSK vs DSCDecoder

MultiPSK : 163
DSCDecoder : 163
YaDD b0.91 : 153

Test 2)

Overnight test 1622UTC Friday - 0741UTC Saturday

YaDD b0.90  vs  YaDD b0.91  vs DSCDecoder

DSCDecoder : 721
YaDD b0.90 : 752
YaDD b0.91 : 697

YaDD B09 seemed better, and for the release of YaDD V1.0 Dirk rolled back the detrimental changes, while keeping others that did improve things, and YaDD V1.0 was ready.

YaDD V1.0 was announced to the world on the 14th of November, 2013:

Hello all,

YaDD 1.0 is available for download; see instructions below as they were sent to the beta team : John Pumford Green, Dave Onley, Martin Augustus and Stephen "TheAppleMac". I wish to express my sincere thanks to the testers for all the work done. Without your help,  YaDD would not have been where it is today: V1.0 available in just over 2 months!

Special thanks go to John Pumford Green for providing invaluable information, test data and for the many interesting discussions.  

Regards - Dirk

YaDD v1.0 had a new colour scheme, and a real database of received signals, rather than a simple text file.

I tested it, one last time, and sent Dirk the good news

I've now had YaDD V1.0 running for almost 36 hours on 2MHz.

The scores so far:

YaDD v1.0 : 1920
DSCDecoder : 1923

Now that we are happy that YaDD is on a par with other decoders, Dirk is concentrating on improving the user features - watch out for Database filters, and many more things in the near future.

Here is a sneak preview of V1.1, with the ability to filter based on a correct or faulty Checksum, and on whether the sender was a Ship or a Coast Station.... 

More enhancements will surely come along quickly.

YaDD has gone from my question, on September the 5th :

Hello Dirk,

This is a very general enquiry... and please ignore it if you have no

YaND is the absolute pinnacle of NAVTEX software - extremely sensitive,
with features tailored to the DXer, especially the ability to create
Reports for posting to the NAVTEX list for inclusion in REU/RNA/RWW.

Have you ever considered a similar software for MF/HF DSC?

At present there are 2 options for DSC DXing: DSCDecoder and MultiPSK.

DSCDecoder isn't (from the accounts of others) as sensitive as MultiPSK.
MultiPSK is too large and not specific for DSC DXing.

Neither are really designed for DXers in the same way YaND is.

I also think that YaND is also probably much more sensitive than DSCDecoder.

I'd really like a "YaND for DSC" or "Yet another Dsc Decoder" and I'm
sure many more people would. I love being able to simply click the
database entries I want to send to REU and then magically there's a
properly formed report... DSCDecoder and MultiPSK require a lot of
manual intervention!

If you are not interested, then that's perfectly understandable, but I
thought I would just enquire.

Best wishes,


to a fantastic DXers DSC decoder, in only 2 months.

Thanks Dirk!

YaDD Timeline:

First enquiry : 5 September 2013

Beta Releases:
B01 17 September 2013
B02 21 September 2013
B03 26 September 2013
B05  6 October 2013
B06 11 October 2013
B07 24 October 2013
B08 26 October 2013
B09  1 November 2013
B091 5 November 2013

Official Releases:
V1.0-prerelease  12 November 2013
V1.0 Public Release  14 November 2013
V1.1-prerelease  19 November 2013

You can download YaDD from the NBDList website:

Sunday, 8 September 2013

Almost Real Time DSC Logs

I've been tinkering with some Linux Shell scripting and using a script to split my current DSC Decoder log file into separate chunks, and then to make them accessible from the web.

Every 10 minutes the script will copy the current day's logs, and then make available the logs containing:

1) Unfiltered "Decoded" and "Formal" logs from 2MHz and 8MHz

2) Filtered Logs from both bands:

  • GMDSS Training - Dover (Snargate Radio) : MMSI 002320204 - 2MHz and 8MHz
  • Messages sent FROM a coast station - 2MHz and 8MHz
  • Messages sent FROM a ship station - 2MHz and 8MHz
  • Messages that are NOT TEST Calls - 2MHz and 8MHz
  • Messages TO or FROM "Shetland Coastguard" - 2MHz
  • Messages TO or FROM "All UK Coastguard" - 2MHz
  • Messages TO or FROM "All USA Coast Stations" - 2MHz and 8MHz
  • Messages of type "DISTRESS" - 2MHz and 8MHz

The files are updated every 10 minutes, and a new set of files is started at midnight UTC each day - so the only data available is for the Current Day.

