Electronics – Page 11 – AB4UG Radioblog

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.

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.

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.

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.

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.

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.

Return loss bridge

The initial version of the Etherkit HF return loss bridge. Pretty simple. Now I need to learn what it does and how to use it.

More workbench gear and parts

Thanks to Jason/NT7S for enabling my growing homebrew electronics ambitions. I now have a bunch of stuff to add to the workbench.

There’s this big bag-o-parts to augment the parts bin. It’s filled with resistors, capacitors, diodes, transistors, inductors, ICs and crystals.

He also sent along a first version of his HF return-loss bridge kit and an M³ frequency counter/power meter for the workbench. With the return-loss bridge, frequency counter/power meter, a signal generator and oscilloscope, Jason tells me I’ll be able to make all kinds of measurements for testing and characterizing circuits. I guess I’ll need to spend some more time with the Heathkit signal generator to see how operational it is. I’ll also need to pick up some BNC connectors and jumper cables.

Jason also recently acquired a couple of TI Tiva Launchpad boards, so I got his surplus TI Stellaris LM4F120 and MSP430 boards to play with. Not quite sure what I’ll do with them yet, but maybe they’ll push me to brush the cobwebs off the C I’ve learned.

I also received most of the components I’ll need to build some version of a sound card interface that I can use to connect to the radio for using digital radio modes. I think I’m going to have fun working on that project.