Building a FM transmitter and receiver.

[Chiranka K]

Hey guys,
I want to build my own FM transmitter and receivers. However, most of the stuff I saw online was simple stuff. I have knowledge about basic circuit design and communication systems.
1. I want to build one that is good.
2. I want to introduce an impedance-matching circuit to the transmitter side. (so the transmitter circuit has to be a good one )
3. Where can I start learning stuff related to this design?

 

[BigBoss]

Learning Steps.
-Designing an efficient and low noise oscillator
-Designing driver stage
-Designing Power Stage

Start with Power Stage and test it under appropriate conditions. If it woks well, go ahead to previous step.

 

[BradtheRad]

Running an FM receiver is one thing. As for transmitting, municipal regulations severely limit your activity. From an electronics mail-order house I purchased a $10 kit which transmits a weak signal to a nearby radio on the normal commercial FM band. The tuner is one section, followed by the demodulator. For experimenters there are various receiver projects to pick up civil service bands such as police band, aircraft band, etc. These operate at a frequency range which presents challenges of its own. You may find a local club of radio enthusiasts who can provide assistance. Or, many radio enthusiasts run their own website containing electronics articles and projects.

 

[danadakk]

Lots of info here, look at Dec issues for summary for the year of articles :

QST Magazine: Amateur Radio Magazine

"QST", in amateur radio shorthand, means "Calling all Stations" It's also the name of the magazine of the American Radio Relay League, the dominant and influential association of hams in the US. The magazine was first published in December 1915

www.worldradiohistory.com

https://www.worldradiohistory.com/BOOKSHELF-ARH/Bookshelf_ARRL.htm Each handbook has a transmitter
design/project section.


Regards, Dana.

 

[Chiranka K]

Running an FM receiver is one thing. As for transmitting, municipal regulations severely limit your activity. From an electronics mail-order house I purchased a $10 kit which transmits a weak signal to a nearby radio on the normal commercial FM band. The tuner is one section, followed by the demodulator. For experimenters there are various receiver projects to pick up civil service bands such as police band, aircraft band, etc. These operate at a frequency range which presents challenges of its own. You may find a local club of radio enthusiasts who can provide assistance. Or, many radio enthusiasts run their own website containing electronics articles and projects.

Could you send me links of such websites where i can find stuff. I want to build a good project. Most of the one's i see are basic transmitters and recievers

--- Updated Aug 14, 2024 ---

Learning Steps.
-Designing an efficient and low noise oscillator
-Designing driver stage
-Designing Power Stage

Start with Power Stage and test it under appropriate conditions. If it woks well, go ahead to previous step.

Any material for this?

 

[BradtheRad]

N5DUX Ham Radio PDF Archive

Ham radio PDF repository curated by N5DUX. All amateur radio-related projects, tips, tricks, and tools

www.n5dux.com

WorldRadioHistory: Radio Music Electronics Publications ALL FREE

WorldRadioHistory: Thousands of Radio Music Electronics Publications ALL FREE

www.worldradiohistory.com

 

[KlausST]

Hi,

I miss a lot of information here. Like:
* what it is used for.
* what is the information transported via the FM? Is it analog, maybe audio (voice, music, single or multiple channels)...
* is it digital (data rate, coding ...)
* what RF (carrier) frequency range
* needed (modulation) bandwidth
* RF power (or expected distance ...)
* you want to build with discretes, ICs, modules, ready to buy ...
* what does "good" mean? Good in the meaning of low power consumption, best availability, low maintenance, low cost, waterproof, rugged metal case... I expect a specification with numbers and units.

I mean an "FM transmitter / reciever" could be anything from a handheld garage door opener to a 100kW professional audio broadcast station.
From $1 to $100k or more...

Klaus

 

[Chiranka K]

Hi,

I miss a lot of information here. Like:
* what it is used for.
* what is the information transported via the FM? Is it analog, maybe audio (voice, music, single or multiple channels)...
* is it digital (data rate, coding ...)
* what RF (carrier) frequency range
* needed (modulation) bandwidth
* RF power (or expected distance ...)
* you want to build with discretes, ICs, modules, ready to buy ...
* what does "good" mean? Good in the meaning of low power consumption, best availability, low maintenance, low cost, waterproof, rugged metal case... I expect a specification with numbers and units.