To access the data :


The Shell Script which splits and formats the files (with my first ever use of the Linux "sed" command) is below

DATE=`date -u +%y%m%d`


# Put new lines on the log files
sed 's/$/\n/g' $infile1 > /home/gm4slv/gm4slv_2mhz_dsc.txt
sed 's/$/\n/g' $infile2 > /home/gm4slv/gm4slv_2mhz_formaldsc.txt
sed 's/$/\n/g' $infile3 > /home/gm4slv/gm4slv_8mhz_dsc.txt
sed 's/$/\n/g' $infile4 > /home/gm4slv/gm4slv_8mhz_formaldsc.txt

# Look for Dover (Snargate)
cat /home/gm4slv/gm4slv_2mhz_formaldsc.txt | grep 002320204 > /home/gm4slv/dover_formal_2mhz.txt
cat /home/gm4slv/gm4slv_8mhz_formaldsc.txt | grep 002320204 > /home/gm4slv/dover_formal_8mhz.txt
cat /home/gm4slv/gm4slv_2mhz_dsc.txt | grep Snargate > /home/gm4slv/dover_2mhz.txt
cat /home/gm4slv/gm4slv_8mhz_dsc.txt | grep Snargate > /home/gm4slv/dover_8mhz.txt

#look for distress
cat /home/gm4slv/gm4slv_8mhz_formaldsc.txt | grep distress > /home/gm4slv/distress_formal_8mhz.txt
cat /home/gm4slv/gm4slv_2mhz_formaldsc.txt | grep distress > /home/gm4slv/distress_formal_2mhz.txt
cat /home/gm4slv/gm4slv_2mhz_dsc.txt | grep distress > /home/gm4slv/distress_2mhz.txt
cat /home/gm4slv/gm4slv_8mhz_dsc.txt | grep distress > /home/gm4slv/distress_8mhz.txt

# Look for "not Test"
cat /home/gm4slv/gm4slv_2mhz_formaldsc.txt | grep -v test > /home/gm4slv/nottest_formal_2mhz.txt
cat /home/gm4slv/gm4slv_8mhz_formaldsc.txt | grep -v test > /home/gm4slv/nottest_formal_8mhz.txt
cat /home/gm4slv/gm4slv_2mhz_dsc.txt | grep -v test > /home/gm4slv/nottest_2mhz.txt
cat /home/gm4slv/gm4slv_8mhz_dsc.txt | grep -v test > /home/gm4slv/nottest_8mhz.txt

# Look for Shetland
cat /home/gm4slv/gm4slv_2mhz_dsc.txt | grep Shetland > /home/gm4slv/shetland_2mhz.txt
cat /home/gm4slv/gm4slv_2mhz_formaldsc.txt | grep 002320001 > /home/gm4slv/shetland_formal_2mhz.txt

# Look for UK
cat /home/gm4slv/gm4slv_2mhz_dsc.txt | grep CG]-G > /home/gm4slv/ukcg_2mhz.txt
cat /home/gm4slv/gm4slv_2mhz_formaldsc.txt | grep 0023200 > /home/gm4slv/ukcg_formal_2mhz.txt

# Look for USA
cat /home/gm4slv/gm4slv_2mhz_dsc.txt | grep ]-USA > /home/gm4slv/usacg_2mhz.txt
cat /home/gm4slv/gm4slv_8mhz_dsc.txt | grep ]-USA > /home/gm4slv/usacg_8mhz.txt
cat /home/gm4slv/gm4slv_2mhz_formaldsc.txt | grep 00366 > /home/gm4slv/usacg_formal_2mhz.txt
cat /home/gm4slv/gm4slv_8mhz_formaldsc.txt | grep 00366 > /home/gm4slv/usacg_formal_8mhz.txt

