Sound card interface project

The next project on the workbench is this digital VOX sound card interface by Skip Teller/KH6TY from the March 2011 QST.

It’s a simple enough looking project, and I’m pretty sure that between what I had before and what Jason/NT7S sent me, I’ll have all the parts that I need. I might need to go shopping for a connector for the radio end of the interface though.

My plan is to build it on a piece of the perfboard I picked up at Radio Shack the other day. I’ll have to take the schematic and translate that into a circuit layout for the perfboard. Should be a fun exercise.

Heathkit IG-102 capacitor

The Heathkit IG-102 signal generator has this big 20 μF 150VDC electrolyic capacitor that has 2 leads on the positive side and one lead on the negative side. It looks like an axial capacitor, but I’ve never seen one with two leads on one side before.

20 uF capacitor
20 μF capacitor
20 uF capacitor
20 μF capacitor

Although it doesn’t seem to be showing any signs of failing, given the unknown age of the signal generator I thought it might be a good idea to replace it with something new. I’m thinking I should replace it with two caps, one for each lead on the positive side. Don’t have any axial caps in the parts bin, but there are plenty of 20 and 22 μF radial electrolytic caps. No new 20 μF caps though.

Might have to go shopping.

Heathkit IG-102 surgery

Did some surgery to replace the old connectors on the Heathkit signal generator with BNC connectors.

Heathkit IG-102 old style connectors
Heathkit IG-102 old style connectors

I thought it might be a bit of a challenge, but turned out easier than expected. The center of the connectors turns out to be just a hole/eyelet, so a bit of heat on those center contacts to melt the solder was enough to free the wires connected to them.

Behind the connectors
Behind the connectors
Behind the connectors
Behind the connectors

Once that was done, it was a simple matter to remove the connectors and replace them with a couple of BNC connectors. Solder the wires into the center connector of the BNC and done! While I was at it, I also replaced the yellow 0.01 μF capacitor with a new one.

New BNC connectors
New BNC connectors
New BNC connectors
New BNC connectors

Looks pretty spiffy and modern now with the BNC connectors. Still not entirely sure if it works or how well it works, but at least now it’ll be easier to connect the signal generator to stuff.

Heathkit IG-102 with BNC connectors
Heathkit IG-102 with BNC connectors

Radio Shack deals for builders/makers

If you happen to be near your neighbourhood Radio Shack, stop in and you might find some good clearance deals. Look for the items with blue or tan on the price tags.

I stopped in today to look for an audio transformer to build a sound card interface for the radio, and ended up coming out with a couple pieces of 4.5×6″ perfboard, a resistor component pack, and a capacitor component pack that were on clearance. The perfboard was less than $1.50 each, and the resistor and capacitor component packs were $7 and $6 respectively. The component packs are normally in the $25 range I think. Although I’ve already got plenty of resistors and capacitors, it was really the boxes that I wanted. I think of it as a two good component boxes that come with free resistors/capacitors.

My store also had a few Arduino shields that were clearance marked as well.

Might have to pay a visit to some of the other Radio Shacks in the area.