Lab Notes

Chronological documentation of experiments, measurements, and discoveries in RF and electronics.

Weinschel attenuator

step-attenuator

Weinschel step attenuator

RF power meter design

rf-power-meter

RF power meter design and vibe coding

A double balanced diode ring mixer

Not calculating because rftk has been taken off CRAN (per 2025-12-28)

Oscillator, 10MHz, 74HC04

It should be possible to use an inverter to create a simple oscillator, and with a crystal it should be possible to set its frequency. This is a design that is everywhere:

Rebuild of RF power tap

Last week I built a 40 dB tap as a proof of concept, but two things held me back from declaring a full success:

0dBm reference revisited: LTspice simulations

A while back I built up a circuit intended to prototype a leveling circuit that could program the output level using a dc control voltage. Hans Summers showed such a circuit …

Small-signal broadband 1:1 transformer

I’ve been thinking about an application where I want to provide transformer-isolated outputs (a 10MHz reference distribution amplifier). But I really find working with…

RF power tap

I have thought about what I need to do to monitor my own transmission on an oscilloscope - or possibly a spectrum analyzer; also it would be nice to have the possibility of…

RF sense

As part of another circuit I’m trying to design, I would like to have a high impedance detection of whether there is RF on the wire (this would be for a lab 10MHz…

Experiments with a directional coupler

station-power-meter

It has been a radio weekend. Not only have worked a bit of HF (including Morocco and the Canary Islands!), but I have finally gotten around to winding transformers for the…

A broadband (HF) amplifier, a step towards a logging power meter

I want to make a meter for my amateur radio station that can log transmitted power, swr, and the transmitted frequency to a file. For the detector, I’ll use a directional…

Antennas on balcony

Using good weather to install an antenna on balcony

Are my 10MHz Oscilloquartz oscillators too old?

I have 2 10 MHz Oscilloquartz 8863 modules (rebranded as UCT) that I have bought used from ebay with an intention of building either a better internal reference for my…

Experiments with Kjell ferrites

Experiments with Kjell ferrites

10MHz Colpitts oscillator

10MHz Colpitts oscillator

Attempting a 0dBm reference

0dBm

Attempting a 0dBm reference