# Look for Coast Stations
cat /home/gm4slv/gm4slv_2mhz_dsc.txt | grep 'from;\[' > /home/gm4slv/coast_2mhz.txt
cat /home/gm4slv/gm4slv_8mhz_dsc.txt | grep 'from;\[' > /home/gm4slv/coast_8mhz.txt
cat /home/gm4slv/gm4slv_2mhz_formaldsc.txt | grep 'from;00' > /home/gm4slv/coast_formal_2mhz.txt
cat /home/gm4slv/gm4slv_8mhz_formaldsc.txt | grep 'from;00' > /home/gm4slv/coast_formal_8mhz.txt

# Look for Ship Stations
cat /home/gm4slv/gm4slv_2mhz_dsc.txt | grep -v 'from;\[' > /home/gm4slv/ship_2mhz.txt
cat /home/gm4slv/gm4slv_8mhz_dsc.txt | grep -v 'from;\[' > /home/gm4slv/ship_8mhz.txt
cat /home/gm4slv/gm4slv_2mhz_formaldsc.txt | grep -v 'from;00' > /home/gm4slv/ship_formal_2mhz.txt
cat /home/gm4slv/gm4slv_8mhz_formaldsc.txt | grep -v 'from;00' > /home/gm4slv/ship_formal_8mhz.txt

# Remove blank lines on grep -v'd files
sed -i '/^$/d' /home/gm4slv/nottest_2mhz.txt
sed -i '/^$/d' /home/gm4slv/nottest_8mhz.txt
sed -i '/^$/d' /home/gm4slv/nottest_formal_2mhz.txt
sed -i '/^$/d' /home/gm4slv/nottest_formal_8mhz.txt
sed -i '/^$/d' /home/gm4slv/ship_2mhz.txt
sed -i '/^$/d' /home/gm4slv/ship_8mhz.txt
sed -i '/^$/d' /home/gm4slv/ship_formal_2mhz.txt
sed -i '/^$/d' /home/gm4slv/ship_formal_8mhz.txt

# Put new-lines on the filtered files
sed -i 's/$/\n/g' /home/gm4slv/dover_2mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/dover_8mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/dover_formal_2mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/dover_formal_8mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/shetland_2mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/shetland_formal_2mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/distress_formal_2mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/distress_2mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/nottest_2mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/nottest_8mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/nottest_formal_2mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/nottest_formal_8mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/distress_formal_8mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/distress_8mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/ukcg_formal_2mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/ukcg_2mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/usacg_2mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/usacg_8mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/usacg_formal_2mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/usacg_formal_8mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/coast_2mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/coast_8mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/coast_formal_2mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/coast_formal_8mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/ship_2mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/ship_8mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/ship_formal_2mhz.txt
sed -i 's/$/\n/g' /home/gm4slv/ship_formal_8mhz.txt

