# Tag Info

4

One of the functions of an oscilloscope is actually to measure RF volts, just make sure to use the x 10 function to minimize loading on the circuit you are measuring, and keep in mind that some high impedance circuits will still be affected even if you use the x 10 function.

3

Maybe. If measuring a circuit output that expects a load impedance, such as a 50 Ohm coax or antenna, then to measure the RF voltage at that point with an oscilloscope, you should terminate that circuit output with the expected impedance (a dummy load), and measure the voltage waveform across that impedance load with a much higher impedance probe (x10 or ...

3

Think of the antenna as a whole as being many inductors in series along its length and along with that many capacitors branching off like a tree (capacitors in the air) going back to the "negative side", so parallel capacitors. The loading coil needs actual current to work with, the further up on the antenna that you mount it, the less current ...

3

First off, a 1 Watt transmitter puts 7.07 volts RMS across a 50 ohm load, or 10 volts peak. So most any diode detector circuit using a silicon signal diode (perhaps a 1n4148) would be plenty accurate for ham uses. For a 0.1 Watt QRP transmitter (3.16 volts peak), a schottky 1n5711 diode would still keep it accurate within 10%. If the voltmeter has a 10meg ...

2

Because ferrites aren’t marked, it is difficult to know what frequencies they work on. However, now we can use the popular NanoVNA along with free software (and Excel) to graph the unknown ferrite’s impedance over frequency. YouTube video by Fair-Rite Corporation, using a Nano VNA and software: https://youtu.be/KmKQibSDzqM (Sorry that more info from this can'...

1

Old skool basics: RBW sets detector time: 3 periods; there is a relation with the accuracy (exponential settling). RBW of 10 kHz requires about 300 uS for measurement time of level. RBW sets als maximum frequency step size: half the RBW, otherwise you miss power in-between points. For 10 kHz RBW the maximum step is 5 kHz. Number of steps for 30 MHz span is ...

Only top voted, non community-wiki answers of a minimum length are eligible