Your MultiMeter Might be Lying to You

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Your MultiMeter Might be Lying to You

Multimeters are indispensable tools when working on electronics. It’s almost impossible to build any but the most basic of circuits without one to test and troubleshoot potential issues, and they make possible a large array of measurement capabilities that are not easily performed otherwise. But when things start getting a little more complex it’s important to know their limitations, specifically around what they will tell you about circuits designed for high frequency.

The issue that often confuses people new to radio or other high-frequency projects revolves around the continuity testing function found on most multimeters. While useful for testing wiring and making sure connections are solid, they typically only test using DC. When applying AC to the same circuits, inductors start to offer higher impedance and capacitors lower impedance, up to the point that they become open and short circuits respectively. The same happens to transformers, but can also most antennas which often look like short circuits to ground at DC but can offer just enough impedance at their designed frequency to efficiently resonate and send out radio waves.

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Vacuum Tube-Making on the Comeback in the US

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American-made vacuum tubes are poised to make a comeback onto the market this summer.

As the rising cost of vacuum tubes manufactured mostly in China and Russia increasingly cramps audiophiles, musicians and others seeking a particular audio quality, one factory in the US southeast is preparing to bring tube-manufacturing back home.

With assembly line workers getting down to business inside his Western Electric plant in Rossville, Georgia, entrepreneur Charles Whitener expects to restore American-made vacuum tubes to the worldwide market in just a few months. According to reports on such websites as wired.com and audioexpress.com, Whitener's goal is to resume production of the single-ended triode tube known as the 300B, a design that dates back to 1938. His plant, known as the Rossville Works, is home to the Western Electric vacuum tube brand which Whitener bought in 1995 from AT&T.

This summer he expects to introduce a reimagined version of the audio vacuum tube known as the 12AX7, a dual triode tube commonly found in amplifiers for guitars. According to Wired.com, it will be the first US-made tube in decades and it is expected to be followed by numerous other US-made models.

FCC Takes a Deeper Dive into Satellites

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Having dismantled its International Bureau, the US Federal Communications Commission has instead created two new departments: the Space Bureau and the Office of International Affairs.

This is a move by the agency to position the US to take a leading role in global space technology. It also gives the agency what it hopes is a greater voice in handling space debris which has become an issue as more and more satellites’ orbits decay.

The talk has been all about wireless and internet and related uses but what is missing from this recent announcement is what this all means for amateur radio satellites. No one has made a statement from the FCC as to how the CubeSats and other ham radio satellites will be handled, if at all, by these new offices.

The departments are expected to coordinate their efforts in such areas as the 2023 World Radiocommunication Conference. The conference will take place in Dubai starting on 20th November 2023.