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FLDIGI and WebSDR

Discussion in 'OS: Mac OS' started by KB7PWJ, Feb 25, 2018.

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  1. KB7PWJ

    KB7PWJ Ham Member QRZ Page

    I'm interested in PSK31 and trying to get a taste of it and a feel for FLDIGI by decoding audio from a WebSDR, but so far I've netted nothing but gibberish, when I'm lucky. Running OS 10.12.6 here.

    I've tried both feeding the WebSDR audio to FLDIGI through the speakers, and feeding it in with a virtual cable. (My preferred method, but right now I'll take anything.) So far I've tried to decode both CW and PSK.

    PSK gets me random characters, when I get anything at all, which isn't often. Never anything readable.

    In CW I can sometimes get a row of random characters - again, when I get anything at all. So far my record is 5 consecutive readable words.

    I've watched some YouTube tutorials about how to do this, but they're sparse, and generally feature an OM saying "do this, do that, and look, it works!" I've done this and I've done that, but I'm still getting the above results. (For the record, my process boils down to: setting the desired mode in Configuration, configuring input source to built-in microphone or my virtual cable, then setting the mode in the upper left of the FLDIGI window to USB for PSK31 and CW for CW. Then I find a signal on the WebSDR and adjust the red signal selector as necessary on the FLDIGI waterfall.)

    I must be making a mistake so obvious that the YouTube guys don't bother to mention it. Any clues to what it might be?

    TNX,

    Rob
    KB7PWJ
     
  2. K3DCW

    K3DCW QRZ Lifetime Member #212 Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    Here are some things to consider:

    Make sure you're in USB mode ON THE WEBSDR for PSK31 and for CW. Fldigi expects a SSB signal in most cases.

    Using the speakers and microphone is a very poor way to decode PSK31: too much ambient noise. A virtual audio cable like LOOPBACK is ideal.

    Make sure the squelch control is turned off in Fldigi (lower right corner).

    Depending upon the codec used at the WebSDR side, you may be getting compression of the audio signal which could cause problems. There could also be some sampling rate issues, although I don't think that is the most likely issue.

    Are you sure you're listening to PSK31? Best place is usually 14070.0 USB, but you'll often see PSK63 and 125 in there as well.

    I presume you've selected PSK31 or CW from the pulldown menu in Fldigi?

    Decoding CW with Fldigi can be hit or miss unless it is VERY clean. Doing so with audio coupling (speaker/mic) is likely nearly impossible.


    Again, just some ideas of things to look at. Some are quite basic and not meant as an insult: rather, they're simply there to cover all the bases.
     
  3. KB7PWJ

    KB7PWJ Ham Member QRZ Page

    Thanks, K3DCW! That gives me a place to start.

    I'm using the iShowU Audio Capture VAC. FLDIGI seems to hear... something... sometimes, when I use it. (Though I can't hear anything, even though I've set FLDIGI to play out.)

    I do set the WebSDR to USB. But you're spot on that I'm not even entirely sure what PSK31 sounds like; my instruction so far comes from YouTube tutorials, but digital modes can sound very similar to someone with no prior experience.

    I'll try your hints. No worries about insults. At this point, I'm too dumb to know if I'm being insulted. I greatly appreciate your response.

    TNX,

    Rob
    KB7PWJ
     
  4. WV8A

    WV8A Ham Member QRZ Page

    fldigi author W1HKJ's site contains a "Sights & Sounds of Digital Modes" page.
    http://www.w1hkj.com/modes/index.htm
    which presents BPSK varieties, and, across the top are tabs to select thirteen other digi modes.

    Chuck
    WV8A
     
  5. KB7PWJ

    KB7PWJ Ham Member QRZ Page

    Thanks, Chuck! That'll help.

    Rob
    KB7PWJ
     

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