SIGNAL GENERATORS — PART 2

Time to get our "freq" on.

Let’s talk about frequency synthesizers — the king of signal generators — as well as several other topics applicable to all high quality signal generators.

BUILD AN ELECTRONIC LOCK

This design uses an inductance coil.

Here’s a simple and inexpensive electronic key system you can incorporate into various projects that can be built with or without a microcontroller.

BUILD A 50 MHz DIPOLE OUT OF CRUTCHES

Just as other sculptors are blessed with the vision to see their works of art hidden in wood and marble, I have developed the ability to see antennas hidden in metal.

Over the last 45 years, I have built dipoles, ground planes, J-poles, quads, yagis, quagis, delta loops, and long wires. In addition to the traditional copper wire, I have cobbled them together using EMT and rigid aluminum conduit; copper, aluminum, and stainless steel tubing; brass welding rods; and even barbed wire. I have also used antenna tuners to load up bedsprings, fences, house wiring, abandoned telephone line, umbrellas, farm wagons, aluminum gutters, and tin roofs.

JUST IN TIME PARTS VS. THE JUNKBOX

Cleaning out my workshop reminded me of when I first started my journey in electronics.

Back then, tubes were still available at RadioShack. My first ham radio transmitter — a HeathKit DX-60B — used a 6146B tube final amplifier (power amplifier), in part because it was inexpensive and readily available. I had a junkbox with a few dozen tubes, a pound or two of discrete resistors and capacitors, and some miscellaneous hardware. With that, I could repair just about any TV, receiver, or transmitter that I came across or wanted to modify.

SIGNAL GENERATORS — PART 1

Let’s take a close look at these essential devices.

Signal generators are devices used to make the signals used in testing and troubleshooting of radio receivers and other circuits, so are of primary interest to almost everyone interested in electronics.

THE QUANTUM INTEGRATION ECOSYSTEM — A REVIEW

Simplify your IoT designs.

Embedded engineering is about burying a microcontroller inside a product to turn an everyday object into a smart object. When the smart object is also connected to the cloud, it’s instantly an Internet of Things (IoT) device. Quantum Integration recently introduced a product family designed to create IoT hardware applications quickly and easily. I had a chance to play with an initial release of their starter kit. Once I got over the initial learning curve, I was able to build two simple IoT prototypes to demonstrate cloud connectivity in about five minutes. Here is my experience.

BUILD THE MEMO_BOX

Never forget to bring your phone or keys (or ?) with you with this fun device.

Wouldn’t it be handy if you remembered to bring everything you need when you leave home without having to remember to remind yourself to remember? Well, the MEMO_BOX is just what you need! It will alert you with custom messages with its motion detector when you pass by it when you leave your house. Plus, you can use the motion detector to do other things like set off a recording of spooky sounds to delight trick-or-treaters when they come to your front door.

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AC VOLT/AMP METER WITH WEB INTERFACE

Self-contained volt/amp meter that displays the values on a webpage via a Raspberry Pi.

Work areas usually have multiple power strips ganged together and connected to the same outlet. Various devices are connected to these strips, including computers, lights, coffee pots, space heaters, etc. Environmentally conscious persons ask, “How much power does my work area consume?” Safety conscious persons ask, “Am I overloading my circuit?” Calculating the answers requires two basic measurements: the voltage supplied to the circuit, and the amperage consumed by the circuit. Measuring AC voltage and, particularly, amperage with a multimeter is a potentially dangerous diagnostic for laypersons. Wouldn’t it be nice to have a self-contained volt/amp meter that displays the values on a webpage?

BATTERY PACK FAILURE MODES I HAVE KNOWN

It is memory effect or something else?

Keeping your batteries ready for action in your ham radio hobby is something we all have to deal with. How much does “memory effect” come into play with recharging? Does it really exist? Let’s look at some different failure modes and what might really be behind them.

REMEMBERING THE CRYSTAL RADIO

Reminiscing about the good times that crystal radio sets provided.

In this article, I’d like to share how the primitive crystal sets of the ‘50s and ‘60s worked and hopefully stir some distant memories for those of you who also built one of these mysterious listening devices. I also hope that you’ll consider introducing your kids and/or grandkids to the world of crystal sets.

THE SMITH CHART

Unravel the mysteries of transmission lines with this unique chart.

The Smith Chart turns the complex mathematics of transmission lines into circles and arcs that unlock the mysteries of SWR, stubs, matching networks, and a whole lot more. It’s an amazing tool that brings the arcane math of transmission lines to visual life so you can understand them.

C PREPROCESSOR REDUCES DEBUG HEADACHES

Take advantage of C preprocessor operations.

In my experience, few hobbyists or experimenters take advantage of C preprocessor operations. You’ve probably seen preprocessor directives such as #include <stdio.h> or #include "servo.h"among the first lines in programs. However, they are not part of the C language. When you compile a program, it first goes through a preprocessor that handles housekeeping tasks such as including files that operate a peripheral or that provide a function such as printf. This tutorial will show you how to take advantage of this.