And it’s small enough to build into your own box to make a DIY SignaLink.

It has decoded every digital mode I have so far tried it with. It comes in a small extruded aluminium case, has connections for SP/DIF input and supports sample rates of up to 48kHz so it would probably be suitable for basic SDR use. It costs around £8.50 including postage from China. It doesn’t have a brand name but can be readily identified from the picture and is advertised on eBay as something like “USB 6 Channel 5.1 External Sound Audio Card For Laptop”. I also spent a bit more on a slightly fancier sound card “dongle” which I currently use for computer audio, but which still displayed the inadequacies on weak signals and fast data modes that I have mentioned.įinally I tried the device pictured above. The second I bought thinking it would be good enough for computer audio, which it was, but had to throw it away when it failed after a week. One I threw away after seeing the noise it introduced on the waterfall. I bought two of the cheap thumb sized “dongles”. I have tried a number of these cheap devices. And when I tried to use one of these devices to decode a fast digital mode such as packet, I decoded nothing at all, not a single packet, even though I could see the signal loud and clear on the waterfall. What I do know is that when I played back a recording of very weak CW using one of these devices all I could hear was noise. I have no idea if they are right about the chip. I have had several online discussions bordering on arguments with self proclaimed experts who claim that the sound chip in these cheapo “dongles” is exactly the same as the one in a £100 SignaLink USB interface so the £1 dongle must be just as good. However a great many people claim that the cheapest USB sound card “dongle” costing just 99p on eBay is good enough. The usual solution is to buy a purpose made interface such as a RigExpert or SignaLink (expensive but highly recommended by all who own one) or an external USB sound card.

The popularity of web videos and podcasts means that most ham radio enthusiasts who want to use sound card digital modes no longer want to dedicate their computer’s built-in sound card for that purpose.

The best external sound card for laptop