# Remove the ; on the Decoded files
sed 's/;/ /g' /home/gm4slv/gm4slv_2mhz_dsc.txt > /home/gm4slv/Dropbox/Public/gm4slv_2mhz_dsc.txt
sed 's/;/ /g' /home/gm4slv/gm4slv_8mhz_dsc.txt > /home/gm4slv/Dropbox/Public/gm4slv_8mhz_dsc.txt
sed 's/;/ /g' /home/gm4slv/shetland_2mhz.txt > /home/gm4slv/Dropbox/Public/shetland_2mhz.txt
sed 's/;/ /g' /home/gm4slv/distress_2mhz.txt > /home/gm4slv/Dropbox/Public/distress_2mhz.txt
sed 's/;/ /g' /home/gm4slv/distress_8mhz.txt > /home/gm4slv/Dropbox/Public/distress_8mhz.txt
sed 's/;/ /g' /home/gm4slv/nottest_2mhz.txt > /home/gm4slv/Dropbox/Public/nottest_2mhz.txt
sed 's/;/ /g' /home/gm4slv/nottest_8mhz.txt > /home/gm4slv/Dropbox/Public/nottest_8mhz.txt
sed 's/;/ /g' /home/gm4slv/ukcg_2mhz.txt > /home/gm4slv/Dropbox/Public/ukcg_2mhz.txt
sed 's/;/ /g' /home/gm4slv/usacg_2mhz.txt > /home/gm4slv/Dropbox/Public/usacg_2mhz.txt
sed 's/;/ /g' /home/gm4slv/usacg_8mhz.txt > /home/gm4slv/Dropbox/Public/usacg_8mhz.txt
sed 's/;/ /g' /home/gm4slv/dover_2mhz.txt > /home/gm4slv/Dropbox/Public/dover_2mhz.txt
sed 's/;/ /g' /home/gm4slv/dover_8mhz.txt > /home/gm4slv/Dropbox/Public/dover_8mhz.txt
sed 's/;/ /g' /home/gm4slv/coast_2mhz.txt > /home/gm4slv/Dropbox/Public/coast_2mhz.txt
sed 's/;/ /g' /home/gm4slv/coast_8mhz.txt > /home/gm4slv/Dropbox/Public/coast_8mhz.txt
sed 's/;/ /g' /home/gm4slv/ship_2mhz.txt > /home/gm4slv/Dropbox/Public/ship_2mhz.txt
sed 's/;/ /g' /home/gm4slv/ship_8mhz.txt > /home/gm4slv/Dropbox/Public/ship_8mhz.txt

# Add Tabs on the Formal Files
sed 's/;/\t/g' /home/gm4slv/gm4slv_2mhz_formaldsc.txt >/home/gm4slv/Dropbox/Public/gm4slv_2mhz_formaldsc.txt
sed 's/;/\t/g' /home/gm4slv/gm4slv_8mhz_formaldsc.txt >/home/gm4slv/Dropbox/Public/gm4slv_8mhz_formaldsc.txt
sed 's/;/\t/g' /home/gm4slv/nottest_formal_2mhz.txt > /home/gm4slv/Dropbox/Public/nottest_formal_2mhz.txt
sed 's/;/\t/g' /home/gm4slv/nottest_formal_8mhz.txt > /home/gm4slv/Dropbox/Public/nottest_formal_8mhz.txt
sed 's/;/\t/g' /home/gm4slv/distress_formal_2mhz.txt > /home/gm4slv/Dropbox/Public/distress_formal_2mhz.txt
sed 's/;/\t/g' /home/gm4slv/distress_formal_8mhz.txt > /home/gm4slv/Dropbox/Public/distress_formal_8mhz.txt
sed 's/;/\t/g' /home/gm4slv/dover_formal_2mhz.txt > /home/gm4slv/Dropbox/Public/dover_formal_2mhz.txt
sed 's/;/\t/g' /home/gm4slv/shetland_formal_2mhz.txt > /home/gm4slv/Dropbox/Public/shetland_formal_2mhz.txt
sed 's/;/\t/g' /home/gm4slv/dover_formal_8mhz.txt > /home/gm4slv/Dropbox/Public/dover_formal_8mhz.txt
sed 's/;/\t/g' /home/gm4slv/ukcg_formal_2mhz.txt > /home/gm4slv/Dropbox/Public/ukcg_formal_2mhz.txt
sed 's/;/\t/g' /home/gm4slv/usacg_formal_2mhz.txt > /home/gm4slv/Dropbox/Public/usacg_formal_2mhz.txt
sed 's/;/\t/g' /home/gm4slv/usacg_formal_8mhz.txt > /home/gm4slv/Dropbox/Public/usacg_formal_8mhz.txt
sed 's/;/\t/g' /home/gm4slv/coast_formal_2mhz.txt > /home/gm4slv/Dropbox/Public/coast_formal_2mhz.txt
sed 's/;/\t/g' /home/gm4slv/coast_formal_8mhz.txt > /home/gm4slv/Dropbox/Public/coast_formal_8mhz.txt
sed 's/;/\t/g' /home/gm4slv/ship_formal_2mhz.txt > /home/gm4slv/Dropbox/Public/ship_formal_2mhz.txt
sed 's/;/\t/g' /home/gm4slv/ship_formal_8mhz.txt > /home/gm4slv/Dropbox/Public/ship_formal_8mhz.txt

