Why are internet connections to the same SDR different?

Wa3enkWa3enk
in General Chat

This may be a bit hard to explain so please bear with me.

Myself, my brother, and a friend all use a certain SDR when conditions are bad on 80 meters. My friend and I are closer to each other than my brother. We all get a slot on the SDR. I can hear my friend fine. My friend can hear me fine. My brother's signal doesn't make it to the SDR.

At times my brother, who is farther away, can hear me. At times he can hear my friend. At times he can hear both of us. Other times he can't hear either of us. Of course when I say fine I mean with a reasonable signal to noise ratio and can't hear means a poor signal to noise ration. Sometimes when I hear my friend fine, my brother cannot copy him at all. At the same time on the same SDR. We have experienced this on more than one SDR.

I find this very odd. How can a signal, which has already been received and digitized, be sent on the internet and arrive at two different locations with a different signal to noise ratio?

Does anyone have any thoughts?

Rod

Comments

  • WA2ZKDWA2ZKD

    Yes it is hard to explain! I suggest you use nomenclature like TX1, TX2, RX1, RX2 etc in place of brother and friend etc.

  • G8JNJG8JNJ

    Hi Rod,

    I'm not sure I understand what you are describing.

    However I have a suggestion for a test you could try.

    Choose a KiWi and get yourself and your other net users to use up all of the receiver slots. Make sure one of you tunes to the frequency you actually want to listen to, but mute the audio

    Then using a new browser tab, get you and the others try to connect to the same KiWi again, and you should be presented with the queuing screen, something like this.

    image.png

    If you all then select the blue hyperlink showing the receiver that is tuned to the frequency you are interested in, you will all be sharing exactly the same receiver and audio.

    You should see something like this where I have selected RX3.

    image.png

    John,

    Rather than having to perform this workaround, maybe there could be (or already) is) an option to be able to do this from the users tab in the control panel (or elsewhere), rather than just retuning the users existing receiver to the same frequency as another user.

    It would be handy for amateur radio club nets, where the available receiver slots fill up very quickly but they are all tuned to the same frequency, using the same mode?

    Or maybe you can already do this with a suitable url string that could be shared between net users?

    Regards,

    Martin

  • Wa3enkWa3enk

    Martin,

    Thank you very much for your reply. I know it is hard to understand. Basically it looks like signals over the internet degrade with distance. I don't think so.

    I think that when you try to log on to an SDR that you are already logged on to, it rejects you.

    You have made me think. Suppose I am the first to log into the SDR. Rather than my group try to log in - they should camp on me. Is there a way to camp if the slots are not all filled?

    Thanks again.


    Rod

  • jksjks
    edited June 2023

    There is already a URL parameter to take you directly to the camping page:

    my_kiwi:8073/?camp or my_kiwi:8073/?...(other URL stuff)...&camp

    It should be unaffected by "prevent multiple connections from the same IP address" being true, allowing you to test it with multiple camps from the same browser.

    So the first member of your group has to make a regular user connection. Then all the subsequent members can make camping connections and camp the audio of the first user's connection.

  • jksjks

    The only thing I can think of to explain this is that someone in your group is using different settings that would effect the noise floor. Like a different agc threshold setting or having one of the noise filters active.

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