I’ve really been enjoying PSK31 over the last couple weeks, even more so since I added a Signalink USB interface to the mix. My home-brew FT-857D Soundcard Cable was working, but I had two issues with it. First, was impossible to set the audio in such a way that the radio’s VOX triggered consistently while keeping the ALC level at zero. The best I could do was keep the ALC to a minimum. Second, I’m pretty sure I was getting some RFI in the computer.
While I had the parts available to trigger the radio’s transmitter via software, I didn’t have the necessary parts to deal with the RFI issue. Since the Signalink interface is so widely recommended, I went ahead and purchased one. So far, I’m very happy with it.
A note to fellow Mac users, I had to increase the receive audio level in the USB Signalink by closing jumper 2 on the board. Prior to doing that, the receive audio was too low, even with the RX level turned all the way up. The jumper instructions are in the Signalink manual, you might want to check your audio levels and/or go ahead and close the jumper when you have the case open if you are using a Mac.
When I wanted to try out PSK31, I hacked together a cable for my 857D out of spare parts. The 6 Pin Mini DIN connector came from a discarded keyboard and the audio jacks came from a spare auxiliary patch cable.
Before you build one for yourself, note that it is widely recommended that the radio and computer are isolated as not to cause a ground loop. This cable does not provide any isolation. So proceed at your own risk. There are plenty of people that use cables like this without issue–I’m not one of them. I had some issues with the cable, they weren’t the end of the world, but I’ve since upgraded to using a Signalink USB.
The pinout for the data jack is provided in the FT-857D Operator’s Manual (PDF). It is also shown here. One need only connect the data out (1200 bps) from the radio to the computer’s sound input and the data in from the radio to the computer’s sound output. Both of these connections also need to be connected to the ground. Remember, that the diagram here is of the data jack on the back of the radio, make sure the pins you solder to in the connector will mate with the right holes in the jack.
As I said, this cable has worked well for me, but it does have a few drawbacks compared to other methods of connecting a radio and computer. However, this is a very quick* and inexpensive way to try digital modes. If you like it, you may wish to enhance your audio connection.
* This method is quick if you have the parts. If you don’t you’ll need to find them somewhere. If you can’t get your hands on an old PS/2 keyboard or mouse, you can order a 6 pin Mini DIN connector (e.g. Digikey Part #CP-2060-ND).
I missed the 20th anniversary of this site by a couple days (it was on the 7th). Ten years ago, I marked the occasion by listing the most popular posts.
Homebrew Yaesu FT-857D Soundcard Cable
Bose 901 Equalizer Repair
A Dashing Dashboard with Raspberry Pi
PSK31 with an FT-857D and a Mac
More PSK31
NYC to Montreal and Back (in Four Parts)
Motorcycle Parking at NYC Muni-Meters
Pomodoro Timer
Temperature Logging with Twine and ThingSpeak
DIY Air Variable Capacitor
The only post that appears on both lists is about the motorcycle trip to Montreal. I’m always surprised with the number of people interested in making a soundcard cable or repair a Bose 901 EQ. By the way, PDF schematic diagram for that EQ is not represented on this list, but is probably viewed more than any of these other pages.