build-your-own-mini-fm-transmitter

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Build Your Own 
Mini FM Transmitter 


i 
| K) 
A 
Tt 


other networks for everyone 
by libi rose striegl (KROSES) & Lori Emerson (KFOLCB) 


Build Your Own 
Mini FM Transmitter 


OTHER NETWORKS FOR EVERYONE #1 
www.othernetworks.net 


by libi rose striegl (KROSES) & Lori Emerson (KFOLCB) 


a MEDIA ARCHAEOLOGY LAB//OTHER NETWORKS publication 


table of contents 


0.0 introduction 


01 What are Other Networks and Why Do We Need 


Them? 
0.2 Micro-Broadcasting as an Other Network 
0.3 Simplifying "the simplest radio broadcaster" 
0.4 Sources 
1.0 common electrical terms 
2.0 unit symbols and abbreviations 
3.0 circuit diagram 
3.1 Circuit Diagram Symbols 
4.0 materials 
41 Components 
4.2 Component Descriptions 
4.3 Tools 
4.4 Space Recommendations 
5.0 skills rundown 
5.1 Using Wire Cutters & Strippers 
5.2 Breadboarding 
5.3 Soldering 
6.0 initial preparations 
6.1 Making the coil 
6.2 Preparing the copper board 
70 assembly instructions 
71 Breadboard Assembly 
7.2 Soldered Assembly 
7.3 Operating the Completed Radio Transmitter 
74 Troubleshooting 
8.0 acknowledgements 
9.0 bios 


23 


25 


32 


37 


40 


54 
55 


0.0 
introduction 


0.1 What are Other Networks and Why Do We Need Them? 


It is no longer debatable: the network we call "the 
internet" is not the network we want nor the network we 
deserve. Over the past thirty years or so, the Web has 
unquestionably devolved into the only network most of us 
know about and therefore it’s also one that most of us accept 
will ruthlessly track, surveil, and, in Cory Doctorow's words, 
increasingly become a place of "enshittification." The Web is 
also now one of many networks--including Bluetooth, Wi-Fi, 
and cellular--we have little to no sense of how it works. How 
many everyday users know that the Web is only one of many 
networks that make up an internet we call "the internet"? Or, 
how many know that radio is integral to nearly every network 


we use? How many even know how radio waves work? 


“Other Networks," then, is a cluster of projects | have been 
working on for some years, often in collaboration with the 
irreplaceable libi striegl, to uncover, document, archive, and 
experiment with networks that existed before the internet or 
networks that currently exist outside of this internet. The goal 
of these projects is not only to significantly expand the 
historical record. The goal is also to make this knowledge 
about other networks accessible so that we may begin to 
reimagine what might be possible in the future. What 
networks can we bring back to life? What networks can we 
create? What networks are sustainable over the long term? 


What networks can exist within a non-commercial, 


cooperative context? 


In this spirit of accessibility, especially for those with no 
background whatsoever in electronics or radio, this pamphlet 
is the first of many to come in a series we call "Other 
Networks For Everyone." While there are many possible 
iterations of other networks that are relatively easy to build, 
we have become increasingly convinced that we haven't yet 
begun to tap the potential of amateur radio. Since its 
inception in the early 20th century, nearly all of the discourse 
in and around amateur radio has been dominated by a 
forbidding aura of expertise that seems intent on making 
radio as mysterious and as inaccessible as possible. One 
could easily say that a radio priesthood laid the groundwork 
for what Byte magazine called in 1976 the "software 
priesthood"--a movement in computing that encouraged 
users to stop opening up their machines to understand how 
they work and instead treat them as if they're simple, 
household appliances that one need not understand. 


0.2 Micro-Broadcasting as an Other Network 


Coincidentally or not, at the same time as this "software 
priesthood" emerged in the 1970s, a movement began in 
Europe toward experimenting with micro-broadcasting. 
Microbroadcasting' is often used interchangeably with 
‘micro-radio, 'miniFM', and sometimes even ‘free radio’. These 
are a collection of practices involving the use of a low power 
transmitter (either as an aesthetic or political choice or out of 
necessity) over a limited distance and thus reaching a limited 

2 


number of people. It is also considered a type of "community 
media" because of its local and non-commercial nature. 
Given the low power (as much as 100 watts but often as low 
as 1 watt) and short distances involved (as much as five 
kilometers from the transmitter but often much shorter), 
microbroadcasting can be both unlicensed and legal. 
However, regulations determining the legal status and power 
of micro-broadcasting vary significantly over time and from 
country to country; if national regulatory bodies prohibit 
individuals from transmitting to their local community, 


microbroadcasting may turn into pirate radio. 


The fact that regulatory bodies determine whether and 
how micro-broadcasting is legal means it is not a practice 
determined strictly by the constraints of one's transmitter. 
Rather, as Tetsuo Kogawa writes in "A Micro Radio Manifesto," 
"micro means diverse, multiple, and polymorphous. If micro 
does not mean small in physical size, then even physically 
bigger radio station [sic] could become micro. Micro radio is 
an alternative to mass medium and global communications 
that could cover the globe with the qualitatively same and 
patterned information." Microbroadcasting is therefore 
primarily a social practice aimed at providing diverse points 
of view while also resisting the commodification of these 
points of view and thus its origins can be traced to specific 
forms of media activism rather than, for example, early 
wireless radio experiments with low power over short 


distances. 
Based in Bologna, Italy, and lasting from 1976 to 1981, the 


3 


unlicensed radio station Radio Alice was likely the first 
instance of microbroadcasting as defined above. Even 
though it was referred to as "free radio" and pre-dated the 
emergence of the term "microbroadcasting," its main 
founders (students/activists Franco "Bifo" Berardi, Maurizio 
Torrealta, Filippo Scdzzari, Paolo Ricci, and Carlo Rovelli) 
essentially envisioned Radio Alice as a conscious micro radio 
experiment that sought to distribute control of the airwaves 
across many small transmitters as a way to flatten hierarchies 
between sender and receiver, embrace localism, and use art 


to unsettle if not unseat capitalism. As the editors of the 


Toronto-based magazine The Red Menace described it in 
1978, "Radio Alice broadcast news of the events as they 
occurred, often by airing telephone calls from militants who 
described events, called for assistance in a given sector, and 
reported police movements. The station was twice raided 
and closed down by police, but resumed broadcasting by 
switching locations and resorting to a transmitter powered by 


a car battery." 


A few years later, in the early 1980s, Tetsuo Kogawa 
introduced free radio to Japan, calling it "miniFM" as he led 
the way to hand-building tiny FM transmitters that used less 
than a hundred milliwatts and only had a half mile radius. The 
term "micro-radio" or "micro-broadcasting" then emerged in 
the U.S. in 1983 in the wake of the police beating African 
American Dwayne Readus, who later changed his name to 
Mbanna Kantako, in a public housing development in 
Springfield, Illinois. Kantako first created the Tenants Rights 


Association (TRA) and, to make sure the TRA could reach as 
4 


many residents of the development as possible, he also 
created radio station WTRA using a one watt transmitter and 
broadcast from his living room. In 1988, WTRA became Zoom 
Black Magic Liberation Radio then Black Liberation Radio 
followed by Human Rights Radio. 


