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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. In spite of the fact that there are some innovative designs on the market like building a relatively cheap amateur radio transceiver by using a microcontroller as part of the radio frequency circuits, I strongly believe that a “real” radio must have filters, mixers, amplifiers and other “old style” stuff.

Should you have any questions, comments or you would like to buy a radio kit, components or other material, please mail

peter(at)dk7ih.de !

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!

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Latest entries:

A 10-band shortwave radio with 10+ watts of output (Sep 2023)

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Issues and observations using the Si5351 clock oscillator in the VHF range

(Mar 11, 2023 )

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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!)

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More Amateur radio equipment

QRP-Transceivers/Two-way radios for SSB modulation

With analog VFO

• • • • • A mid-power portable/handheld SSB transceiver for 14MHz
        • Going back in time: “Old school” transceiver for 20 meters with 20 watts of output
        • A “lean design” SSB-Transceiver for 14 MHz with analog VFO

With digital VFO

Multiband

• • • • • • • • “Gimme Five” reloaded – A compact 5 band QRP SSB transceiver for 1.8, 3.5. 7, 14 and 18MHz
              • An experimental HF 6-band SSB transceiver for 1.8, 3.5, 7, 14, 21, 28 MHz
              • QRP SSB multiband transceiver (5 bands/10 Watts PEP) for 3.5, 7, 14, 21 and 28 MHz

Monoband

Handheld/”Walkie-Talkie”

• • • • • • • • • • A “Walkie-Talkie” SSB transceiver for 14MHz or higher rf bands (also available as kit!)
                  • A compact handheld QRP SSB transceiver for 14 MHz
                  • A mid-power portable/handheld SSB transceiver for 14MHz

Station transceivers

• • • • • • • • • • • 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

Test equipment

• • • A simple 2-tone-generator for testing the linearity of SSB transmitters
    • A Dual Audio Frequency Generator with 2 DDS modules
    • Cheap and dirty measurement of filter response curves

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)

• • • Das QRP-Baubuch (3rd edition, German language only, 1993)

Microcontroller related material

Digital radio frequency generation (DDS etc.)

• • • Programming the AD9834 DDS chip
    • A simple software to control the Si5351A clock generator chip (Version for STM32F4)

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

Scuba diving

• • • An open source dive Computer (Buhlmann ZH-16 algorithm)

Remote controlling, telemetry etc.

• • • A 433MHz RC unit for large scale model train locos (RFM12B)
    • Telemetry data transmission from stratosphere to ground control

My code collection on Github (Embedded C for AVR and STM32)

• • • https://github.com/DK7IH

Misc

• • Fake components – and how to recognize them