KX3 - FLDIGI/BPSK125- MacBookPro - unable to receive

Discussion in 'OS: Mac OS' started by KM4QVM, Aug 30, 2017.

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  1. KM4QVM

    KM4QVM Ham Member QRZ Page

    Good morning fellow Mac-Hams.

    I am brand new to Digital Modes - setting it up to support local ARES communications.

    I have USB connection between KX3 and Mac as well as Audio Cables.
    KX3 is set to USB - DATA - DATA A

    I am able to transmit without problems : received excellent report from a Ham one county away.

    Nothing on receive! (I was able to copy some PSK31 for a time - no longer)

    I am pursuing 2 avenues: 1. Audio signal level ( Phones output from KX3 to Mic Input on MacBookPro) : I have tried a 10dB, 600 Ohm Pie Attenuator - nothing. Next step is to adjust down to 6dB and try again. 2. Looking at calibrating the sound card using WWV - last night the WWVs were too weak to successfully complete this exercise.

    Appreciate any guidance.

    Thanks and 73s,

    David / KM4QVM Macon, Ga
     
  2. KM4QVM

    KM4QVM Ham Member QRZ Page

    Reading around this site: I am going to explore : 1. removing the audio cables between the KX3 and the Mac and 2. going to look to use the USB AUDIO CODECs instead by:

    Using the Audio Midi Setup Utility (found under Applications/Other,
    not under the usual System Preferences):
    •click 'Window/Show Audio Devices'
    •You should see four selections in the left-side panel...◦Built-in Microphone
    ◦Built-in Output
    ◦USB Audio CODEC
    ◦USB Audio CODEC
     
  3. K7GQ

    K7GQ Subscriber QRZ Page

    Would you enumerate these problems please?
     
  4. KM4QVM

    KM4QVM Ham Member QRZ Page

    ( love the sailboat! ) I do not have any problem TRANSMITTING.... my problem is receiving - I do not see any signals on the Waterfall - or in the Signal Window....
     
  5. KM4QVM

    KM4QVM Ham Member QRZ Page

    UPDATE: 8/31/17: I am running Sierra OS - found the Midi Setup - under Applications - Utilities - Midi Setup .. however NO USB Codec to be found!!!! even with KX3 connected via USB and controlling the Radio via the Mac! With NO attenuation between the KX3 and the Mac, I was able to copy PSK31 successfully once more. Weird - Is this a "level thing"? Is PBSK125 THAT particular? I did learn that the Mic Input is STEREO - 2 channels. The attenuator pad that I made was a single channel device - I "commoned" the channels as they went into the Mac.
     
  6. K3DCW

    K3DCW XML Subscriber QRZ Page


    Yes, your KX3 is connected to the rig via USB, but that's for rig control, not audio. If you're using the Mic input on the Mac, then you wouldn't be looking for USB Audio CODEC -- that is only used for USB audio devices. You'd need to select the built-in input, but I'm not certain what that is called on your particular MacBookPro model. However, once you select it, you'll also want to go to your Sound Preferences and make sure it is selected for input and that the activity levels are showing activity -- if not, adjust the input level either from the rig or via the Sound Preferences (not all input types are adjustable). Then, you'll need to make sure that whatever sound device you're actually using is selected in Fldigi for input under the soundcard settings.
     
  7. KM4QVM

    KM4QVM Ham Member QRZ Page

    Dave, thanks, so much for the detailed response: I concur. Makes perfect sense - to use the USB for control and the audio cables for the signals. I am able to transmit BPSK125 perfectly. My problem is with RECEIVE .. I DO see activity on the INPUT Bar Graph on my MacBookPro. I AM able to copy PSK31 traffic but NOT BPSK125 which is the whole reason that I am setting up FLDigi - to support local ARES efforts - and we use BPSK125! Is it a level problem, a passband/bandwidth problem, or something else? Something else that is a difference between PSK31 and BPSK125.... scratching my head!!!!
     
    Last edited: Sep 1, 2017
  8. K3DCW

    K3DCW XML Subscriber QRZ Page

    So, when you said earlier " I do not see any signals on the Waterfall ," what you meant was that you don't see any BPSK125 signals, but you ARE seeing PSK31 signals on the waterfall?

    Is it possible that you're only seeing PSK31 signals that are being picked up via the MBP's Microphone, and the SNR simply isn't sufficient for the BPSK125? THis is a common problem for people using laptops with built-in microphones near the screen when the correct input device is not selected in Fldigi.

    What year MBP is this?
     
  9. KM4QVM

    KM4QVM Ham Member QRZ Page

    Yes... true statements: I cannot see BPSK125 signals in the Waterfall... I do see PSK31 signals in the waterfall and am able to copy them. ( I apologize for the misleading description posted earlier)

    My MBP is 2011.

    I am able to choose between Built-In Microphone and Built-In Input .... I have Built-In Input selected.

    Thanks for the hint regarding SNR .. I may narrow my Passband and see if that makes a difference..
     
  10. K3DCW

    K3DCW XML Subscriber QRZ Page

    Assuming you're using the Audio Input jack on that 2011 MBP, then it should be a stereo line-level input. When you go to macOS's Sound Preferences and select the Input tab, you should see "Built-In Input." Does it allow you to adjust the input level, and if so, is it set high enough to allow "action" on the Input level meter right below that?

    Of course, Built-In Input should be selected as your Input sound source in Fldigi as well, under the soundcard settings.

    Which output are you using on the KX3 to feed the audio to the MBP? What do you have your output level set for in the KX3 settings? Perhaps you should bump it up a notch or two.

    Also, in Fldigi, check to make sure you don't have your squelch set too high. Ideally, turn it off (lower right corner of the Fldigi screen) until you get this figured out.

    I'm shooting in the dark here now as the KX3/K3 is fairly simple to hook up to a Mac and there's no reason why it shouldn't work for BPSK125 but work just fine for PSK31, except for not having enough audio signal feeding into the MBP, which would mean that the BPSK125 SNR may simply be too low to get good decode.
     

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