0.3 Simplifying "the simplest radio broadcaster" 


As we learned more about micro-broadcasting and the 
untapped potential of amateur radio, we eventually realized 
that, if we wanted to begin the slow, arduous work of getting 
others involved in probing the limits and possibilities of radio, 
we needed to get licenses ourselves. We then spent several 
months attending an online class aimed at increasing the 
number of women and people of color with amateur radio 
licenses--a class which we appreciated but which we found 
was still unwittingly geared to those with an engineering 
background. After receiving our licenses in January 2023, we 
resolved to teach classes and workshops for anyone outside 
of engineering in a way that explained electronics and radio 
from the ground up and that, ideally, made it easier to get 
licensed. 


Fortuitously, we had the opportunity to test run a radio 
workshop in May 2023 when Darren Wershler invited us to 
help teach a graduate seminar at Concordia University 
(Montreal, Canada) on maintenance, repair, and sustainability. 
The class met on Zoom for a week to discuss readings and 
we then met in person for a week to work on projects related 
to the theme of the class. libi and | volunteered to lead a 
project to give students the opportunity to build mini FM 

5 


transmitters by following Tetsuo Kogawa's instructions for "the 
simplest radio transmitter." What we discovered, however, was 
that the instructions were far from simple, especially for those 
who had no experience with electronics. Some of the 
problems that students encountered: the instructions did not 
include a schematic so much as they included a diagram 
that contradicted itself in places; the original circuit was for a 
transistor that is not readily available outside of Japan and 
the instructions for an alternative transistor were confusing; 
there were inconsistent values on resistors and capacitors 
and no clear instruction on how to determine appropriate 
substitutions; and, finally, it was not clear that the copper 
plates in the design needed to be insulated from each other, 
causing a short in the circuit. 


Once libi and | returned home, we spent the next six 
months crafting a new set of instructions for building a mini 
FM transmitter that builds on Kogawa's instructions and is 
even more clear, thorough, and accessible. libi did most of 
the writing, photographing, layout, and design and my role 
was to let libi know every time anything in the instructions 
was unclear and to suggest different wording. It was a 
painstakingly slow and incredibly rewarding collaborative 
process for us both. We hope this pamphlet encourages 
many others to feel emboldened to experiment with this 
powerful example of an other network that is for everyone. 


—Lori Emerson, December 2023 


0.4 Sources 


David J. Hess and Robert Gottlieb, Localist Movements in 


a Global Economy: Sustainability, Justice, and Urban 
Development in the United States (MIT Press, 2009); Tetsuo 


Kogawa, "A Micro Radio Manifesto," Polymorphous Space 
website (2002, 2006); Marco Briziarelli, "Tripping Down the 
(Media) Rabbit Hole: Radio Alice and the Insurgent 
Socialization of Airwaves," Journal of Radio & Audio Media, 
23:2 (October 2016); "Radio Alice: Radio in Action in Italy, The 
Red Menace 2:2 (Spring 1978); Tetsuo Kogawa, "Toward 


Polymorphous Radio," Daina Augaitis and Dan Lander Eds., 
Radio Rethink : Art Sound and Transmission (Walter Phillips 


Gallery, 1994); Lawrence Soley, Free Radio: Electronic Civil 
Disobedience (Routledge, 2018); Steven O. Shields and 
Robert Ogles, “Black Liberation Radio: A Case Study of Free 


Radio Micro-broadcasting,” Howard Journal of 


Communications 5 (1995); Andy Opel, Micro Radio and the 


FCC: Media Activism and the Struggle over Broadcast Policy 


(Praeger, 2004); Christina Dunbar-Hester, "Spectral Utopias: 
Community Radio in the United States, 1970 to Present," 
Historia Actual Online, 54:1 (2021); Christina Dunbar-Hester, 
Low Power to the People: Pirates, Protest and Politics in FM 
Radio Activism (MIT Press, 2014) 


1.0 
common electrical terms 


Active Component: 

An active component is any component which does not 
meet the definition of a passive component; it may supply, 
amplify, or control current within the circuit. 


Alternating Current: 

Abbreviated to AC, alternating current is the type of current 
that comes out of a wall socket. The flow of alternating current 
periodically reverses direction and changes its strength 
continuously over time. It is capable of being transmitted over 
great distances without dissipating, which is the primary reason 
for its use in the electrical grid. Many electronic devices 


convert alternating current into direct current for use. 


Ampere: 
Ampere, commonly shortened to amp, is the unit used for 


measuring electrical current. 


Antenna: 
A device for sending and receiving electromagnetic waves. 
An antenna of some form is necessary for any radio reception 


or transmission. 


Anode/Cathode: 

The anode is the positive terminal in a battery or power 
supply that electrons flow away from when a device is in use, 
while the cathode is the negative terminal where electrons flow 
towards, completing the circuit. 

8 


Breadboard/Breadboarding: 

A breadboard, sometimes called a solderless breadboard, 
is a re-usable tool for building circuits. It is useful for 
constructing and testing circuits without permanently fixing 
components together. 


Capacitance: 

Capacitance is the capability of a material object or device 
to store electrical charge. The unit used to measure 
capacitance is the farad. 


Conductance/Conductivity: 
Conductivity represents a material's ability to conduct 


electrical current. It is measured in siemens per meter. 


Direct Current: 

Abbreviated to DC, direct current is the type of current that 
comes out of a battery, a rechargeable power bank, a solar 
panel, a USB wall plug, etc. The flow of direct current is always 
in the same direction and at the same strength, which is why 
many electronic devices convert power from AC to DC for use. 


Electrical Charge: 

The physical property of matter that causes it to experience 
a force when placed in an electromagnetic field. Electrical 
charge can be positive, negative or neutral, generally 
determined by the balance of protons and electrons at an 
atomic level. Positive charges repel positive charges, negative 
charges repel negative charges, and positive and negative 
charges attract each other. Neutrally charged matter does not 


experience force in an electromagnetic field. 


9 


Electrical Circuit: 

Generally shortened to circuit, an electrical circuit is a 
network of electrical components in a closed loop wherein 
current has a return path to the power source. In a circuit like 
the one we build here, where electrical power is supplied by a 
battery, the current travels out from the positive side, through 
the components in the circuit, and back to the battery via the 
negative side. 


