March 18, 2011 — You may recall the disgust I expressed in this space only a few days ago over my eBay purchase of a Signalink USB interface. I sniped the bid on the interface’s auction months ago, and only recently decided to put the unit on the air.
After repeated trys at getting the unit to work (including going inside and reflowing every solder joint I could find), I gave up; I actually tossed it in the garbage can, only to retrieve it. At the very least, I could put it on eBay as a non-functioning unit; some soul with better troubleshooting skills might wish to have a project.
How would you describe it? Well, it works great on transmit; and it actually will work on receive — if you sample the audio from the built-in mic on my little netbook (actually I’ve found the Signalink works surprisingly well this way, just taking the audio via the mic on the laptop). So yeah, it sorta works, but it won’t work when the audio is supposed to come from the packet/digital DIN plug on the radio, through the cable and into the Signalink. For some unknown reason, there’s no signal path for received audio through the connector.
Then I remembered that last year I ran my first Signalink on my Yaesu FT-7800 dualbander on 2-meter packet. On that setup, the cable doesn’t use the rear digital port, it uses the mic jack and the speaker out of the radio … hmmm …..
I decided to hook the second (defective) Signalink up for packet on the Yaesu dualbander; the audio in would avoid the RJ connector on the interface, instead entering via the 3.5 mm audio input line from the radio speaker output.
After trying to figure out MixW’s setup for packet — and after confirmation that a packet signal still even exists within range — I found that the interface worked fine in this application! I may have to go back and look at the PC board again, there’s got to be a short to ground or an open circuit on the audio input via the Signalink’s RJ connector.
Of course, as it turns out I won an auction earlier this week for — yep — a third Signalink USB inteface. The seller guarantees it, and I’m going to try the thing out as soon as it arrives. I didn’t intend to have 3 of these interfaces, but that’s what I have now. My intention was to hook up the Signalink to my FT-817 and run digital modes QRP; I can’t do that with my second one due to its “problems,” so perhaps I can with the one that’ll arrive soon.
JUMPERS, JUMPERS, JUMPERS. I love the ease of using the Signalink USB interface (when it works, hi!). One of the quirks is that when you switch it from one rig to another, you have to change the jumper block inside the rig. It’s not difficult to do, but it makes it a little inconvenient to switch the interface around. At least now I can leave one on HF, one on VHF and the third will be QRP portable. That’s the plan, anyway!
When you buy a Signalink, you have to also purchase the appropriate cable, and then decide if you want to manually set the jumpers for your choice of rig (top photo), wire your own jumper block (middle photo), or purchase a ready-to-play jumper block that is appropriate for your application (bottom photo).
The plug-and-play jumper blocks are relatively new; for my money, its the only way to go. I don’t understand why the company didn’t consider doing this themselves years ago; I can tell you from experience that wiring your own jumper block takes a good eye and steady hand. As the images at right illustrate, when you make your own jumper block, you have to put these tiny copper jumper wires into the slots , then solder them without shorting them to an 
adjacent pin. And you have to keep the solder to a minimum to allow the “cap” to go back on the jumper block. If I were going to use the interface and dedicate it to a single rig, I think the yellow jumper wires — which are provided — is probably easier than trying to wire the jumper block.
When you see someone selling a Signalink that’s a few weeks old, I’ll bet you they bought it and then didn’t want to mess around with wiring the jumper block. As I said, the plug-and-play jumper block is the only way to fly.
The good thing about the jumpers is that you only need four of them in most cases — ground, PTT, mic and speaker. The plug-and-play jumper blocks sure make life easier. Users of eHam.net have given the Signalink some stellar reviews and an impressive 4.9 rating; I can confirm the marvels the unit offers, though as you can read here, sometimes technological glitches can rain on your digital parade.
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