Receiveing AM Stereo using IQ mode

sv1btlsv1btl
edited November 2017 in Signals Received
Receiveing AM Stereo using IQ mode of Kiwi and SODIRA (http://www.dsp4swls.de/sodira/sodiraeng.html)

Tune to a Kiwi, near to an AM Stereo station (http://meduci.com/stations.html). Select the frequency in IQ mode
Set VAC as your default sound card.
Open SoDiRa and set it up as follows:
- Configuration -> Input = VAC, Native Receiever - Using (checked) as Soundcard I/Q data  || Output = pc sound card
- Switch to Demod/Decoding -> "Broadcast" and then select AM Stereo

Some examples:
- http://gnss.0am.jp:8073/?f=1242.00iqz7   .... JOLF - 1242 KHz, AM STEREO - Tokyo, Japan (Nippon Hoso)
- http://38.86.67.206:8073/?f=1220.00iqz5  .... WSLM - 1220 AM STEREO - Salem, IN

Please confirm other AM stereo stations.
WA2ZKD

Comments

  • jksjks
    Are you sure about this? I was reading https://en.wikipedia.org/wiki/AM_stereo and it seems IQ mode would only work if the station were using the ISB (Kahn-Hazeltine) method of stereo transmission.

    The Wikipedia article says most stations use C-QUAM (https://en.wikipedia.org/wiki/C-QUAM) which appears to require more processing (QAM) and also synchronous detection. Sync detection has been on the wish list for some time (WebSDR has it).

    The stations on your list, and others I tried, all had the typical IQ mode "ping-pong" sound between the left and right channels of regular AM signals. I think this occurs when there is a frequency mismatch between the station and the Kiwi and the amplitude of the I and Q channels is slowly fading up and down. This is identical to how the IQ carrier rotates in a circle on the IQ display extension for an off-frequency AM signal.

  • sv1btlsv1btl
    o.k. you are probably right. You can delete the post.
  • jksjks
    edited November 2017
    Oh, wait a minute, I misunderstood. You're talking about sending Kiwi IQ data to SODIRA which does have an AM stereo demodulator (although the documentation doesn't say which type). So you're not just listening to the IQ data as stereo audio directly, which is what I was talking about.

    SODIRA also has built-in DRM which is interesting. I wonder if they started with the Dream code and integrated it?

    I'll have to start up my terribly slow pc and try this out..

  • sv1btlsv1btl
    edited November 2017
    Well, I've received C-Quam stereo AM with SODIRA and Kiwi iq, but after your answer I thought that it was maybe a "pseudo"  effect, although I am sure that I could hear a stereo signal and led in SoDiRa was locked to "Stereo". Unfortunately I didn't find strong AM stereo stations with Kiwis around the world. OLF - 1242 KHz, AM STEREO - Tokyo, Japan (Nippon Hoso) has the best signal, but they don't like nusic very much!... :) 
    I have to test my self, using my Kiwi and a low-power AM stereo C-quam trasmitter that I own (100mW), and make a video for this, but I have to find some free time for these tests.

    Yes, SoDiRa has an excellent DRM decoder, like Dream. The AM demodulator of SoDiRa is C-quam.

    Vmware will be possible a good solution to run Windows on MAC, to test behaviors of Kiwi and windows programs. 
  • sv1btlsv1btl
    edited November 2017
    Screenshot. I have to find a way to make a video capture of my screen... Now they trasmit music (at last) and stereo is definitely well heard!!!

    Attachments:
    https://forum.kiwisdr.com/uploads/Uploader/96/4de59235d2d0db64a398bd4268982a.jpg
  • jksjks
    Okay, great. I will definitely have to try this. Thanks for telling us about it!

  • sv1btlsv1btl
    edited November 2017
    OK, here is the video I've promised. I don't know how long will be stay on YouTube, because of copyright rules, but I hope long enough to see and hear it.
    The station is the same above, but I'll post in the future another, with my equipments.

  • jksjks
    That's excellent!

  • sv1btlsv1btl
    edited November 2017

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