Electrical Component: 

An electrical component is a general term for any part of an 
electrical circuit. Components are often described as "through- 
hole" or "surface mount", which refers to their construction and 
to the way they are attached to a printed circuit board (PCB). 
Through-hole components have legs or leads; they are 
attached to a PCB by putting those legs or leads through the 
metal-ringed holes and soldering them in from the other side. 
Surface mount components are placed on metal pads on the 
PCB and soldered down from the same side, often by heating 
the solder using an oven instead of a soldering iron. 


Electrical Conductor: 

A conductor is an object or type of material that allows the 
flow of electrical current in one or more directions. Metals are 
common conductors, such as the copper or aluminum used to 
make most wires. Water, unless it is absolutely free of any 
impurities like dissolved salts or metals, is also a conductor. 
Because organisms have bodies that are largely water-based, 
the bodies of plants and animals (humans included) conduct 
electricity to some extent. This is why it is important to protect 


10 


yourself from direct contact with anything carrying high voltage, 


like power lines or wall power outlets. 


Electrical Current: 

An electrical current is a flow of charged particles moving 
through electrical conductors or space. In the case of a circuit 
like the one we build here, the electrical conductors are the 
metals that make up the wires and other components. The 
charged particles are electrons. The unit used to measure the 
current is the ampere (generally shortened to "amp"). 


Electrical Insulator: 

An electrical insulator is a material in which electrical 
current does not flow freely. Insulators can be described as 
having very high resistance. Common insulators include 
ceramics, rubbers, plastics, paper, and glass. The deployment 
of these materials depends on many factors, including how 
much heat may be generated as a by-product of an electrical 
circuit. For example, while paper was once used as an insulator 
for electrical wiring in houses, paper is highly combustible and 
so while it resists electrical current it does not resist fire and 
can combust because of the heat generated as electricity 
flows through wires. 


Electrical Energy: 

Electrical energy is electrical potential put to use. It 
describes the forces that act on electrically-charged particles 
and the subsequent movement of those particles, often though 
not always in the form of electrons moving through wires. 
Electrical energy may be converted from electrical potential 
(voltage) into heat, physical motion, sound, light, radiation, etc. 

11 


Electromagnetism: 

Electromagnetism combines two fundamental forces: 
electricity and magnetism. Electricity involves tiny particles 
called electrons carrying electrical charge, which in turn 
powers devices, lights, and motors. Magnetism is the force that 
makes magnets attract or repel each other due to their 
magnetic fields. When electrons move while carrying electrical 
charges, they create magnetic fields. This connection between 


electricity and magnetism is what we call electromagnetism. 


Electromagnetic Field: 

An electromagnetic field is an invisible area around either 
electrical charges or magnets. Within that area, electrically 
charged particles or magnets can affect other objects without 
touching them. Whenever electrically charged particles move 
or whenever magnets are in action, a field is created. This field 
is responsible both for making magnets attract or repel each 
other and for transferring electrical energy. The transfer of 
electrical energy is particularly important because it allows us 
to use electricity to power devices. 


Electromagnetic Wave: 

An electromagnetic wave is a type of energy that travels 
through space. As such, electromagnetic waves can move 
without wires or other conductive materials. These waves are 
made up of two key parts: electrical and magnetic fields. 
When these fields interact and change, they create waves 
which can be used to carry energy that can be encoded as 
information. These waves exist naturally, for example as light 
from the sun. They can also be generated for various 


12 


purposes including radio waves used for communication, 


microwave ovens, and X-rays. 


Electromotive Force: 

Electromotive force (emf) is the energy that is transferred to 
a circuit, measured in volts. Emf can be produced through 
conversion from one type of energy to another, i.e. from 
chemical energy to electrical energy as with batteries, from 
mechanical energy to electrical energy as with wind turbines, 
or from light to electrical energy as with solar panels. 


Electron: 

An electron is a type of elementary particle, and these 
particles make up everything around us. Electrons carry an 
electrical charge. When these charges move around inside 
conductive materials such as metals, they allow us to create 
and harness electricity. When these charges stay in place, they 


form the outer layer of atoms. 


Energy: 

Energy is any property that could produce a change when 
transferred to a physical system. We can often recognize the 
expenditure of energy in physical movement, heat, and/or light. 
While here we are generally talking about electrical energy 
generated by chemical reactions inside of batteries and radiant 
energy from electromagnetic circuits, there are many other 
forms including kinetic, potential, elastic, etc. All living 
organisms constantly take in and release energy. The unit used 
for measuring energy is the joule. 


Force: 

In physics, a force is an influence that can cause any object 
to change its velocity unless it is counteracted by other forces. 
In this definition of force, objects may be large like a vehicle or 
a planet or they may be invisible like a molecule or an atom. 


Ground/Earth: 

Ground or earth for our purposes refers to the common 
return path for electrical current back to the power supply. All 
of the components in a circuit have some connection to that 
return path, either directly or through another component. 
Ground can also mean the point at which voltages in a circuit 
are measured, or a direct electrical connection to the planet 
Earth. For example, if you plug something into a wall outlet 
using a 3-prong plug, if the house is properly wired that third 
prong will have a direct electrical connection to the Earth. This 
helps to prevent shock and electrical shorting. If you use a 2- 
prong plug, you have only connected to the common electrical 
return path for the house. 


Joule: 

The joule is the unit for measuring energy. A joule can be 
calculated in many ways because energy is a broad concept. 
For electrical energy, a joule is the amount of work required to 
produce one watt of power for one second. 


Leg/Lead: 

Leg and Lead are colloquial terms used interchangeably to 
indicate the wires or thin metal strips that are part of many 
electrical components and are used to connect those 


14 


components to each other or to circuit boards in the process of 


circuit building. These are more formally known as "terminals". 


Load: 

Load is the colloquial term for power consumption of a 
particular circuit or component, measured in amps and volts. If 
a component consumes either more volts or more amps than a 
power supply is capable of providing to a circuit, the 
component may not function properly or at all, or may damage 
itself, the other components in the circuit, or the power supply. 


Ohm: 

The ohm is the unit of electrical resistance. One ohm is the 
electrical resistance between two points on a conductive 
material when one volt of power is applied to those points and 
a current of one ampere is produced in the conductive 


material. 


Open Circuit: 

An open circuit is an incomplete electrical circuit, with no 
pathway between the terminals of the power source. An 
electrical project that does not work at all is often found to 
have an open circuit due to improper connections between 


components or wires that are not secured properly. 


Pad: 

Pad is a colloquial term used to indicate a flat metal surface 
on a PCB, or a pool of solder on a larger metal surface, and 
that serves as a place to attach electrical components. These 


are more formally known as "terminals". 


Passive Component: 
A passive component is a part in a circuit that consumes 


energy but does not produce it. 


PCB: 

Short for printed circuit board, a PCB is a layered substrate 
of copper and insulating materials used to connect electronic 
components to one another in a controlled manner. Rather than 
directly connecting components to each other, the PCB has 
metal-ringed holes and/or metal pads; these are connected 
internally by lines of copper that transmit current from one 
component to the next per the requirements of the circuit. 


