I'm using SDR# and with virtual audio cable sound is piped to Wavecom W-CODE. W-code recognizes a frequency on 4 and 24 MHz as Pactor-II with 100% confidence, but he can't decode in terminal text window nothing "0". This is something that I can't understand, because I don't have HAM experience.

They say for Pactor that is very adaptive signal used mainly in extreme situation like sea (almost never failed). I'm living far away from the sea, and using default antenna which came with rtl-sdr dongle, with software gain "0" can catch signal -30 dB on 24 MHz (don't matter if is day or night). To visualize more, with gain "0" and with frequency scanner in 0-30 MHz band can catch just 5 signal during the day. That's mean that source is very close or Pactor is very good adaptive signal...

Second question would be regarding w-code. How come that he can recognize signal with "100% confidence", but can't demodulate the wav file? I also tried with sorcerer and MixW, with no luck. Is W-CODE right about Pactor or not?

Screenshot that wcode recognize signal as Pactor-II

I put other files beacuse quota limit under comments!!!

  • $\begingroup$ This is too many different questions. They may be related to each other for you, but their answers aren't. Please post your questions separately, and make sure to include more details (e.g. give a link to the web site of your "pro software demodulator" to clarify what software you are referring to). $\endgroup$ – Kevin Reid AG6YO Oct 8 '16 at 23:30
  • $\begingroup$ Thanks. I put more details about software that was mention in question, and put more information regarding hardware and modification. $\endgroup$ – Credo Tehnologije Oct 9 '16 at 13:09
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    $\begingroup$ Thanks for narrowing it down. Please see my revision — I removed information not part of the question and created separate paragraphs for readability. Also, if you could add a screenshot of the waterfall display for this alleged PACTOR signal and maybe upload the .wav file then it would help people figure out the answer to your question. (As it is, any answer will have to come from speculation or someone knowing W-CODE in particular.) $\endgroup$ – Kevin Reid AG6YO Oct 9 '16 at 13:47
  • $\begingroup$ I'm not versed in terms of PACTOR at all, but: Wikipedia says PACTOR (I) is free and open, whereas you need the patented tech from SDS to mod and demod PACTOR II…IV; that doesn't necessarily stop non-commercial software from decoding it, but are you sure W-CODE is capable of decoding PACTOR II (in addition to detecting it)? $\endgroup$ – Marcus Müller Oct 9 '16 at 14:04
  • $\begingroup$ Also, what is the antenna that came with the RTL-SDR? Mine came with a terrible UHF antenna, and everything that you see on 24MHz with that most likely didn't really originate there, but is some spur mirrored there from internal electronics or via intermodulation from another frequency, or is incredibly strong. $\endgroup$ – Marcus Müller Oct 9 '16 at 14:09

Your PACTOR II signal couldn't be decoded because PACTOR II uses proprietary encoding. There is no open-source decoder; in order for PACTOR II to be decoded, an expensive modem from Special Communications Systems GmbH (SCS) must be used.


It has been my experience that Pactor works best when it is in a conversation with another Pactor system, meaning it is a CONNECTED mode. It really doesn't like it when just monitoring. I believe this is especially true of the newer Pactor modes. Part of this comes from the signal margins that are present on a full circuit and the fact that Pactor can ask for a repeat of a packet if it misses a packet of data or it comes through corrupted. Keep in mind that Pactor would have to re-sync to the signal if it started losing chunks of data because of errors on the radio circuit. Without this re-syncing there could be no lock.

Hope this helps a little


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