ND2E's Blog

The Signalink USB came in the mail yesterday so I took it and a couple of other soundcard interfaces to the Kingsport club meeting where I was giving a presentation on Digital Modes in ham radio. The presentation went well until I got to the keying schematic where I had an error in the grounds. I will work on that later today so the presentation is corrected.

Today I installed the Signalink … no problems were experienced, I followed their directions for jumpering. Nothing unusual there. Neat thing is each radio cable comes with a jumper diagram so you don’t have to look it up on the web. The box also had the hex key that is neeed to disassemble the box so you can install the jumpers. That is a nice touch.

I put it on the air after a couple of adjustment in HRD/DM780 v5 Beta and to the computer. You need to assign the new interface in HRD and make sure that Microsoft hasn’t assigned the new soundcard as the default soundcard.

PTT setting is straight forward. adjust the HRD soundcard TX level until the Signalink keys then, adjust the Tx level adjustment on the Signalink for proper ALC action, (Don’t forget to make sure the SWR is low so as not to affect the ALC.)

After two QSOs into Arizona with good quality comments I shut down for lunch and updates to the blog and web site.

So at this point I think the Signalink USB is a quality unit and can see why many of my friends have bought it.

Cio/73 de ND2E, Joe

Well, it isn’t a bad soundcard-just needed to reinstall the software. So now I have to make a decision…do I reinstall the audio lashup to get back on the air or do I wait for the Signalink USB to arrive before I set things up again?

The other day I was in a QSO when the other operator mentioned seeing what he called hum bars on my transmission. It seemed stranged at the time but I did back off on the Tx audio a bit and he said it was better.

A couple of days later I was trying to work to the North East and the FT-857 would not key. (I was running digital VOX.) Knowing that I had not changed the Tx Audio levels since the previous session, I started testing. The radio would key when I changed the PTT logic to the CAT but it was extremely insensitive when set to digital VOX. That seemed a bit strange so I pulled the Tx audio connector and plugged in my headset. What to my wondering ears did appear but a harsh low pitched growl when I started to transmit.

I switched DM780 to the internal soundcard to verify that it was a soundcard problem not a computer problem. It was the external soundcard so I am now off the air waiting for my new Signalink USB to arrive.Hopefully it will be here Thursday of Friday so I can get back on the air this weekend.

Late last summer when I was having computer and radio problems, a station in South Carolina mentioned that I was driving the Tx audio a bit hard because he could see distortion on the waterfall. There was a noticeable but faint set of tracks … not nearly as bad as some of the Cuban stations but still noticeable. At that time I dialed back on the audio going to the TS-2000 and he said it cleared up – Mostly. At that time I did not recognize a sound card problem…I monitored the audio with my headset but did not notice any distortion. I my mind the external soundcard I have used for several years was degraded and continuing to fail but I did not notice it.

So now I wonder how is the best way to actually monitor the output signal of the soundcard – really, how to monitor the IMD of the radio/souncard combo. I am open to suggestions, not all Digital Mode software supports IMD measurement and in most instances it really is only a measure of the Rx audio path from the receiver to the waterfall and is subject to significant overdrive in the audio and DSP chain.

If anyone has a good recommendation – I am willing to try it.

73 de ND2E/Joe