Wednesday, 4 September 2013

MMSI 002320204 - Dover

After a few days monitoring 8414.5kHz DSC I've seen quite a few ship stations calling the new Coast Station based in Dover. So far nothing has been seen on 8MHz in response to the test calls. Here is a list of what I've seen:

8414.5kHz DSC Calls to/from Snargate Radio, Dover, MMSI 002320204

as received at:

Greenmeadow, Clousta, Shetland ZE2 9LX

60° 17.31´N 1° 25.50´W


Icom IC-R75
Wellbrook ALA1530S+ Active Loop antenna
Software : DSCDecoder by COAA "Centro de Observação Astronómica no Algarve"

002320204 (safety) from 269013000  test REQ 13-08-30 12:39:21

002320204 (safety) from 240969000  test REQ 13-08-31 06:36:20
002320204 (safety) from 636091766  test REQ 13-08-31 07:08:09
002320204 (safety) from 240730000  test REQ 13-08-31 08:22:19
002320204 (safety) from 565396000  test REQ 13-08-31 08:23:18
002320204 (safety) from 636091006  test REQ 13-08-31 12:07:51
002320204 (safety) from 240969000  J3 posn N50° 10' W000° 52' REQ 13-08-31 13:03:17
002320204 (safety) from 636011449  test REQ 13-08-31 19:31:27
002320204 (safety) from 636011449  test REQ 13-08-31 19:32:37

002320204 (safety) from 255803860  test REQ 13-09-01 08:38:55
002320204 (safety) from 247697000  test REQ 13-09-01 09:08:21
002320204 (safety) from 566389000  test REQ 13-09-01 10:29:34
002320204 (safety) from 256182000  test REQ 13-09-01 10:47:17
002320204 (safety) from 636091006  test REQ 13-09-01 11:23:28
002320204 (safety) from 413172000  test REQ 13-09-01 12:30:42
002320204 (safety) from 352732000  test REQ 13-09-01 14:37:28
002320204 (safety) from 538003782  test REQ 13-09-01 15:35:33

002320204 (safety) from 240957000  test REQ 13-09-02 07:11:28
002320204 (safety) from 240957000  test REQ 13-09-02 07:22:57
002320204 (safety) from 240957000  test REQ 13-09-02 08:39:46
002320204 (safety) from 636014078  test REQ 13-09-02 09:21:08
002320204 (safety) from 372404000  test REQ 13-09-02 10:21:22
002320204 (safety) from 256182000  test REQ 13-09-02 11:13:49
002320204 (safety) from 636090971  test REQ 13-09-02 11:28:01
002320204 (safety) from 308542000  test REQ 13-09-02 12:00:24
002320204 (safety) from 235011660  test REQ 13-09-02 12:08:29
002320204 (safety) from 538003146  test REQ 13-09-02 12:24:46
002320204 (safety) from 256182000  test REQ 13-09-02 14:16:15
002320204 (safety) from 538002583  test REQ 13-09-02 15:41:11

002320204 (safety) from 565343000  test REQ 13-09-03 01:51:42
002320204 (safety) from 372979000  test REQ 13-09-03 11:14:07
002320204 (safety) from 256182000  test REQ 13-09-03 11:32:02
002320204 (safety) from 351498000  test REQ 13-09-03 14:49:48

The station is located in Dover, right below a cliff, which must screen it to the north. Here's a Streetview link to see the building, and its antennas:


Saturday, 31 August 2013

8MHz DSC Stations

I started monitoring the 8MHz DSC frequency (8414.5kHz) yesterday and already have received a few interesting coast stations. The distances achieved are of course much greater than on 2MHz