I mean an "FM transmitter / reciever" could be anything from a handheld garage door opener to a 100kW professional audio broadcast station.
From $1 to $100k or more...

Klaus

Sorry for the missed information.
Its a 4 month mini project that im doing as a part of my degree.
the information will be audio.
The frequency range i was thinking of something around the 80-90
I dont really need high power, low power is good enough for in-room demonstration
By good i mean, it should be of the level of a engineer, and not a high school project.

 

[KlausST]

it should be of the level of a engineer

sorry if I have to repeat: But an engineer does electronics specifications with numbers and units
... and design using physics and math.

I can´t type in "low power" into my calculator.

I do understand that you don´t expect calculations from us .. instead links to documents.
I can´t help with hte documents.
But I can recommend just to do internet search. Then you can filter out "the direction" ... of what you are after
Please focus on "professional information", that is manly from semiconductor manufacturers, FM designers, universities and so on.
You can also recognize good informatins when they provide tables of sepcifications, technical descriptions, design recommendations, schematics, PCB layout.

Please don´t rely on crappy hobbyists informations. (for sure there are good hobbyists)

This all should help to find numbers you can work with later ... for your design.

Btw: I wonder why you are looking for a receiver. Any FM radio receiver will, do .. I expect you to already have one laying around.

Klaus

 

[BradtheRad]

One obvious option that comes to mind is the frequency readout. Is it analog or is it digital? The analog method traditionally involves a mechanical contrivance attached to the tuner. You would need to pencil in the frequencies, or print a list custom-sized to fit your homemade radio.

* Digital readout has a frequency counter capable of 80-110 MHz. Optional are prescalers dividing by 10,000 or 100,000 (which allows your counter to have 4 or 5 digits). In many ways a digital counter is easier to build than the analog type. And a digital readout is a chief method to give your project an advanced modern look.

Notice that the frequency counter can also be hooked up to a transmitter to tell you it's 'on the air' and at what frequency.

 

[Chiranka K]

sorry if I have to repeat: But an engineer does electronics specifications with numbers and units
... and design using physics and math.

I can´t type in "low power" into my calculator.

I do understand that you don´t expect calculations from us .. instead links to documents.
I can´t help with hte documents.
But I can recommend just to do internet search. Then you can filter out "the direction" ... of what you are after
Please focus on "professional information", that is manly from semiconductor manufacturers, FM designers, universities and so on.
You can also recognize good informatins when they provide tables of sepcifications, technical descriptions, design recommendations, schematics, PCB layout.

Please don´t rely on crappy hobbyists informations. (for sure there are good hobbyists)

This all should help to find numbers you can work with later ... for your design.

Btw: I wonder why you are looking for a receiver. Any FM radio receiver will, do .. I expect you to already have one laying around.

Klaus

Thank you, I'll try and search on the Internet.
I am doing this as a mini-project of a 4 month duration for my course; it seemed like a fun project to do in analog design. However, if u have any other suggestions on projects I can do, which include analog electronics along with maybe signal processing too, which will take about 4-5 months to finish and have a good amount of learning outcomes, I'm open to your suggestions.

Thank you.

--- Updated Aug 15, 2024 ---

One obvious option that comes to mind is the frequency readout. Is it analog or is it digital? The analog method traditionally involves a mechanical contrivance attached to the tuner. You would need to pencil in the frequencies, or print a list custom-sized to fit your homemade radio.

* Digital readout has a frequency counter capable of 80-110 MHz. Optional are prescalers dividing by 10,000 or 100,000 (which allows your counter to have 4 or 5 digits). In many ways a digital counter is easier to build than the analog type. And a digital readout is a chief method to give your project an advanced modern look.

Notice that the frequency counter can also be hooked up to a transmitter to tell you it's 'on the air' and at what frequency.

Im really new to this, so i dont really have a idea of what i want. But i'll look in the digital readout method too. Any materials where i can look into this?
Thank you.

 

[BradtheRad]

A forum search here will turn up a few discussions about counters. Example, Forrest Mims published a 6-digit project based on two 15543 IC's (15443?).

See:
www.edaboard.com/threads/correct-connection-of-bjts-in-counter.380204/