Unknown Data Signal on 6317.3 at 0530 UTC

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mfn002

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I was playing around with my RX350 last night when I came across a very weird signal. Unfortunately, I don't have recording capabilities, so I can't post an audio file. Anyway, the signal would begin with what sounded like Morse code than end with a weird "BRRP" sound, almost like the ringing you hear when you call somebody on the phone. I checked back in at 0600, and it had switched to 6316.0, where I found it again this morning at around 1300 or so. I've never heard this signal before. I also stumbled across numerous high-speed Morse stations:

04906.0 (at 0559)
06488.0 (at 0531)
07047.5 (at 0533)
08696.0 (at 0535)
09083.5 (at 0536)
10100.0 (at 0538)
10151.7 (at 0539)
10428.0 (at 0540)
10993.0 (at 0541)
11036.0 (at 0542)
 

ka3jjz

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The station you describe was likely Shipcom LLC/WLO radio. The BRRP sound was likely a PACTOR 1 ''free signal' - essentially it's an announcement that the frequency (or station) is available for traffic

Here's Shipcom's website - go to the bottom for the PACTOR freqs..

ShipCom LLC Frequencies

If you get into this heavily, you should belong to the UDXF Yahoo group which covers utilities like these, along with those CW stations you mentioned.

Mike
 
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mfn002

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The station you describe was likely Shipcom LLC/WLO radio. The BRRP sound was likely a PACTOR 1 ''free signal' - essentially it's an announcement that the frequency (or station) is available for traffic.

Yeah, that's sort of what I thought. I guess it was on 6317 not 6317.3. As for the CW stuff, I have TERRIBLE luck with CW decoders. Nine times out of ten, it'll come out as gibberish.
 

ka3jjz

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There are many reasons why CW software doesn't work well - some can't handle the various methods of how CW is sent (we call them 'fists') - automatic vs.hand, etc. Propagation always is another cause, as is not properly setting the passband in your receiver, and setting up the CW software correctly. It's hard to diagnose this without more info.

Mike
 

mfn002

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There are many reasons why CW software doesn't work well - some can't handle the various methods of how CW is sent (we call them 'fists') - automatic vs.hand, etc. Propagation always is another cause, as is not properly setting the passband in your receiver, and setting up the CW software correctly. It's hard to diagnose this without more info.

Mike

I'm actually not using software. I'm using an MFJ-462B Multi-Reader.
 

ka3jjz

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GL, no wonder...in this case, MFJ means Mighty Fine Junk, and it applies here.

Those kinds of readers are very limited in what they can do - particularly when it comes to reading CW. There are MANY very good decoding packages that can do a much better job.

One question though - many receivers have the ability to automatically set a CW offset so the tone (usually 800 hz) comes out correctly. Did you do that with your 350, if it can (I suspect not, since the freq that was reported was off by 300hz)? That's pretty important for a lot of readers, both hardware and software based. Generally speaking, they won't decode somewhat reliably without it (I tried 2 or 3, including MixW and MultiPSK...). Mike
 

ka3jjz

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Another good rule of thumb - at least I found this to work when I had a RX320. Make sure you can narrow down to 1 signal. Listening at a bandwidth of 3 khz means you will have several CW signals in your passband, which will give most readers fits, unless you can 'point' to one specific signal. Narrowing down to 500 hz or even narrower, if conditions warrant, is a must.

Next use any available audio filtering - it sometimes helps get the residual noise out of the signal. I was fortunate enough to have an old MFJ audio filter that actually worked pretty well. It will take some experimenting to fine tune how to use that filter, but once you have a range that seems to work well, mark it down so you can replicate that setting on another signal.

And of course, set that 800hz offset. I understand that the RX350's manual is pretty sparse, but there a more detailed one floating around, perhaps in the RX350 Yahoo group .

Mike
 
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DaveNF2G

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Commercial stations generally don't have "fists" any more as the traffic is sent by computer.
 

ka3jjz

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which don't always send at the same speed and spacing from one station to another (just like a human). Not exactly a human 'fist', but a variance nevertheless

And there is one night - I've forgotten the name - where hand keyed CW is used by maritime stations. So while that's generally true, there are exceptions to the rule....Mike
 

mfn002

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I'm not so sure it's CW now. The CW is very fast with no spacing and seems to originate from only one point. There are no pauses for a response. On April 26, for example, in the period from 0530 UTC until 0600, I found the following frequencies:

04906.00
06488.00
07047.50
08696.00
09083.50
10100.10
10151.70
10428.00
10943.00
11036.00
 

Token

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I'm not so sure it's CW now. The CW is very fast with no spacing and seems to originate from only one point. There are no pauses for a response. On April 26, for example, in the period from 0530 UTC until 0600, I found the following frequencies:

04906.00
06488.00
07047.50
08696.00
09083.50
10100.10
10151.70
10428.00
10943.00
11036.00

Are you familiar with the sound of FSK or RTTY? I ask because most of your freqs are on or near FSK / RTTY frequencies.

