Choppy Receive Audio Through SoftEther VPN through Starlink

Kevin Va3KGS · March 2023

Because I am unable to use SmartLink through a Double Nat, I have to use SoftEther VPN as my work around. Remote station; Laptop Windows 10; Cogeco ISP; SmartSDR V3.4.21.

Local Station; Desktop Windows 10; StarLink ISP; SmartSDRV3.4.21.

Radio Setting; Display Min/Max.. were made with no change; Filters adjusted - no change ; All DAX settings are shut off.

Second Remote Station was connected at the same time to assisted in trouble shooting and heard same choppy signal, there was no change in the Audio after second remote station disconnected.

Attached are network info that I was able to capture.

Note that it was reported that little to no latency was report on the transmitting audio.

Any suggested work arounds on the received choppy audio is appreciated.

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Va3KGS Starlink.jpeg

Thanks Kevin

Ha Gei · March 2023

i have seen choppy RX on 2 occasions :

#1 Short overloads on a lenovo 320 laptop, can be corelated to high cpu load.

#2 Laptops with shared video memory, while the 320 even has a onboard video with shared memory..it works 98% of the time , but the CoreI7 lenovo T560 with Nvidia videocard is UNUSABLE , crackles all the time ..

If you can stream music from a pc across the softether bridge, then the link is not the problem.

Did you try the laptop on-site ?

Harry

Mike-VA3MW · March 2023

@Kevin Va3KGS

Can you describe the packet routes? Since you are dealing with double NATing, is all your data traveling through an intermediate server? This is what is likely happening since you are likely not able to establish a peer to peer connection between the end user and the radio.

It looks like this:

[Radio] <> [VPN broker]<>[End user]

When you use SmartLink, it looks like this

[Radio]<>[End user]

What are your FPS and RATE settings on SmartSDR? If you slide them all the way to the left, it will reduce your upstream bandwidth and might help?

As well, when you are doing a non-SmartLink connection to a radio, the audio stream is not compressed since the radio believes it is on a local LAN with unlimited bandwidth.

The choppy audio is 100% related to UDP (the audio stream) packet loss as it is being sent from the radio to the end user.

In order to diagnose this further, you need to consider every piece of hardware that touches the data packets.

73

Kevin Va3KGS · March 2023

Hi Mike

Thanks for answering.

We have done all of the trimming to achieve a 100% audio signal, through the Smartlink gui.

I see two places where possible hardware improvement could happen. (others may suggest other spots of improvements).

eliminate the WIFI between Starlink and Dlink Router. I do have Starlinks Network adapter (not used). I can start with that.
possibly may need to change out the Dlink to something bigger and better that can do ethernet as well as WIFI.
If I need to change out the Dlink (~10years old), what would be a suggest unit to purchase?

Thanks

Kevin, Va3KGS

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Kevin Va3KGS · March 2023

Hi Harry

Thanks for your response. I did try to connect locally before I came back home and it wasn't letting me do that. Not sure why? So I had my other Flexy friend sign into my radio from his home QTH. He is using a desktop computer. He also got the same choppy audio signal as I was.

Not saying it is not an issue with my laptop, but its not even going to be considered in a changeout program!!

As you see in my comment back to Mike (MW), I will try switching out the Starlink WIFI and us their network connector into the Dlink, and then get my Flexy Friend to sign back in for a test.

Stay posted OM.

Cheers

Kevin, Va3KGS

Choppy Receive Audio Through SoftEther VPN through Starlink

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