Recommend a good RF projet ? - Page 1
Forum section: electronics / beginners

author: lordvader88
author_rank: Frequent Contributor
timestamp: July 18, 2019, 06:32:19 am
content: I just got some more RF JFETs, so I have 4 types of them, and various RF BJT typesWhat's something cool I could make, I barely made anything RF, but now i have the most common parts, and varactors too

author: OwO
author_rank: Super Contributor
timestamp: July 18, 2019, 09:41:51 am
content: FM transmitter.

author: lordvader88
author_rank: Frequent Contributor
timestamp: July 18, 2019, 09:12:05 pm
content: 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.

author: Electro Fan
author_rank: Super Contributor
timestamp: July 19, 2019, 03:46:12 am
content: https://youtu.be/MMgzUGBfXiE

author: lordvader88
author_rank: Frequent Contributor
timestamp: July 19, 2019, 02:59:04 pm
content: Quote from: Electro Fan on July 19, 2019, 03:46:12 amAh 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.

author: David Hess
author_rank: Super Contributor
timestamp: July 19, 2019, 03:25:48 pm
content: 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.

author: Donald05
author_rank: Newbie
timestamp: July 22, 2019, 05:55:27 am
content: 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/

author: vk6zgo
author_rank: Super Contributor
timestamp: July 22, 2019, 07:17:36 am
content: 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!

author: ogden
author_rank: Super Contributor
timestamp: July 22, 2019, 07:34:56 am
content: 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.

author: bd139
author_rank: Super Contributor
timestamp: July 22, 2019, 08:12:04 am
content: Totally agree.Get an amateur radio license first. That'll give you some understanding hoops to jump through.

author: ogden
author_rank: Super Contributor
timestamp: July 22, 2019, 08:23:52 am
content: Quote from: bd139 on July 22, 2019, 08:12:04 amRight. Other way around: there are loads of interesting RF projects that does not transmit but receive instead.

author: bd139
author_rank: Super Contributor
timestamp: July 22, 2019, 08:32:52 am
content: 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.pdfHere'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

author: Nitrousoxide
author_rank: Regular Contributor
timestamp: July 23, 2019, 01:07:33 pm
content: A superheterodyne receiver would be a good challenge! It involves amplifier, mixer and filter design.

author: lordvader88
author_rank: Frequent Contributor
timestamp: July 23, 2019, 05:40:59 pm
content: 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.