Audio Difficulty with Pi 2x Board

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This topic contains 9 replies, has 3 voices, and was last updated by  Aaron, N3MBH 1 month, 4 weeks ago.

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  • #2933

    Hello Dan and Aaron
    This is Jeff-WB9OUF from the CTCSS vs COS thread, I have an Audio problem, and I need your help to determine whether it is hardware or software in nature.
    To Recap, my hardware is:
    1) Raspberry Pi 3b+
    2) ICS Pi 2x Controller board
    3) 32 Gb San disk Micro SSD
    Software:
    1) OpenRepeater program version#2.1.1
    I downloaded the image, expanded the files, and configured the program via the UI.
    I build the DB-9 to DB-25 cabling to connect the controller to the repeater using the “Active Low” “CTCSS indicate” to Pin #7 COW from RX on the Pi-2 board, as per our previous discussions.

    This is where the fun starts:

    I Key and release the repeater, I get:
    1) Courtesy tone
    2) Squelch tail of appropriate length
    3) Voice and CW ID’s at proper times at appropriate level
    No voice transmit audio, no signal present at either Q1 or Q2 measuring points, and No force ID and the DTFM command of “*”. Regardless of “R input pot.” Setting…tried multiple points.

    I put my scope on DB-9 Pin #5 and got RX Discriminator output
    On Pin #4 I saw output for ID’s and Courtesy tones….but not output for voice audio!
    Here is everything I’ve tried:
    1) Thinking the 10-pin header to female DB-9 might be defective I traded it with the Port 2 dongle with the same results.
    2) Powered down the system and re-powered up, —no change, same results.
    3) Re downloaded a fresh image to a fresh SSD card, expanded the files, and reconfigured a fresh copy of “OpenRepeater”—–No change, same results.

    Could this be a defective Pi 2x board? I think I’ve eliminated everything from my DB-9 connector to the repeater.

    As one last test, I reconnected the Repeater’s old controller, and it works as well as before.
    I’m lost…..any and all suggestions would be greatly appreciated.

    73

    Jeff-WB9OUF

    #2934

    Dan Loranger
    Forum Moderator

    Hi Jeff,

    Are you measuring the input audio on the resistor at Q1/Q2 or the unconnected pad? If using the unconnected pad then you wont see any audio, its actually a gpio signal. Be sure to measure on the 0 ohm resistor that shorts the traces together. The Q1 and Q2 were meant to be a hardware audio lockout feature that never really worked right so we just removed the feature.

    Dan

    #2935

    Thank you Dan,
    After trying everything I described above. I employed my favorite line from the movie “Contact”
    “All things being equal, the simplest answer is usually the correct one”, In my case it simply involved disabling “Flat audio” After doing that everything worked, and levels where easily adjusted.

    One thing, my audio an echo-like quality to it, is there a way to “tweak” audio quality, and is it easily explained?

    Thank you again,
    73 Jeff-WB9OUF

    #2936

    Dan Loranger
    Forum Moderator

    Jeff, can you please do a quick recording of the audio so I can hear the echo effect. This isn’t normal sound behavior.

    Support at ics-ctrl dot com

    Thanks
    Dan

    #2937

    Have an audio file from my phone, how do I attach it to this message?

    #2938

    Aaron, N3MBH
    Forum Administrator

    Jeff,
    Received your audio file and sent it on to Dan and Joe to check out. What type of radios are you using. Are you or have you tried running the transmitter into a dummy load directly. To me it almost sounds like an RF issue getting back into the audio.

    73,
    Aaron – N3MBH

    OpenRepeater is offered free of charge. Find out how you can support us.

    #2939

    Aaron, N3MBH
    Forum Administrator

    Or a ground loop of sorts.

    73,
    Aaron – N3MBH

    OpenRepeater is offered free of charge. Find out how you can support us.

    #2941

    Hi Aaron,
    I am communicating directly with Dan at ICS support, please loop in with him in that I have the feeling that everything is somehow inter-related. Thank you for all the good suggestions, I hope we all together can resolve this situation.
    The Raspberry Pi/2x combination is and will continue to be an excellent controller platform with incredible expansion possibilities.

    73,

    Jeff-WB9OUF

    #2943

    Hello Aaron and Dan,
    Between the two of you, is there anything I could try, or is it software. I really don’t think it’s stray RF, in that the Repeater is in one package and very well shielded. Coax is double-shielded with short runs to the duplexer. Mostly, it wasn’t present with the internal controller active.
    Are there any software adjustments that can be made that could affect a correction?

    73,

    Jeff-WB9OUF

    #2948

    Aaron, N3MBH
    Forum Administrator

    Have you pulled the TX side off the duplexer and just went straight to a dummy load just to rule RF out? Worth a try. I have had RF get into the Pi and audio lines before and cause havoc.

    73,
    Aaron – N3MBH

    OpenRepeater is offered free of charge. Find out how you can support us.

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