Pigtail: 

Pigtail is a colloquial term for a plug or other electrical 
component that has a short length of wire already connected 
to it so that it's ready to connect directly to a project without 


any preparation. 


Polarity/Polarization: 

Polarity in electricity refers to the direction in which 
electrical current flows through a circuit or component. In a 
battery, charged particles exit through the positive/+ side and 
re-enter through the negative/- side. In a polarized component, 
current is only able to flow in one direction; attempting to apply 
current in the incorrect direction could result in damage to the 


component. 


Positive/Negative: 
Positive refers to the terminal where current is flowing out 


from the power source, negative refers to the terminal where 


16 


current is returning to the power source. Most of the 
components in a circuit will be connected to both the positive 
and negative terminals either directly or via the connections 
made with other components. Polarized components will 
always be connected so that their positive terminal is directed 
towards the positive terminal of a power supply and their 
negative terminal is directed towards the negative terminal of a 
power supply. If components are not properly connected and 
the current cannot pass from the power source's positive 
terminal through the circuit and back to the negative terminal, 
the circuit is either "shorted" or "open" and will not function. 


Potential: 

In physics, potential energy is energy held by an object 
because of its position relative to other objects, stresses within 
itself, its electrical charge, or other factors. That energy can 
then be released in various forms. For example, a battery holds 
chemical potential energy that can be released as electricity or 
heat, a balloon that has been rubbed on carpet holds electrical 
potential energy (static) that can be released as light, heat, and 
electricity, and a ball resting at the top of a hill holds kinetic 
potential energy that can be released as motion. 


Power: 

Power is the amount of energy transferred or converted per 
unit of time (measured in joules per second). Electrical power is 
the rate at which electrical energy is transferred by an 
electrical circuit. The unit for this measurement is the watt. 


Prototype: 

A prototype is a temporary or experimental construction of 
a circuit, machine, piece of software, etc. Prototypes can range 
from very rough to quite polished, but they are always a work in 
progress rather than a final version. 


Resistance/Resistivity: 

Resistance is the measure of a material's ability to resist an 
electrical current. A low-resistance material is generally a good 
conductor; a high resistance material could be a good 


insulator. Resistance is measured in ohms. 


Semiconductor: 

Semiconductors are materials like silicon or germanium 
whose conductivity is neither extremely resistive (like insulators 
such as glass) nor extremely conductive (like conductors such 
as copper or aluminum), and whose conductivity can be altered 
and controlled through chemical and physical adjustments. 
They are used in transistors and diodes, and depending on 
their properties they can be used to amplify and control power 
(like transistors), emit light (like LEDs or light emitting diodes), 
absorb or emit heat, etc. Semiconductor materials do occur 
naturally; however, most of the ones used in electronics are 


manufactured through various industrial processes. 


Short Circuit: 

A short circuit is an electrical circuit where the current 
travels along an unintended path with no or very low electrical 
impedance. Shorting can result in excessive current flowing 
through the circuit. The consequences can be minor, like a 


circuit not working at all or a component failing; or major, like 
18 


overheating, fire, and electrical shock. An example of a short 
circuit is when tree branches touch power transmission lines, 
allowing current to travel to the ground and often causing 
arcing, fires and power outages. 


Siemens: 
A siemens is a unit of electrical conductance, expressed as 
a ratio. One siemens is equal to one ampere per volt. 


SI Units: 

The international system of units, or Systeme International, 
is the modernized metric system. SI is a standardized system of 
units of measurement centered around seven basic units; it is 
also a system of recognized prefixes, abbreviations, and 
derived units. The seven units are the second for time, the 
meter for length, the kilogram for mass or weight, the ampere 
for electrical current, the kelvin for temperature, the mole for 
the amount of substance, and the candela for intensity of light. 
SI was initially established in 1960 by the General Conference 
on Weights and Measures and that body is responsible for 
continued updates and clarifications. It is used by most 
countries and in most scientific, technological and engineering 
fields. Most units expressed in this text are SI units; non-Sl units 
will be noted. 


Terminal: 

A terminal in electronics is the point at which a conductor or 
component comes to an end and may be connected to 
another conductor or component as needed. Pad, leg, and lead 
are some colloquial terms for types of terminal. 


19 


Volt: 

A volt is the unit of electrical potential. One volt is equal to 
the difference in electrical potential between two points on a 
conductor when the current is at a constant of one ampere and 
the dissipated power is one watt. 


Wait: 

The watt is the unit for measuring electrical power. It 
indicates an electrical energy transfer rate of one joule per 
second. 


Work: 

In physics, work refers to the effort or energy transferred 
when a force acts on an object and causes that object to move. 
That energy transfer is quantified in joules. It can indicate large 
energy transfers like the work of lifting a heavy box or pushing 
a car, or small energy transfers like the work of an electrical 
charge moving through a conductive material. 


20 


2.0 
unit symbols and 
abbreviations 


A: 
Ampere or amp. The unit used to measure electrical 


current. 


AWG: 

American Wire Gauge. À scale used to denote the diameter 
of wire in the United States. Can be confusing as the larger in 
diameter a wire is, the smaller the AWG number. Commonly 
encountered in, for example, ear piercing gauges. Outside the 
United States, international standard simply measures diameter 
in millimeters. AWG is not an SI unit. 


Q: 

Ohm, the unit used to measure electrical resistance. KQ 
indicates kilo Ohm, meaning that a resistor labeled as 10 kQ is 
equal to 10,000 Q. 

F: 

Farad, the unit used to measure electrical capacitance. This 
symbol is often seen paired with additional symbols, like mF, uF, 
nF and pF, which indicate the metric prefixes for numbers 


smaller than 1. 


m: milli, or thousandth. mF indicates millifarad, or 0.001 
farad (3 decimal places to the left of 1). 


21 


H: micro, or millionth. yF indicates microfarad, or 
0.000001 farad (6 decimal places to the left of 1). 


n: nano, or billionth. nF indicates nanofarad, or 
0.000000001 farad (9 decimal places left of 1). 


p: pico, or trillionth. pF indicates picofarad, or 
0.000000000001 farad (12 decimal places left of 1). 
V: 

Volt, the unit used to measure electrical potential. 
Commonly used to talk about a battery's "size", or how much 
energy it holds; for example, 1.5v batteries are commonly used 
in remote controls and 12v batteries are commonly used in 


Cars. 


W: 

Watt, the unit used to indicate the rate of energy transfer. 
Commonly used to talk about a light bulb's energy usage or a 
solar panel's power rating; for example a 40 watt bulb or a 400 
watt solar panel. 


