Skip to content
Badscrew Projects Badscrew Projects

Making and hacking software and hardware. Also making music and art.

  • English
  • Français
  • Guitars
  • Hardware
  • Software
  • Gardening
  • Cocktails
  • About
  • Privacy Policy
Badscrew Projects
Badscrew Projects

Making and hacking software and hardware. Also making music and art.

Universal Radio Tester

Badscrew, September 7, 2021July 15, 2023

This simple device is a basic signal generator that can be used to debug audio and AM radio frequency circuits. It produces a (roughly) 1 kHz periodic wave output that has enough harmonic frequency content to go into high MHz range – this will make the signal audible even when injected into RF and IF radio circuits.

The schematics is based on a simplest possible two-transistor multivibrator that can be powered by one 1,5 battery (AA or AAA) but will also work fine with a higher voltage source, for example a 3,6V lithium coin cell. It draws around 300 mA at 1.5V. The components values can vary, also pretty much any pair of low power transistors will work. In case of PNP transistors, the battery should be flipped (+ as the ground and – as the power rail). It should start working right away and doesn’t require any tuning.

The output waveform and frequency will vary depending on the tested circuit impedance, without the load it will be similar to this:

Github source: https://github.com/badscrew/RadioTester

I simply soldered mine on a perfboard and it proved itself very useful:

Other related posts:

Hardware Tools Electronics

Post navigation

Previous post
Next post

Related Posts

Audio

3. Dead Kings bass effects pedal – EQ

September 4, 2021July 15, 2023

This is the 3rd post in the Dead Kings preamp series. Now to design the EQ module! My initial idea was to create a circuit inspired from the classic tube bass amplifiers, like Ampeg Portaflex or SVT. I did some research and got somewhat carried away, so the circuit I…

Read More
Audio

Bad Screamer: adding a mid-boost

February 4, 2023July 15, 2023

All articles from the Bad Screamer series Thinking about this a little bit, there’s a way to act on the frequency response using a little more complex emitter negative feedback circuit. Did a bit of play with the sim and various values, I can create a mid bump this way…

Read More
Hardware

Minitel

June 22, 2021July 15, 2023

Hey, look what I’ve got, it’s small, cute and it works. Well, the Minitel network is no more, but I have some interesting ideas (and three of these!) Will speak about this more in near future!

Read More

Leave a ReplyCancel reply

art badscreamer ballpoint pen Beirao Bitter Blogging Cachaça Campary cherries DeadKings Electronics Gin ginger beer gold-o-caster Gorria Grenade guitar Harley Benton hollowbody ibanez lemon lime meme Mint overdrive peppers picks pink red bitter Review rum salsa salsa verde sketch Strings tomatillos tomatoes Tonic tree Villa Cardea Walnut Whisky Wordpress

©2025 Badscrew Projects | WordPress Theme by SuperbThemes