Chinese CODAN intruding into the 40m band

[VK3RX]

Posted on the Radio Reference forum by KA3JJZ:

From Ary Boender in the UDXF- the list of logs is too long to post here, but here's the test. Any transcription errors are mine...

Since mid 2016 I logged CODAN selcalls on 7, 8, 11 and 13 MHz. Until a week ago I didn't know who they are. Australian State Emergency Services was suggested but there are too many stations and they are also transmitting 24/7. That doesn't fit the SES activities. Besides that SES and affiliated service do not use these frequencies. So, if it isn't the SES, what is it???

It appears to be a HF Vehicle Tracking System. The syatem is used by companies in various countries, but the specific traffic that I heard all come from one place: the Spratley Islands in the South China Sea. China is building artificial islands in the Fiery Cross Reef. The Chinese started their activities in 2015. The first transmissions from that area were noticed in early 2016. The tracking system uses CODAN equipment that sends selcalls to base stations. The base stations use the received data to track the ships, barges and cars used for the building activities. Sometimes GPS data is mentioned in the CODAN messages, but so far I have no idea how to read it.

Voice traffic has been heard in Mandarin following CODAN calls. These are actual calls, not the tracking devices. They are answered by the reverted tones sent by the receiver's CODAN radio to acknowledge the receipt of the signal.

Base stations IDs include: 1111, 2222, 3333, 4444, 5555, 6666, 7777, 8888, 1188, 6363, 6969, 7474, 7979, 9898, etc. Note the combinations: either XXXX or XXYY or XYXY. Easy to recognize. These IDs are in the "TO" field.

Frequencies in USB. The center frequency is 1785Hz higher.

7103, 7106, 7109, 7112, 7121, 7124, 7127, 7130, 7133, 7139, 7142, 7145, 7148, 7157, 7160, 7918, 7921, 7933, 7936, 7938, 8003, 8006, 8009, 8012, 8015, 8021, 8024, 8027, 8030, 8033, 8041, 8066, 8072, 8075, 8078, 8596, 9047, 9090, 11149, 11159, 11163, 11168, 13431, 13452 kHz and maybe more.

The Chinese are intruding the 7MHz HAM bands with this service.

Examples of GPS data:
ESN 117117
ESN 117255

[VK2WP]

Surprised the Chinese military are using Codan equipment for their fleet tracking, would have thought they would have plenty of their own systems.

Last night happened to arise just before 1.00am and spent some time tuning around 40M and yep, there they are. Tabulated are the frequencies I heard Codan telemetry tones on.

1358UTC USB in KHz

7106, 7108, 7112, 7121, 7124, 7130,7139, 7142, 7144, 7157, 7160, 7194.

As well heard a swarm of AM S/W broadcasters mostly Chinese

7210, 7220, 7225, 7230, 7235, 7240, 7245, 7245, 7255, 7264, 7270, 7275, 7285, 7290.

Seems everybody wants to use 40M including Indonesian pirates whom turn 40 into a chanting cesspool. And don't forget the radar from time to time.

[VK3RX]

The Codan data is being heard as far away as Europe, according to posts on the UDXF.

[VK6ZFG]

Just because they are using signalling format that CODAN uses does not mean they are actually using CODAN equipment. Other manufacturers also use the same signalling format.

[VK2WP]

True, Barret and others use the same format, although a while back on QRZ there was a Chinese ham making many posts about how much he liked Codan radios for his ham radio.

English not the best, think he even had some photos of Codans stacked up on each other if I remember correctly.

This surprised me as would have thought the Chinese would make their own H.F gear.

Afraid Spratley Islands are not really accessible, not the sort of place you could take your sailing boat and have a look.

Still its a pity I cannot speak Mandarin, would be a gas to call up the radio operator and ask him for a qsl card.

Wonder what their postal address would be ?

[VK6ZGO]

I think CODAN, the signalling system, came first, & Codan (the company) thought it was a nifty name & registered it.
A bit like HMV with "The Gramophone Company", or "Fernseh" as a name for a range of TV equipment.

[VK4ADC]

Just off on the same tangent, I first encountered the term 'CODAN' back around the 70's or 80's, when it was the acronym for 'Carrier Operated Device Anti Noise' as it applied to the use of a noise squelch arrangement on HF SSB radios.  

Whether it was related to CODAN, the company, in the early stages would probably only be known by a historian.

[VK4WDM]

Maybe they think that 7MHz is a "han" radio band not a "ham" radio band.      (You might have to think about that for a while).  

Wayne VK4WDM

[VK3RX]

An old school buddy in Adelaide worked for EILCO (Electronics Instrument and Lighting Company). In the 1970's they went into a joint venture with AES (Associated Electronics Services) to develop and produce HF radios, and they then adopted the company name Codan Limited.

My recollection re the 'Carrier Operated Device Anti Noise' system for HF receivers termed "CODAN" (at least within DCA) is I think that system was developed by AWA.

The signalling system between radios was developed by Codan Limited.

[VK4ADC]

Got to admit at this point that I am an old DCA boy. Started with them as a trainee radio tech in '68 so maybe the emphasis should be on the word OLD.

[VK3RX]

I started as a Flight Service Officer in August 1978

[VK2CSW]

I am not sure this helps anyone:

From:
http://www.lucabarbi.it/product/hoka-ele...codan.html

CODAN CHIRP decoder: measures the real center frequency of the transmitting station and tunes the data decoder automatically, and decode the ALE part of the transmission.

CODAN DATA decoder: is a QPSK scheme it uses 16 in-band tones from 656.25 Hz to 2343.75 Hz, spaced 112.5 Hz apart. These centre frequencies are derived from a 600 Hz to 2400 Hz frequency spread and 112.5 Hz per Quaternary Phase Shift Keyed (QPSK) channel.

Also:
http://www.wavecom.ch/content/ext/Monito...ndatam.htm

and

https://www.sigidwiki.com/wiki/Codan_Data_Modem

[VK2WP]

Thanks for those links, interesting how they do things.

[VK3RX]

FYI the WIA is aware of this interference on the 40m band, and is keen for reports via their Intruder Watch service.

[VK2WP]

A report has been put in to the WIA. It appears others have heard these tones as well.

[VK2CSW]

While I agree that the Intruder Watch reports are important, I do wonder what anyone can do about this, if they are coming from the Spratly Islands.

I just cannot see the Chinese "Peoples Liberation Army Navy" giving two hoots about anything that any other country or international agency has to say about it.

[VK3RX]

I did hear that complaints re the Chinese radar reported on 40m some months back was probably the cause of them abruptly moving down to below the band.

Perhaps they concluded a simple change of frequency was worth stopping the complaints and attention.

[VK2CSW]

We can only hope that they play nicely, although in other matters in that area they don't play so nice.

[VK3RX]

The WIA Intruder Watch report of April 2019 includes reports of these signals.

Note the text below the report:

the frequency band 7100–7200 kHz is also allocated to the fixed and the mobile, except aeronautical mobile ®, services on a primary basis. (WRC-15)

"141B" is the ITU Table of Allocations Footnote 141B.

So it appears these parties may be legitimate.

Intruder Watch Report April 2019