High Schoolers Build a Radio Receiver

Students learn to melt solder, layout PC boards, use tools, and troubleshoot by building an analog, discrete component receiver.

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At a local high school, students get a lot of exposure to digital high tech, but there was a gap in the area of analog electronics. Radio amateurs were asked to teach students how to build something analog. A direct conversion receiver was chosen: it had the right mix of simplicity and usefulness. The instructors decided to make this a true homebrew project: students would build the four stages of the receiver on copper-clad boards using the Manhattan technique. The ultimate in open-source projects, all components would be discrete and analog (no ICs). The students would understand the purpose of every part in the receiver. The students learned a lot about analog electronics, PC board layout, and how to build things. They can now grab a schematic, gather parts, and build circuits. Learning-by-building is a powerful technique. We hope others around the world will use this receiver project to re-engineer the teaching of electronics. Others are already doing this.

We went with just four boards, four subcircuits:  Bandpass filter.  Mixer.  RF Oscillator,  Audio Amplifier. 

Understanding these four circuits allows students to understand almost all RF devices. 

Circuits were chosen for their simplicity and understandability:  Nothing exotic or overly clever.  

Students were required to actually BUILD the circuits.  

This was a challenge.  This was not easy. 

This was NOT a kit-build.  Students would layout their own boards and acquire parts from a central parts source. 

The receiver they built is a real receiver, capable of real long-distance communications.  It has been used on the airwaves in a two-way contact. 

Prior to this build, most of the students obtained their amateur radio licenses. 

This build project was part of a larger global effort:   There were similar group builds in Hyderabad, India and Munich, Germany.   Radio amateurs as far away as Australia helped build and test the receiver circuit prior to the project. 

                                        Students in Hyderabad India with the receivers they built

About 28 blog posts describing the details of this project can be found here:

Design Decisions in the High School Direct Conversion Receiver.docx

Design Decisions in the High School Receiver Project. Why we did it this way.

document - 15.29 kB - 05/29/2023 at 13:10


TJ DCR PO Worksheet - BOM.xlsx

DCR Bill of Materials - quantities for 15 complete receivers with spares

sheet - 19.19 kB - 04/25/2023 at 11:41


TJ DCR Mixer Build Instructions.docx

Building the Mixer - Step by Step

document - 1.17 MB - 04/25/2023 at 11:36


TJ DCR BPF Instructions.docx

Building the Band Pass Filter - Step by Step

document - 707.71 kB - 04/25/2023 at 11:36


TJ DCR Audio Amp Instructions.docx

Building the Audio Amplifier - Step by Step

document - 1002.77 kB - 04/25/2023 at 11:35


View all 25 files

  • 1 × See BOM spreadsheet under Files

View project log

View all 7 instructions

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Dean Souleles wrote 06/07/2023 at 13:27 point

This is intentionally an analog electronics project, not a programming project or even a digital electronics project.  The students have many outlets for those skills including robotics and even a cube sat project.  We chose to have them build an all analog, discrete component receiver expressly to provide the students a foundation level understanding of RF engineering concepts.   It is also why we chose to use large, through-hole components, resistors, capacitors, transistors, diodes, and yes even toroid transformers that the students wound themselves.  Every step in the process - including the decision to use Manhattan style construction was intended to teach and reinforce fundamental concepts like the difference between and inductor and capacitor or the importance of a good ground plane when working with RF circuits.  The students were able to see the shape of the filter on a VNA and gain an intuitive understanding of what happens when they compressed or spread the turns of the transformer - changing the inductance.  As they built the analog variable frequency oscillators, they were able to experience directly what it means to have a resonant tuned circuit.  In the audio stage they learned why layout is important and how amplifiers can easily become oscillators if you are not careful.   We are working from the principal that there is an intuitive level of understanding that can be gained from this kind of hands-on work that you simply don't get from a software project. And this intuitive level of understanding will benefit them as they go on to bright technical careers in an all-digital world.  And they will have the advantage of having, at least once, built something complex and technical from scratch, where they can identify the purpose and function of each and every component in the circuit.

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Peabody1929 wrote 06/05/2023 at 21:24 point

During my 35 years in the computer industry I never built an analog band pass filter.  In the next 35 years, the students will build digital filters or  write code to implement a band pass filter.  That will be a 2056 skill instead of a 1956 skill.

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bill.meara wrote 05/26/2023 at 19:28 point

On May 16, 2023 Ashhar Farhan visited the High School and spoke to the students about Cubesats and about the benefits of building your own radio gear.  (He led a similar direct conversion receiver project in Hyderabad, India.)  A description of Farhan's visit to the school, along with an audio recording of his talk, is available here:

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bill.meara wrote 04/25/2023 at 13:23 point

One other thing:  We have been pleased to see the gender stereotypes about radio and electronics fading away rapidly in this project.  About half of the students are girls.   We notice no gender differences in this group.  

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bill.meara wrote 04/25/2023 at 12:19 point

To add some fun to the project (and to provide an incentive for moving forward) we gave prizes to whichever team first successfully completed a board.   For example, the team that completed their first bandpass filter (a board that required students to wind two toroidal transformers) won the coveted "Torry"  (like the Emmy or the Tony, but more techy).  You can see the Torry here:

The students like the award program, and it helped them follow our advise to "make haste slowly."  In other words, get it done, don't dawdle, but try to get it right. 

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bill.meara wrote 04/25/2023 at 11:25 point

Global (and especially South Asian) influence:  Many of the students are the children of immigrants, many from South Asia.  We think it was very positive that one of the main inspirations for this project came from India.  On our first visit to the school, we brought with us a direct conversion receiver that had been inspired by one built by our friend Farhan in Hyderabad as part of an effort to help a cousin in an EE program:

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bill.meara wrote 04/25/2023 at 11:00 point

A reward offer!   Our friend Walter KA4KXX has offered a $500 reward for the first student to build a simple transmitter and check into the early morning Florida sunshine net.  This is possible for students with the receiver and with their current ham radio license privileges. 

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bill.meara wrote 04/25/2023 at 10:51 point

An Australian build of our receiver:

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bill.meara wrote 04/25/2023 at 10:50 point

The first ever two wat radio contact made using this receiver (and a VERY small transmitter):

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bill.meara wrote 04/25/2023 at 10:47 point

A very similar project in Hyderabad, India:

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