Building the KD1JV Digital Dial

The KD1JV Digital Dial is a digital display that was designed by Steve Weber, KD1JV. It is currently being marketed by QRPKits. It has a programmable IF Offset that allows it to read the final frequency of the radio, regardless of the mixing scheme. It will display Mhz and Kilohertz (MM.kk), or Kilohertz down to 100 hz (kkk.h)

Construction started with placing a very small amount of solder paste on all of the pads. Some people say that you can just squirt out a string of paste across the tiny pads of the multi-pin devices, and they will suck up onto the pads when you heat it up. But that just didn’t seem right to me. So I painstakingly applied solder paste individually to each solder pad. I then placed the components with some tweezers for the bigger parts, and a wet toothpick for the smaller parts. Using the skillet and embossing gun method detailed on my post about the NorcalQrp Dummy load, it melted all the solder paste, and continued on with the few larger components.

Solder Paste Applied, and components placed

Solder Paste Applied, and components placed

Here is the underside of the LED Display Module. The leads have to be bent out at right angles to the bottom, so it can be soldered directly to the front side of the board.

Bottom of LED Display

Bottom of LED Display

And here it is with the leads bent out…

Leads bent out on first side

Leads bent out on first side

Aghhh! I can’t believe I did that… The instructions were explicit about making sure you get the LED module installed right-side-up. But I was so worried about getting the surface mount stuff right (this was only my second surface mount project) that I forgot to check. I didn’t realize anything was wrong until I fired it up, and just got some random segments lit up.

LED Display installed upside-down

LED Display installed upside-down

So I had to unsolder it from the board, which wasn’t easy since I had already mounted the Capacitor, Switch and Crystal to that side. I flipped it over and re-soldered it down. Then it worked fine.

I calibrated it by zero-beating its 10mhz crystal against WWV… Close enough for now.

Finished Digital Dial

Finished Digital Dial

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