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Søren Kjærsgaard2/2)I decided to test it with a 0dBm RF source through an isolator and it clearly reacts to the small amount of applied power, moving from 2480 Ohm down to 2438 Ohm. Any suggestions for more experiments? 🙂<a href="https://techhub.social/tags/rfengineer" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#rfengineer</a> <a href="https://techhub.social/tags/rfengineering" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#rfengineering</a> <a href="https://techhub.social/tags/electronics" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#electronics</a> <a href="https://techhub.social/tags/testandmeasurement" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#testandmeasurement</a> <a href="https://techhub.social/tags/sensorsunday" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#sensorsunday</a>

Søren Kjærsgaard1/2) A fellow <a href="https://techhub.social/tags/hamradio" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#hamradio</a> operator and electronics enthusiast brought me a vintage X-Band power sensor, thanks OZ1ETE 🙂It has a super sensitive NTC Thermistor, a tiny spherical bead, encapsulated inside a small glass tube. It’s by far the most sensitive Thermistor I’ve ever seen, just holding your hand in front of the waveguide flange, not actually covering it, will make it change slightly. <a href="https://techhub.social/tags/rfengineer" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#rfengineer</a> <a href="https://techhub.social/tags/rfengineering" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#rfengineering</a> <a href="https://techhub.social/tags/electronics" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#electronics</a> <a href="https://techhub.social/tags/testandmeasurement" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#testandmeasurement</a> <a href="https://techhub.social/tags/sensorsunday" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#sensorsunday</a>

Søren KjærsgaardIt’s <a href="https://techhub.social/tags/sensorsunday" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#sensorsunday</a> 🤩A field strength meter can be really handy when testing antennas and they’re simple to build: a couple germanium diodes, a capacitor, a good old analog uA meter and a potentiometer to adjust the sensitivity. This unit was just $20 and it seems they repurposed a PCB originally intended for some other application 🤷🏼‍♂️ 🙂To use it, start by adjusting the sensitivity to its minimum setting, key the transmitter at its lowest power (1W will certainly do) and walk along the antenna and measure the field strength along the wire or structure. I’ll do a future post demonstrating it on a trap dipole , W3DZZ style 🙂<a href="https://techhub.social/tags/hamradio" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#hamradio</a> <a href="https://techhub.social/tags/hamr" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#hamr</a> <a href="https://techhub.social/tags/antennas" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#antennas</a> <a href="https://techhub.social/tags/antennaengineering" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#antennaengineering</a> <a href="https://techhub.social/tags/rfengineer" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#rfengineer</a> <a href="https://techhub.social/tags/testandmeasurement" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#testandmeasurement</a>

Søren KjærsgaardIt’s <a href="https://techhub.social/tags/sensorsunday" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#sensorsunday</a> and <a href="https://techhub.social/tags/chipoftheday" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#chipoftheday</a> and here’s a real treat for you: The Burr Brown OPT-101 light sensor with built in amplifier, all in a clear plastic DIP-8 🥰Applying power, it reacts to the surrounding light and the PWM cycle of my bench LED strip became clearly visible, immediately. Its bandwidth is somewhat limited (20kHz), but it’s such a funny device that we should all have at least a couple, just because 👌🏻☺️<a href="https://techhub.social/tags/electronicsengineering" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#electronicsengineering</a> <a href="https://techhub.social/tags/electronics" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#electronics</a> <a href="https://techhub.social/tags/testandmeasurement" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#testandmeasurement</a> <a href="https://techhub.social/tags/hamradio" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#hamradio</a> <a href="https://techhub.social/tags/hamr" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#hamr</a> <a href="https://techhub.social/tags/engineer" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#engineer</a>

Søren KjærsgaardIt’s <a href="https://techhub.social/tags/sensorsunday" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#sensorsunday</a> and this weekend I finally got to use my DIY thermal chamber 😃 Along with a Fluke thermocouple meter it turned out really good 👍🏼 Doing temperature test on the 1M <a href="https://techhub.social/tags/vintage" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#vintage</a> reference resistor - it’s big and heavy, so I left it to soak at the wanted temperature for at least 8hrs, continuously monitoring chamber and device temperature. Testing at 10,20 and 40C, I found a slightly negative temperature coefficient, but still well inside the 0.02% specification.My measurements are a bit lower altogether compared with my initial test where I saw precisely 1M. This is due to coupling between the test wires, when entering the thermal chamber. It’s really hard to avoid, even giga-ohms in parallel, will affect the result.<a href="https://techhub.social/tags/testandmeasurement" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#testandmeasurement</a> <a href="https://techhub.social/tags/electronics" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#electronics</a> <a href="https://techhub.social/tags/metrology" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#metrology</a> <a href="https://techhub.social/tags/electronicsengineering" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#electronicsengineering</a> <a href="https://techhub.social/tags/engineer" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#engineer</a> <a href="https://techhub.social/tags/fluke" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#fluke</a> <a href="https://techhub.social/tags/sourcemeasureunit" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#sourcemeasureunit</a> <a href="https://techhub.social/tags/keithley" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#keithley</a> <a href="https://techhub.social/tags/keithleyinstruments" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#keithleyinstruments</a>

Søren KjærsgaardInspired by a Twitter dialogue, let’s launch some daily <a href="https://techhub.social/tags/electronics" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#electronics</a> tags to be used freely 👍🏼🤓Today is <a href="https://techhub.social/tags/waveformwednesday" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#waveformwednesday</a> and here’s how my mains grid looks - not quite a sine but that’s to be expected. Don’t ever, EVER, connect your scope input directly to mains - use a high voltage differential probe or a transformer, as shown here. I’m using the <a href="https://techhub.social/tags/quicktest" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#quicktest</a> switch, it’s a really handy way to control power to a circuit. It’s of British origin and comes with a standard 13A BS1362 fuse. I found that a bit high for my purposes, so I replaced it with a 5A, significantly limiting the available energy in case of a fault situation. Safety first always applies at the bench 👍🏼⚡️☝🏻So go ahead, use these tags freely, be inspired and show us your experiments 👌🏻🙂<a href="https://techhub.social/tags/electronics" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#electronics</a> <a href="https://techhub.social/tags/rohdeschwarz" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#rohdeschwarz</a> <a href="https://techhub.social/tags/micsig" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#micsig</a> <a href="https://techhub.social/tags/electronicsengineering" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#electronicsengineering</a> <a href="https://techhub.social/tags/engineer" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#engineer</a> <a href="https://techhub.social/tags/hamradio" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#hamradio</a> <a href="https://techhub.social/tags/measurementmonday" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#measurementmonday</a> <a href="https://techhub.social/tags/testgeartuesday" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#testgeartuesday</a> <a href="https://techhub.social/tags/waveformwednesday" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#waveformwednesday</a> <a href="https://techhub.social/tags/teardownthursday" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#teardownthursday</a> <a href="https://techhub.social/tags/frequencyfriday" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#frequencyfriday</a> <a href="https://techhub.social/tags/signalsaturday" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#signalsaturday</a> <a href="https://techhub.social/tags/sensorsunday" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#sensorsunday</a>

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