Recommend a good RF projet ?

[lordvader88]

I just got some more RF JFETs, so I have 4 types of them, and various RF BJT types

What's something cool I could make, I barely made anything RF, but now i have the most common parts, and varactors too

[OwO]

FM transmitter.

[lordvader88]

You know I don't yet understand how FM is created by the circuits, I can sort of figure out what AM circuits are doing, but the actual FM part, I don't see it yet.

I just got a bunch of new breadboards I should make a weak transmitter and receiver.

[Electro Fan]

https://youtu.be/MMgzUGBfXiE

[lordvader88]

https://youtu.be/MMgzUGBfXiE

Ah that reminds me I forgot to order super glue for deadbug copper clad projets. I have about 50 Copperclad boards, and never used 1 yet.

[David Hess]

A low input capacitance active probe for your oscilloscope would be handy and useful even down to 100 MHz.  They require both RF JFETs and RF bipolar transistors.

[Donald05]

There are lot of possible answers for your question. What level of complexity should the project be? Anyway here is a couple of good RF projects you can give a try.
Remote powered Plant watering system - https://www.gadgetronicx.com/solar-powered-remote-operated-plant-watering/
Simple RF Transmitter and Receiver - https://www.instructables.com/id/RF-Transmitter-and-Receiver/

[vk6zgo]

The FM transmitter will teach you two things:-
(1) Why self excited oscillators are not used at VHF by other than rank noobs!
(2) Why breadboards are not used at VHF by other than rank noobs!

[ogden]

I am not sure that transmitter is good idea for "RF noob". Right next to FM are Air Traffic Control and other "sensitive" frequency bands.

[bd139]

Totally agree.

Get an amateur radio license first. That'll give you some understanding hoops to jump through.

[ogden]

Get an amateur radio license first.

Right. Other way around: there are loads of interesting RF projects that does not transmit but receive instead.

[bd139]

Good point.

Get a license before you build a transmitter though. It gives you some allocated space to play in when you screw up where you'll cause little damage. Even the ISM bands have heavy power and antenna restrictions which you need to understand before wandering in with a nuke.

Good RX project. Read it and build the first project: http://www.arrl.org/files/file/Product%20Notes/chapter_1.pdf

Here's the one I built to get an idea what results to expect:




.....

If you have discrete parts you can build a direct conversion receiver as well. Typical example: http://www.phonestack.com/farhan/dc40.html

[Nitrousoxide]

A superheterodyne receiver would be a good challenge! It involves amplifier, mixer and filter design.

[lordvader88]

Ok some good ideas here. I'm going to make a 2 BJT transismitter, and use the hybrid pi-model and see if I'm anywhere near right. Lot's of basic circuits I should do it for because I know I'll get stuck.