Frugal Radio: 2020 SDR Guide Ep 2 – Using Free Online SDRs

Over on his YouTube channel Frugal Radio has released the second episode in his 2020 SDR Guide series. In this video, Frugal Radio shows how to connect to remote SDRs such as KiwiSDR OpenWebRX, WebSDR, SDR-Console v3 Servers, and SDR# SpyServers. He shows how to use these remote SDRs to monitor long range aviation channels, amateur radio operators, and VHF Public Safety channels in the US. He also demonstrates how to decode HFDL signals from aircraft using WebSDR and free software, and verifies the aircraft locations via online tracking sites.

2020 SDR Guide Ep 2 : How to use over 500 remote SDRs free online (webSDR, KiwiSDR & HFDL decode)

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Mighty Mik

At the 9 minute mark you route the audio from U of Twente to Virtual Audio Cable… how? is that using a microphone or is there a checkbox i don’t know about? thanks


I am not the creator of the YouTube video, but I think I can answer your question…

Virtual Audio Cable (VAC) is a third-party Windows application that allows you to (for example) connect the audio output of one application like an SDR receiver to the input of another application like an audio data decoder application. You open VAC and choose which audio ports are connected together.

In the YouTube video I believe what he is actually doing is splitting (in-parallel) the SDR receiver application audio output between the Line-Out port (which after amplification reaches the speakers) and the input of the audio data decoder application. The term “splitting” is a bit misleading here, the audio routing is actually streaming digital data within the PC, so there is no loss of signal level and no added distortion or delay.

One of the oldest Virtual Audio Cable applications from 1998 is authored by Eugene Muzychenko, it is proprietary, Windows only, and costs $30 USD per instance for home use. I believe Muzychenko’s Virtual Audio Cable is what is shown in the YouTube video. Here is a link to Muzychenko’s Virtual Audio Cable:

Read more about Muzychenko’s Virtual Audio Cable application here:

If you search around on the Internet there are some free and even cross-platform VAC-like applications available out there. One VAC application that is free, open-source, and cross-platform is called JACK. But JACK is a bit complex to setup and it is command-line only. However, there are cross platform GUI front-end applications for JACK available, they are usually Qt or Java based. Here is a link to the JACK Project:

Eugene Muzychenko

Strictly speaking, there is only one software product called “Virtual Audio Cable”. 🙂 Since 1998 and for many years, there was no confusion, this name was strongly associated with the appropriate product/application. Then some similar software product vendors started using this widely-know name to promote their software, like many manufacturers of fake fashion items use brand names to increase sales of their production. This created confusion, and now many software users who say “I use Virtual Audio Cable” don’t really know which product they are using.