YYYY-MM-DD HH:MM kHz     MMSI      Station / Country
2013-08-30 22:03 8414.50 006221111 Alexandria / Egypt
2013-08-30 20:24 8414.50 005671000 Bangkok RCC / Thailand
2013-08-30 09:30 8414.50 003669991 COMMSTA Boston / USA
2013-08-30 20:07 8414.50 003669998 COMMSTA New Orleans / USA
2013-08-30 09:27 8414.50 003669995 COMMSTA Portsmouth  / USA
2013-08-30 21:01 8414.50 002241022 Coruna Radio / Spain
2013-08-30 23:59 8414.50 002711000 Istanbul / Turkey
2013-08-30 20:14 8414.50 006452700 Mauritius / Mauritius
2013-08-30 23:39 8414.50 002371000 Olympia Radio / Greece
2013-08-30 20:17 8414.50 005030001 RCC Australia / Australia
2013-08-30 21:11 8414.50 004122100 Shanghai Radio / China
2013-08-31 03:35 8414.50 006010001 Capetown Radio / S. Africa
2013-08-31 05:34 8414.50 007100001 Rio / Brazil

I'm quite pleased with results so far, after 24 hours. 

No sign yet of the new station in Dover (MMSI 002320204) - although I did spot three ships calling that MMSI for a test:

The "San Pietro" MMSI 269013000:

002320204;(safety);from;269013000; test REQ;13-08-30 12:39:21;

The "United Emblem" MMSI 240969000:

002320204;(safety);from;240969000; test REQ;13-08-31 06:36:20;

The first two vessels were in the Channel at the time of the Test Calls, according to Marine Traffic

The "APL Shanghai" MMSI 636091766:

002320204;(safety);from;636091766; test REQ;13-08-31 07:08:09;

The third one is listed as its last position being in port in Antwerp, with no AIS signals being received since the 19th of August.

Friday, 30 August 2013

New DSC kid on the block?

A new shore station has been licensed in the UK - "GMDSS Training LLP" based in Dover.

It appears they will be on-air with MF/HF/VHF DSC for training purposes at some time in the future.

Here are the extracts from the UK Notice to Mariners:

The MMSI to watch for is 002320204 

So far no-one in the DSC monitoring hobby has reported logging this MMSI, but several vessels have been logged attempting to call the new station.

I am watching the 8MHz DSC channel for a few days to see what transpires.

The training company website is :


Perhaps they will be logged when they next have a training course running. For MF/HF it would appear that the next GOC/LRC course is due to run week commencing September 16th 2013


Catching a new UK shore station, especially one that will only be active at random times, and on random bands, is going to be quite a challenge.

Thursday, 29 August 2013

US Coastguard cease MF DSC and R/T

I noticed in this month's Radio User mag that the US Coastguard are ending their 2MHz MF watchkeeping. The requirement for a continuous 2182kHz R/T watch has been gone for many years, but most administrations have at least kept the capability. What I find odd is that the USCG have withdrawn the 2MHz DSC service too.




Quoting from the last document...

"a detailed review of several Coast Guard MF sites revealed significant antenna ground deterioration and infrastructure support degradation, leaving the Coast Guard at risk for not being able to receive or respond to maritime distress calls on 2182 kHz or 2187.5 kHz, and not being able to transmit effectively on 2670 kHz. Early last year, as a result of physical site surveys, the Coast Guard confirmed the significant site deterioration and, therefore, the unreliability of receiving MF distress transmissions at many locations."

So the fear of having such poor equipment that they may not be able to receive or respond means that they take the step to rip it all out, and therefore guarantee that they won't be able to.

It looks like I've logged my last 2187.5kHz DSC transmissions from:

 003669991  COMMSTA Boston USA
 003669997  COMMSTA Miami USA
 003669998  COMMSTA New Orleans USA 
 003669995  COMMSTA Portsmouth USA 
 003669931 USCG New Haven USA
 003669999 USCG Stns Group Call USA

Farewell USA on 2MHz. 

At least we might still have St. John's, Placentia, Sydney Harbour from the East coast of Canada to listen to on 2MHz SSB this winter - or are they thinking the same thing as the USA? Thinking about it, I don't recall ever receiving any 2MHz DSC from a Canadian Coast Station.