22 


3.0 
circuit diagram 


23 


3.1 Circuit Diagram Symbols 


T Antenna 


HH Battery 


~} Capacitor (where two symbols are indicated, 
t+ either symbol may be used) 


F- Capacitor, polarized; the small plus symbol 
> indicates the direction of polarity 


À Capacitor, variable 
+ 


NN Coil or Inductor 


Ground 


œ Input 


t+ Resistor 
AW- 


) Transistor (NPN) 


24 


4.0 
materials 


4.1 Components 


1 radio coil (appx. 40cm length 24 AWG [.5mm] 
enameled copper wire) 


1 antenna (1.5'/50cm length speaker wire or other 
insulated wire, between 22 and 16 AWG) 


1 audio input (3.5mm TRS plug pigtail; preferably mono) 
1 9V battery connector 


1 piece copper clad board 
(between 2" x 3"/5cm x 7cm and 4" x 6"/10cm x 14cm ) OR 
1 breadboard & jumper wires 


* 1 BC337 transistor 


(BC337 is a common transistor and can be bought 
individually or found in most transistor kits; however, if you 
are unable to find a BC337 transistor, you can use 
references such as alltransistors.com to search for 
equivalents.) 


110 kQ resistor 
(see color band guide referenced in the “Component 
Descriptions” section to identify these resistors) 


1 22 kQ resistor 
1 470 Q resistor 


2 10nF ceramic capacitors 
(usually marked with "103") 


1 uF ceramic capacitor 
(usually marked with "100") 


1 1uF electrolytic capacitor 


1~10-20pF variable capacitor 
25 


4.2 Component Descriptions 


Antenna 


An antenna can be as simple as a length of wire and as 
complex as a multi-story radio tower. For 
our purposes, we'll be using a short 
length of wire. It acts as the interface 
between electromagnetic waves (radio 


waves) moving in space and electrical 


currents moving in circuits. In 
transmission, a radio transmitter generates an electrical current 
and supplies it to the antenna's terminals, and the antenna 
radiates the energy from that current in the form of 
electromagnetic waves. In reception, an antenna intercepts a 
radio wave in space and uses some of that wave's power to 
produce an electrical current at its terminals, and a radio 
receiver connected to that antenna can then amplify that 


current as sound or other signal. 


Audio Input 


An audio input or audio jack is any connector meant to 
connect to an audio device. In this case 
we will be using the plug end with a Tip- 
Ring-Sleeve (TRS) connector. TRS 
connectors come in various sizes, with 
the 3.5 mm and 6.35 mm (1/4 inch) 


versions being the most common. 


26 


Battery Connector 


À battery connector is a component that establishes an 
electrical connection between a battery 
and an electrical circuit. It typically 
consists of terminals or contacts that 
allow the flow of electrical current from 


the battery to the device, enabling the 


device to be powered or charged by the 
energy stored in the battery. They are available for all types and 
sizes of battery - we will be using one designed for standard 9 


volt batteries. 


Capacitor 


A capacitor stores electrical energy in an electrical field by 
accumulating electrical charges on two closely-set conductive 
surfaces that are insulated from each other by some non- 
conductive material. The conductive surfaces are called 
electrode plates and the non-conductive insulator is called the 
dielectric. We will be using three types of capacitor: ceramic, 
electrolytic, and variable. 


A ceramic capacitor is a non-polarized capacitor with a 
ceramic dielectric. They are the most 
common. The number marked on the 
surface denotes capacitance, generally in 
a common code but sometimes in a code 


particular to the manufacturer. The 


common code chart can be found online, 
and manufacturer specific coding will usually be included in the 
box if you purchase a kit. 

27 


An electrolytic capacitor is a polarized capacitor. The 
positive side or anode is made of a metal 
that forms an insulating oxide layer 
through a process called anodization. This 
oxide layer acts as the dielectric of the 
capacitor. A solid, liquid, or gel electrolyte 


covers this oxide layer, serving as the 

negative side or cathode of the capacitor. The capacitance of 
an electrolytic capacitor is printed on the side, often followed 
by 'v' and then another number. The number after 'v' indicates 


the capacitor's voltage tolerance. 


A variable capacitor is a non-polarized capacitor whose 
capacitance can be changed, either 
mechanically or electronically. They are 
sometimes referred to as "tuning 

€. capacitors" because they're often used to 
tune radios. These capacitors are not as 
easy to come by as the others, and 
generally need to be purchased individually. They come in a 


capacitive range, and are generally color-coded by the 


manufacturer. 
Coil 
A coil or inductor stores electrical energy in a magnetic 


field when electrical current flows through 
it. It is typically made of insulated wire 


© wound into a coil shape or wound around 
a core of some kind. You will be given 
instructions to make a simple coil. 


28 


Resistor 


A resistor is a 2-terminal non-polarized component that 
introduces electrical resistance into a 
circuit through its material construction. 
Resistors can be static, maintaining a 
basically stable resistance regardless of 


external conditions; or variable, with 


resistance that can be physically 
adjusted or that varies depending on environmental conditions 
such as light, heat, humidity, etc.. Light sensors, temperature 
sensors, volume knobs, light dimmers, etc. are all examples of 


variable resistors. 


Static resistors are identified based on how many ohms of 
resistance they provide, and they are marked according to a 
standardized system of 4, 5 or 6 colored bands. Most static 
resistor packs have an identification table included in the 
package, and there are many online resources for identifying 
resistors, including this one from the electronics supplier 
DigiKey: www.digikey.com/en/resources/conversion-calculators/ 


conversion-calculator-resistor-color-code. 


Transistor 


A transistor is an active electrical component used to 
amplify or switch electrical current. 
Transistors are composed of 
semiconductor material and have at least 
three terminals. The terminals are known 


as the base/gate, emitter/source, and 


collector/drain. When a small electrical 
29 


current is applied to a transistor's base/gate terminal it will 
either emit a much stronger electrical current from one of its 
other terminals (amplification) OR it will allow a stronger 
electrical current to pass from the collector/drain terminal to 
the emitter/source terminal (switching). 


There are two basic types of transistor (Bipolar Junction 
Transfer [BJT] and Field Effect Transfer [FET]), and a number of 
subtypes. The one we are using is a BUT transistor, and its 
subtype is NPN (Negative-Positive-Negative, indicating the 
polarity of its terminals). 


Wire 


A flexible strand of metal. We make reference to several 
types of wire: Jumper wire, solid core, and stranded core. 


A jumper wire is a means for quickly and temporarily 
moving electrical current from one 
place to another. In breadboarding, 
it's a length of wire fitted with either a 
plug or a receptacle on each end 
and it connects different parts of the 


breadboard electrically. You may have used a set of jumper 
wires or cables to restart a car after the battery died. 


Solid core wire indicates a wire that is insulated (usually in a 
sheath of plastic or rubber) with only a single strand of metal 
inside the insulation. 


Stranded core indicates a wire that is similarly insulated and 


contains many very fine strands of metal within the insulation. 


