Welcome to my website on “Old School” QRP radios!
These sites deal with “hardware defined” radios. Although I think, that SDRs are a great invention, this website is dedicated to the “old school” style of building ham radio transceivers. That means using classical filter circuits, mixers etc.
Should you have any questions, comments or you would like to buy a radio kit, components or other material, please mail
Please keep in mind that the designs are free for non-commercial use and for educational purposes. Any commercial exploitation would violate this copyright. Thank you!
Issues and observations using the Si5351 clock oscillator in the VHF range
(Mar 11, 2023 )
VFO/LO for a multiband tranceiver project
Universal VFO with an Si5351 clock generator
Universal AD9951 DDS VFO module for QRP projects
“Walkie-Talkie” SSB transceiver for 14MHz or higher rf bands
Classical QRP Circuits – A collection of tested and proven modules for QRP radios
Module 1: SSB generator using MC1496N
Module 2: Transmit Mixer with the MC1496N IC
Module 3: QRP SSB PA with 10 Watts PEP
Module 4: Si5351 VFO module
Module 5: AD9951 VFO module
Module 6: Crystal controlled local oscillator (LO) (NEW!)
Module 7: LC tuned Colpitts VFO for 5 MHz (NEW!)
More Amateur radio equipment
QRP-Transceivers/Two-way radios for SSB modulation
With analog VFO
With digital VFO
- High performance transceiver for voice communication on 14MHz
- The “Cigarette Pack” Transceiver (14MHz, SSB, 4Watts PEP)
- The “Micro42” – Another “shirt pocket” SSB transceiver.
- The „Micro20 III“ – A Simplified Pocket Size SSB Transceiver for 14 MHz
- My 1st “Shirt-pocket” transceiver (re-engineered)
- An ultra compact QRO transceiver for 40 Meters with
Antennas and Tuners
- A semi-automatic antenna tuner for QRP use
- Reviewing and improving the semi-automatic antenna tuner
- The semi-automatic antenna tuner – Version 1b
- Improved matching for 20-meter-band rod antenna
- Mounting a rod antenna to a homemade handheld QRP transceiver
- An easy-to-build rod antenna for 14 MHz (20 meter band)
Literature by Peter (DK7IH)
Microcontroller related material
Digital radio frequency generation (DDS etc.)
Tutorials, Algorithms etc.
- Simple GPS-Decoder (NMEA) with STM32F4 using USART
- Tutorial: Register Programming of the STM32F4/ARM-Cortex-M4 Microcontroller
- Direct FM generation with fast MCU and parallel DDS
- Decoding time station signals (DCF77 etc.) with a microcontroller
- Interfacing colored LCD ILI9341 with 8-bit Microcontroller
- Decoding NMEA data from a GPS module with a microcontroller
- Interfacing an LCD12864 (ST7920 controller) to a microcontroller
- Interfacing an analog temperature sensor to an AVR microcontroller
Remote controlling, telemetry etc.
My code collection on Github (Embedded C for AVR and STM32)