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Posts Tagged ‘ham radio’

13.8V 5A power supply

Thursday, February 28th, 2019

Dilshan Jayakody published a new build: 13.8V power supplies are commonly used in armature radio experiments. Most of the portable armature radio transceivers are designed to work with a 13.8V power source. We mainly build this power supply unit to power some of our armature radio circuits and modules. This...

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Posted in power supply | 1 Comment »

Automated channel switching with Motorola GM3x0

Tuesday, October 16th, 2018

Florian Wolters wrote an article on automated channel switching for POCSAG/DAPNET transmissions on MMDVM system: With the integration of POCSAG/DAPNET features into the MMDVM/MMDVMHost I came to think about if it would be possible to combine an MMDVM repeater/HotSpot with a DAPNET tranmitter. The advantage in Germany is that there...

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SI5351 VFO project

Tuesday, May 22nd, 2018

Dave Richards (a.k.a. AA7EE) has a nice write-up about building another Si5351 VFO project: To many, this will be just another Si5351 VFO project, with nothing to distinguish it from the others. In fact, that’s exactly what it is. The “how to” of connecting an Arduino board to an Si5351...

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RX/TX sequencer

Wednesday, May 17th, 2017

Lukas Fässler has designed and built an RX/TX sequencer based on a PIC16F18325,  that is available on github: Much like the beacon keyer presented here earlier, this RX/TX sequencer is a simple but useful little device. Its typical use is in ham radio applications when a separate power amplifier (PA) and/or a...

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Posted in digital radio data, PIC | No Comments »

Beacon Keyer

Thursday, April 27th, 2017

Lukas Fässler from Soldernerd published a project writeup showing how he built a PIC-based beacon keyer: This is likely the first ham radio related project that I document here on this blog But my very first PIC project was a beacon keyer that I made for my father, HB9BBD. That...

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Posted in DIY, PIC | 1 Comment »

Homebrew 40dB step attenuator

Wednesday, December 28th, 2016

flathagen blogged about his step attenuator build: A home lab needs a step attenuator. It helps in evaluating RF amplifiers, filters and receivers. Both the legendary EMRFD-book, the ARRL handbook, and a variety of QST-articles provides circuit examples for building a homebrew device. Most of them follow the design principles...

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Homebrew dummy load

Saturday, August 27th, 2016

A simple DIY dummy load project from Flathagen: I have created a simple 50 Ω dummy load to test transmitters. I also added a simple RF diode detector so I can measure the peak voltage, and calculate the power. The dummy load consists of eight 100 Ω resistors rated at...

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EMRFD Direct conversion 40m receiver in a tea caddy

Thursday, May 5th, 2016

Flathagen has made a DIY EMRFD Direct conversion 40m receiver in a tea caddy: I woke up one day eager to build something simple (at least I thought is was simple) and opened up the first chapter in EMRFD and decided to build the 40m direct conversion receiver. I already had...

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Embedded Linux APRS iGate tutorial

Wednesday, August 5th, 2015

A detailed tutorial on how to make your own APRS iGate (Automatic Packet Reporting System)  from Andrew Milluzzi: With the super cheap embedded Linux platforms (Raspi, Beaglebone, etc.) and cheap TV dongles, it is really easy to make your own APRS iGate, just like the one in the photo above....

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Audible Morse code to text message converter

Monday, April 21st, 2014

Dilshan Jayakody writes: Morse View is an open source software project to convert audible Morse codes to text messages. This application is capable to convert Morse codes from wave files or from the audio line/microphone inputs. Conversion from Morse code to text can perform based on amplitude and frequency decomposition...

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Amateur radio study guide has much information about electronics

Tuesday, June 21st, 2011

Ham radio is nothing new, however if your new to electronics, or interested  in becoming a ham, we suggest reading one of Dan's self-study guides. The RMS value of an AC signal is the voltage that causes the same power dissipation as a DC voltage of the same value. (G5B07)...

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