30 


4.3 Tools 


* Small coping saw OR strong kitchen shears OR craft knife 
(soldered version only) 


e Eye protection (required for soldered version, 
recommended for breadboard version) 


e Gorilla glue OR double-sided tape OR another adhesive 
suitable for metal (soldered version only) 


e FM Radio (preferably with a knob-style tuning dial, but 
can be of any vintage) 


* Sandpaper, fine-grit (required for breadboard version, 
optional for soldered version) 


e Small screwdriver, Phillips or Pozi 

* Soldering iron & solder (soldered version only) 
e Tweezers OR needle nose pliers 

e Wire cutter/strippers 

e Standard pencil with eraser 


e Magnifying glass (optional, for seeing markings on small 
parts) 


4.4 Space Recommendations 


e Flat surface with enough room to lay out all components 
and tools 


e Adequate light 
e Comfortable seating 


e If soldering, good ventilation! At least an open window or 
an air filter (preferrably both) 


e Access to electricity 


5.0 
skills rundown 


5.1 Using Wire Cutters & Strippers 


Wire strippers are used to pull the insulating material off the 
outside of plastic-coated wires. 


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If you look at yours, you'll notice a cutting edge close to the 
hinge, notched places marked with wire sizes in the middle 
(these make holes when the cutters are closed), and a gripping 
surface at the end. 


To use, clip your wire piece a bit longer than needed, use 
the cutting edge to score the plastic insulation in the place 
where you would like to remove it, and then pull the wire 
through the appropriate-sized notch to slide the plastic sleeve 
off the end of the wire. 


32 


5.2 Breadboarding 


A breadboard is a quick-connect method for prototyping 
circuits. We will give a brief rundown here, but there are 
instructional videos and texts available online if you need 
further guidance. 


A breadboard allows for circuit prototyping and building 
without the need to solder the components together. Using a 
breadboard is a great way to test a circuit prior to soldering, or 
to build a circuit that you don't plan to keep. 


Breadboards are made of plastic with lots of little holes on 
one side and a layer of adhesive foam on the other, along with 
a hidden layer of conductive metal strips. The one pictured 
below is a standard orientation for breadboards. However, there 
are some different styles; double check the documentation for 
yours if it doesn't look like the one we have shown on the next 
page. 

Oriented with the top or work surface facing up, you can 
see the board is divided into three areas, each of which is a 
separate piece of plastic. The two smaller areas, referred to as 
"rails", have two columns of holes and are labeled with a red "+" 
symbol and a blue "-" symbol as well as a red line along one 
column of holes and a blue line along the other column of 
holes. The rails are generally used to supply power to the 
breadboard, so the red and blue markings indicate positive 


and negative power connections. 


The rails are located on either side of a larger central area 
with a distinct channel down the middle and a grid of holes that 


33 


is labeled with letters for the columns and numbers for the 
rows. The central piece doesn't have a consistent name, so we'll 


call it the terminal grid. 


The underside is usually covered by a foam adhesive pad 
which holds the plastic pieces together, secures the conductive 
metal strips inside the plastic, and insulates the metal strips 


top/work surface underside, insulator removed 


from whatever surface the board may be placed on. The board 
pictured above has had the foam pad removed so that the 
metal strips are visible. 


You can see on the picture of the underside that the rail 
pieces each have two long metal strips; these metal strips run 
beneath the columns of holes that are labeled with red or blue 
lines on the work surface. The terminal grid has two columns of 
horizontally oriented metal strips that run under the rows of 
holes on the work surface. 


34 


The metal strips have prongs that extend up into the holes 
on the front side of the board so that when a jumper wire or 
lead from an electrical component is pushed into the hole, it 
clips into the metal strip below and forms a reasonably secure 


connection, as shown below. 


Pushing a lead from one component and a lead from another 
component into holes in the same row connects those 
components electrically because they are both clipped in to 
the same piece of metal inside the board. 


The most common method for moving electricity around a 
breadboard is by using jumper wires like the one pictured here. 
For example, if you want to 
electrically connect multiple rows on 
the breadboard, you need to use a 
jumper wire. You can make your own 


out of solid-core wire with the ends 


stripped off, or you can purchase pre-made sets. 


35 


5.3 Soldering 


Solder is a metal alloy (a composite of multiple metals) that 
has a relatively low melting point. It is used as a sort of glue to 
bond together metal parts with a higher melting point. The 
solder and the parts being connected are heated together 
using a soldering iron, oven or torch; for our purpose you'll be 
using a soldering iron. The heat from the iron melts the solder 
which in turn fills the space between the parts. When the solder 
re-solidifies and the parts cool, the bond is fairly durable 
(though it can be broken or re-melted). The act of using solder 
in this way is referred to as soldering; any bond between 
pieces of metal created by soldering is referred to as a solder 
joint. When you are building electrical circuits, the solder joint 
allows electrical current to pass from one component to 
another. Soldering is also used for non-electrical purposes like 
plumbing and jewelry making. 


As soldering involves tools that can reach dangerously high 
temperatures, we strongly advise at least watching video-based 
tutorials or, ideally, getting in-person instruction. That said, we 
recognize that in-person instruction can be hard to come by 
and varies widely depending on where you live. Places to look 
for in-person instruction include but are not limited to: public 
libraries, maker or hacker spaces, ham radio clubs, and others. 


If in-person instruction is definitely not an option the 
electronics company Adafruit has a thorough guide to 
electronics soldering, including both written and video 
instructions, at learn.adafruit.com/adafruit-guide-excellent- 
soldering. 


36 


6.0 
initial preparations 


6.1 Making the coil 


(This is necessary for both breadboard and soldered 


assembly) 


Materials: Pencil, copper wire 


1. Cut a roughly 4"/10cm length of 24 


AWG/.5mm enamel-coated copper wire. 


2. Wind the wire around the eraser end 
of a pencil 4 times. The grooves in the 
metal part of the pencil can be used to 


hold the wire in place and provide basic 
spacing for the turns of the coil. 


3. Take the coil off the pencil to use. 
Because a pencil eraser is roughly 5mm 
in diameter, the coil is also roughly 5mm 


in diameter. 


4. Use fine-grit sandpaper to sand the 
legs of the coil up to where the turns 
begin, to remove the thin enamel coating 


© on the wire. 


37 


6.2 Preparing the copper board 


(Skip this if you're building on a breadboard!) 


1. Wearing eye protection, cut 
a 1 cm/.5" strip off one end of 
your copper board. You can 
do this with a coping saw, by 
scoring deeply with a craft 
knife and snapping the board 


using pliers, or with tin snips/ 
heavy-duty scissors. Heads up - the board is not easy to 
cut! Be patient and be careful to avoid cutting yourself. 


2. Take the strip and split it 
into 5 roughly even pieces, so 
you end up with six pieces 
that look something like this. 


3. Affix the smaller pieces to 
the larger one as shown here, 
using the heat-resistant 
adhesive of your choice (we 
used gorilla glue in the board 
shown here, but other options 
work just as well). 