Example can be found here, look under STANAG 4481 FSK:
Signal Identification - HF Underground


Looking at your freqs:

- Your 4906 kHz, on center freq of 4905 kHz is STANAG 4481 FSK 850 Hz shift (actually not on right now, but normally is)
- Your 7047.5 kHz, nothing seen right now but this is a part of the ham 40 meter band that is often used by RTTY signals
- Your 8696 kHz, on center freq of 8694 kHz is STANAG 4481 FSK 850 Hz shift
- Your 9083.5 kHz, on center freq of 9085 kHz is STANAG 4481 FSK 850 Hz shift
- Your 10151.7 kHz, on center freq of 10153 kHz is STANAG 4481 FSK 850 Hz shift
- Your 10428 kHz, on center freq of 10430 kHz is STANAG 4481 FSK 850 Hz shift
- Your 10943 kHz, on center freq of 10945 kHz is STANAG 4481 FSK 850 Hz shift
- Your 11036 kHz, on center freq of 11039 kHz is 450 Hz shift FSK, RTTY from DDH9, Hamburg Germany

Pretty coincidental that 8 of your 10 freqs are very near either active or known FSK or RTTY frequencies, and it is not even night time here yet. I bet sundown or later I will find RTTY or FSK near the other 2 freqs.

Without a recording of what you are hearing that is the best I can do.

T!
 

ka3jjz

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Supposedly Sorcerer is one package - apart from the expensive Krypto, Hoka, Wavecom, etc. - that can handle STANAG4481 - however, these signals are often encrypted, unless you catch them sending a test tape (there have been some sporadic reports of this) in the clear.

Here's a link...

Sorcerer Decoder Download | KD0CQ

Mike
 

Token

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Supposedly Sorcerer is one package - apart from the expensive Krypto, Hoka, Wavecom, etc. - that can handle STANAG4481 - however, these signals are often encrypted, unless you catch them sending a test tape (there have been some sporadic reports of this) in the clear.

Here's a link...

Sorcerer Decoder Download | KD0CQ

Mike

Yes, STANAG 4481 FSK is almost always encrypted. And that encryption is one way to tell if you have 4481 FSK or some other FSK that is similar, for example the Russians use an 850 Hz encrypted FSK that can be difficult for new listeners to discern from 4481 FSK.

Using Sorcerer, or one of the high end analysis / demodulation packages, the software will often tell you when it receives a KG-84 frame or initialization. If KG-84 encryption is present it cannot be the Russian signal.

The example I linked to includes the KG-84 initialization.

T!
 

mfn002

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Are you familiar with the sound of FSK or RTTY? I ask because most of your freqs are on or near FSK / RTTY frequencies.

Example can be found here, look under STANAG 4481 FSK:
Signal Identification - HF Underground


Looking at your freqs:

- Your 4906 kHz, on center freq of 4905 kHz is STANAG 4481 FSK 850 Hz shift (actually not on right now, but normally is)
- Your 7047.5 kHz, nothing seen right now but this is a part of the ham 40 meter band that is often used by RTTY signals
- Your 8696 kHz, on center freq of 8694 kHz is STANAG 4481 FSK 850 Hz shift
- Your 9083.5 kHz, on center freq of 9085 kHz is STANAG 4481 FSK 850 Hz shift
- Your 10151.7 kHz, on center freq of 10153 kHz is STANAG 4481 FSK 850 Hz shift
- Your 10428 kHz, on center freq of 10430 kHz is STANAG 4481 FSK 850 Hz shift
- Your 10943 kHz, on center freq of 10945 kHz is STANAG 4481 FSK 850 Hz shift
- Your 11036 kHz, on center freq of 11039 kHz is 450 Hz shift FSK, RTTY from DDH9, Hamburg Germany

Pretty coincidental that 8 of your 10 freqs are very near either active or known FSK or RTTY frequencies, and it is not even night time here yet. I bet sundown or later I will find RTTY or FSK near the other 2 freqs.

Without a recording of what you are hearing that is the best I can do.

T!

Here's a recording of the CW traffic:
https://vimeo.com/126369885

...and what I think is PACTOR.
https://vimeo.com/126370090

Just so you'll know, I switched from my RX350 to my VR5000 because the 5000 seems to be less susceptible to interference than the RX350.

Sent from my iPhone using Tapatalk
 

Token

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Here's a recording of the CW traffic:
https://vimeo.com/126369885

...and what I think is PACTOR.
https://vimeo.com/126370090

Just so you'll know, I switched from my RX350 to my VR5000 because the 5000 seems to be less susceptible to interference than the RX350.

Sent from my iPhone using Tapatalk

Your "CW" is not CW, but rather is FSK or RTTY.

Your PACTOR is station WLO, out of Mobile Alabama, with CW ID and ARQ mode channel marker.

By the way, most utility stations like this are tuned in USB, not LSB.

T!
 

ka3jjz

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While there are some data signals that are easy to identify by ear - HFDL vs. ALE comes to mind - many others sound very similar, but are using different protocols. That's why many rely on a spectrgraph or waveform to actually 'see' what the signal looks like. These patterns can be very helpful in identifying a particular mode - and sometimes with that, the user. Of course the better the quality of the signal, the more accurate the waveform.

I mentioned this topic in this thread...

http://forums.radioreference.com/shortwave-data-decoding/307024-many-waveforms-website.html

And there's a link to a website with many spectrgraphs and waveforms for different digital protocols

Many of the better decoding packages have this ability, but if you don't have them, there are alternatives, such as SpectraVue (link below) and several others

http://www.moetronix.com/spectravue.htm

Mike
 

mfn002

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Are these frequencies I mentioned assigned to any individual station? They seem to pop up pretty randomly.
 
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