The wet string chronicles…

A few days ago I finally got around to getting my SignaLink USB interface hooked up to my Yaesu FT-897 for the primary purpose of using that setup for PSK31 operating (and other similar ’soundcard’ based digimodes). I will continue to use my Kenwood TS-480 for RTTY where a Rigblaster Plug & Play interface is wired up for FSK operating.

FT-897 with SignaLink USB

I have previously used the SignaLink SL-1+ for PSK31 and other digimodes with great success. Both devices really are very easy to setup and I was particularly impressed with just how straightforward it was to get going with the USB version. I connected the interface box to the radio with the supplied USB cable, connected to the radio via a mini 6 pin data connector, turned on the radio and tuned to 14.070, fired up Digipan (which I have been using for approaching 4 years now) and was rewarded with a waterfall display full of nice clear signal traces.

The built in sound card certainly seems to be less prone to noise than the original which relied on the PC internal soundcard. This is certainly something I’ll investigate further by comparing noise levels between the SignaLink and the Rigblaster (which uses the PC soundcard).

Having got receive working to my satisfaction I set about trying to reply to some of the CQ callers in the waterfall display - this was where I found one of the two minor niggles I encountered. The PTT wasn’t being triggered by the audio output from the PC. It turns out this was just a matter of insufficient audio output from the built in USB soundcard - a quick tweak in the Windows audio settings for that device to set to max audio out seemed to resolve the issue. Fine tune for RF drive is then by the TX level on the SignaLink.

waterfall with PSK31 signals

Having resolved this little niggle the device switches to transmit reliably whenever the software enters ‘Send’ mode. Initial reports from stations contacted confirm that all is working well.

One other minor niggle (the second of two) was an issue I’d seen reported elsewhere, that of the sample rate for the soundcard resulting in slightly offset RX/TX frequencies. This manifests itself in the waterfall display with the received signal being slightly offset from the last received frequency after transmitting. The default sample rate was 11,025Hz but by changing this to 10,000Hz the problem goes away. I have seen others have said they set the sample rate to 8,000Hz but 10,000 worked fine for me.

I’m really pleased with this combination for PSK31 work and I’ll look forward to using this mode a lot more over the coming months. Having used PSK31 for most of my operating a few years ago and having worked lots of ‘new ones’ in that period, I have more recently concentrated on RTTY and CW so it’ll be good to see if I can get any more new ones now I’m QRV PSK31 again.

Dean Amateur Radio, Pictures FT-897, PSK31, RTTY, SignaLink, TS-480, Yaesu