38 


4. Create small solder pads on 
each of the smaller pieces of 
copper board by heating up the 
surface and applying solder 
until it forms a little pool. This 
will help to speed up soldering 


work later. 


5. Using the same method as 
the previous step, create small 
solder pads on the larger 
copper board in the locations 
shown in the image to the left. 


39 


7.0 
assembly instructions 


7.1 Breadboard Assembly 


1. Attach the 9-volt battery connector to 
the board. These connectors often have 
stranded core wires. Twist the ends as 
tightly as possible before pushing them 
into the breadboard to ensure a good 
connection. 

The wires will usually be insulated in 
black and red. Red indicates a "positive" 
lead and black indicates a "negative" 
lead. Push the black wire into a hole on 
the blue/negative rail on one end of the 
breadboard. Push the red wire into the a 


hole on the red/positive vertical rail 
immediately next to it. This configuration is not required, but it is 
a convention intended to help to keep track of the direction of 
current, in case you are working with more than one person or 


need to return to the board at a later time. 


2. On the opposite end of the board from 
where you attached the battery 
connector, connect the two negative rails 
with a jumper wire. Push one end of the 
wire into a hole on one blue vertical rail 


and the other end of the wire into a hole 


40 


on the blue vertical rail on the other side of the board. This 
means that both rails share the same part of the electrical 


current. 


] 3. The transistor we are using has 3 legs: 
| a Base, an Emitter, and a Collector. If you 
| look at the transistor in this circuit with 
the flat side facing towards you, it has 
the Base (B) in the center, the Collector 
(C) on the left and the Emitter (E) on the 
right.Place the transistor so each of the legs are in a separate 


row, and the C leg is close to the positive rail. Leave room for 
another component to go between the C and E legs. 


4. Place the 1uF ceramic capacitor (often 
+. | marked "100") between the C and E legs 
| of the transistor. Push each of the 

| capacitor's legs into holes in the same 
rows as the C and E legs of the 


transistor. 


5. Place the coil you prepared earlier so 
<: that one leg is in the same row as the C 
A leg of the transistor and the other is in a 
; separate row. The C leg of the transistor 
“| is now connected to the coil electrically, 


because both are touching the same 
piece of metal under the surface of the breadboard. 


4 


] 6. Use one of the 10nF ceramic 
capacitors (usually marked "103") to 
connect the coil end not connected to 
| the transistor to the negative rail. 


7. Use a jumper wire to connect the same 
row as in the previous step to the 
positive rail. 


8. Use the 22 kQ resistor to connect the 
row the same row as in the previous step 
to the row with the B leg of the transistor 
by inserting one leg of the capacitor in 
the same row as the B leg of the 


transistor and the other leg of the 
capacitor in the negative rail. (Note: this image shows the 
opposite angle from the previous image.) 


9. Use the other 10nF ceramic capacitor 
to connect the row with the B leg of the 
transistor to the negative rail, by inserting 
one leg of the capacitor in the same row 
| as the B leg of the transistor and the 


other leg of the capacitor in the negative 


rail. 
42 


10. Use the 10 kQ resistor to connect the 
row with the B leg of the transistor to the 
negative rail, by inserting one leg of the 
resistor in the same row as the B leg of 
the transistor and the other leg of the 


resistor in the negative rail. 


11. Carefully place the variable capacitor 
in the space between resistors, with one 
leg in the same row as the C leg of the 

transistor and the other leg in a row with 


no other components. 


12. Use a jumper wire to connect the row 
with only one leg of the variable 
capacitor in it to the negative rail by 
inserting one end of the jumper wire in 
the same row as the variable capacitor 
and the other end of the jumper wire in 


the negative rail. 


13. Use the 470 Q resistor to connect the 
E leg of the transistor to the negative rail, 
by inserting one leg of the resistor in the 
ise same row as the E leg of the transistor 
“| and the other leg of the resistor in the 


negative rail. (Note: this image shows the 


> 


opposite angle from the previous image.) 


43 


14. Insert the positive (longer) leg of the 
electrolytic capacitor in the same row as 
the B leg of the transistor. Insert the 
negative (shorter) leg in a row with no 


other components. 


15. The mono audio jack will likely have 
stranded wires like the battery 
connector. Twist the strands in the same 
j “| way. Insert the positive wire (usually 

À insulated with red plastic - if it isn't, it will 
be the only insulated wire) in the same 


row as the negative leg of the electrolytic capacitor. Insert the 
negative wire of the audio jack (generally bare copper, not 
insulated) in the negative rail. 


16. The antenna can be made of any type 
of wire, as long as it will fit in the holes in 
the breadboard. We've used a piece of 
stereo wire, but you could use a long 


jumper cable or other wire you have 
í available. As always, if the wire is 
stranded make sure to twist the strands tightly. Insert the 


antenna wire in the same row as the E leg of the transistor. 


44 


17. The circuit should be fully assembled! Attach a 9v battery, 
and skip to "Operating the Completed Radio Transmitter" for 


your next steps! 


45 


7.2 Soldered Assembly 


1.Begin with the copper-clad 
board you already prepared. You 
shouldn't need more solder than 
what is already pooled on the 
board. You will build the circuit by 
re-heating the solder and adding 


components to it. 

Going forward, the larger copper board is referred to as the 
"ground plate”, and it will be connected to the negative terminal 
of the battery. The smaller pieces of copper board affixed to 
the surface of the ground plate are referred to as "insulated 
pads"; they are the connection points for components that lead 
to the positive terminal of the battery. 


2. The transistor we are using has 
3 legs: a Base, an Emitter, and a 
Collector. If you look at the 
transistor in this circuit with the 
flat side facing towards you, it has 
the Base (B) in the center, the 
Collector (C) on the left and the 


Emitter (E) on the right. Orient the transistor so that it matches 
the image here, with the B lead to the left, the C lead to the top 
right, and the E lead to the bottom right. Affix the transistor to 
the insulated pads by touching the leads to the solder pads 
and re-heating the solder with the soldering iron until it melts. 


46 


3. Next, attach the 1uF ceramic 
capacitor (usually marked with 
"100") so it connects the C and E 
leads of the transistor. Use the 
same method as before of 
reheating each pool of solder 
while touching the component 


4. Using the same soldering 
method, affix one lead of the 470 
Q resistor to the same insulated 
pad as the E lead of the transistor. 
Connect the other lead of the 

470 Q resistor to the ground plate 
using the solder pad in the 


5. Use the wire strippers to 
remove a small amount of 

{| insulating plastic from one end of 
the antenna wire, exposing the 

| copper strands. Continuing to use 
the same method, solder the 


j exposed copper to the same 
insulated a as the E lead of the transistor and leads of the 


IF ceramic capacitor and 470 Q resistor. 


47 


6. With the same soldering 
method, affix one leg of the 
variable capacitor to the top right 
insulated pad that already 
connects to the C lead of the 


transistor and one lead of the 1uF 


ceramic capacitor. Connect the other leg of the variable 
capacitor to the ground plate using the solder pad in the top 
right corner of the board. 


7. Using the same soldering 

technique, attach one end of the 
coil to the top right insulated pad 
that also connects to one lead of 
the variable capacitor, the C lead 
of the transistor, and one lead of 


the 1uF ceramic capacitor. 
Connect the other end of the coil to the insulated pad at the 
center top of the board. 


8. Use the wire strippers to 
remove some insulation on the 
wires attached to the battery 
connector. Using the same 


soldering method, attach the 


| positive lead of the battery 
connector to the same center top insulated pad as the end of 
the coil. Affix the negative lead of the battery connector to the 
ground plate with the topmost solder pad. 

48 


9. With the same soldering 
technique, affix one lead of one of 
the 10nF ceramic capacitors 
(usually marked "103") to the same 
center top insulated pad as the 
positive lead of the battery 


connector. Affix the other lead of 
the 10nF ceramic capacitor to the ground plate using the 
solder pad just below where you attached the negative lead of 
the battery connector in the previous step. 


10. Solder one lead of the 22 kQ 
resistor to the same center top 
insulated pad as the coil, 10nF 
ceramic capacitor, and battery 


connector in the previous 3 


steps. Attach the other lead of 


the 22 kQ resistor to the same 


11. Use the same soldering 
technique to connect the positive 


lead (longer leg) of the 

YA electrolytic capacitor to same 
center insulated pad as the B 
lead of the transistor and one 
lead of the 22 kQ 

resistor. Connect the electrolytic capacitor's negative lead to 
the insulated pad to the left. 

49 


12. Use the wire strippers to 
expose the audio jack wires. 
Connect the positive wire of the 
audio jack (usually insulated with 
red plastic) to the same left 
insulated pad as the negative leg 
of the electrolytic capacitor. 


Connect the negative wire of the 


mn \| audio jack (either bare copper or 
insulated with black plastic) to the ground plate using the 
solder pad to the left of that insulated pad. 


13. Use the same soldering 
method to connect one lead of 
the 10 kQ resistor to the same 
center insulated pad as the 
“Hf | positive lead of the electrolytic 
\ \ capacitor, the B lead of the 
N \ | transistor, and the lead of the 22 


kQ resistor. Attach the other lead of that resistor to the ground 


plate using one of the solder pads below that insulated pad. 


14. Attach one lead of the 


remaining 10nF ceramic 


| capacitors to the same insulated 
S] | pad as in the previous step. 

AZ (Il | Attach the other lead of that 
à AU capacitor to the ground plate 

3 AY 


using the remaining solder pad. 


50 


15. The circuit should be fully assembled! Attach a 9v battery 
and continue on to "Operating the Completed Radio 


Transmitter" for your next steps! 


51 


7.3 Operating the Completed Radio Transmitter 


Once you've built your radio transmitter, operate it by following 
these steps: 


1. Connect a 9 volt battery to the battery connector and 
connect an audio source (such as a phone or computer) to the 


audio connector. 


2. Turn your audio source to the highest volume and play 
something you will recognize. 


3. You can find the audio you chose in step 2 in two ways: 


3.1. Turn on an FM radio receiver, and slowly scan through 
the stations until you find the audio. While this process of 
scanning works best with a radio that has a knob for tuning, 
a digitally-tuned radio will also work. With this method you 
leave the transmission frequency of your radio transmitter 
as-is and you adjust the reception frequency of the receiver. 


3.2. Set your radio receiver to an empty channel at the low 
end of the FM spectrum (871-90.9, generally) and use a 
small screwdriver to carefully turn the screw head inside the 
variable capacitor on your transmitter. With this method you 
adjust the transmission frequency of your radio transmitter. 


4. Once you've found your audio, play around with both 
methods to find the best sound! You can experiment with how 
far apart the transmitter and receiver can be, what causes 


interference, what increases your signal strength, etc. 
52 


7.4 Troubleshooting 


1. If you are having trouble picking up your radio frequency, or it 
seems to not be working, try the following things: 


2. Go through the steps of your assembly method and double- 
check that each component is connected in the correct place 


and orientation. 


3. If you assembled your circuit on a breadboard, lightly sand 
the leads on each component. There may be transparent 
insulation on the leads that is preventing electricity from 
moving through the circuit. 


4. If you assembled your circuit by soldering, carefully reheat 
each of the solder joints to make sure that solder has 
connected each of the components. 


5. Make sure that all batteries have a full charge. 


6. Check that your radio is receiving other frequencies by 


scanning for local radio stations. 


53 


8.0 
acknowledgements 


This text is an expansion of work done by Tetsuo Kogawa. 
The instructions expand on his Simplest FM Transmitter 
(anarchytranslocal.jp/radio/micro/howtosimplestTX.html) and 


the circuit diagram is based on a layout for the BC337 
transistor-based circuit (translocal.jp/radio/micro/ 
simplestTX_layout_for__BC337.pdf). 


We would also like to thank Alex Custodio, Michael lantorno, 
Darren Wershler, Lee Wilkins, and members of the May 2023 
graduate class on maintenance, repair, and sustainability at 
Concordia University (Montreal, Canada) for all they did to 


inspire us to produce this text. 


Finally, this pamphlet would not have been possible without 
the infrastructure of the Media Archaeology Lab (MAL) and the 
resources that go into supporting the lab; as such, we would 
like to thank the University of Colorado Boulder’s College of 
Media, Communication, and Information, the College of Arts & 
Sciences, the Media Studies Department, and the English 
Department for their continued support; we would also like to 
thank Brad Feld, Vint Cerf, and Google for their ongoing, 
generous support of the lab as well. Long live the MAL! 


54 


9.0 
bios 


libi striegl is Managing Director of the Media Archaeology 
Lab. She is an artist and researcher interested in collaborative 
engagement, performative chaos, archival impermanence and 
DIY/DIT defamiliarization. Her work includes the workshop series 
Voluntary Deconvenience, the DinaCon installation SolFM, and 
the satirical techno-collaborative Sharing Turtle. 


Lori Emerson is Associate Professor of Media Studies and 
Director of the Intermedia Arts, Writing, and Performance 
Program at the University of Colorado Boulder. She is also 
Director of the Media Archaeology Lab. Emerson is author of 
the forthcoming Other Networks (Anthology Editions, 2024), co- 
author of THE LAB BOOK: Situated Practices in Media Studies 
(University of Minnesota Press, 2021), author of Reading Writing 
Interfaces: From the Digital to the Bookbound (University of 
Minnesota Press June, 2014), and editor of numerous 


collections. 


55 


emell\/|/\|_ 


www.othernetworks.net