PSK31 is designed as a mode for keyboard-to-keyboard conversation with a data rate close to typing speed. The first digital mode we will start with is PSK31. We start with insuring participants have the hardware configured correctly and on the same frequency (443.100 MHz), provide a quick overview of the Fldigi software, have all participants configured for the same digital mode, then send a test transmission from one station and insure all participants receive it. Since we will be using VOX to trigger transmitting there is nothing to configure in the Transceiver control dialogue window so you can click next. For the Audio Devices dialogue page insure PortAudio is checked and the USB audio device is selected. Once the package is installed, the first time you run Fldigi you will be walked through the installation wizard. Linux users should install Fldigi from your Linux distribution repository. Windows and OSX coverusers can go ahead and download Fldigi from the website and run the file. Fldigi allows your soundcard to be used as a AFSK modem. Softwareįldigi is a popular digital mode software package we will be using that is available on Windows, Linux, and OSX. For now set the frequency for 433.100 MHz knowing some exercises will require changing frequencies. When turning the radio on a low volume level is all that is required. The table below provides menu settings required. The appropriate menu settings for VOX and SQL need to be programmed into the HT as well as a few other settings. Because the HT will transmit when hearing ANY audio the squelch (SQL) needs to be set to block noise and permit covervalid signals received. Instead the handheld is configured to use a feature called VOX which has the HT transmit when it hears ANY audio on the microphone pin from the cable. The Baofeng audio cable is just that, it only connects audio between radio and an audio device and is not used to key the handheld to transmit audio. Optional Baofeng Programming Cable Programming the Radio USB sound dongles that use 3.5MM TRRS connections ($8 USD) are easily found on Amazon. The isolation also adds a layer of physical protection from damaging your laptop. Isolating the digital mode audio from laptop system audio prevents inadvertently have operating system notification sounds being sent out to the radio. Rather than buy an adapter that converts the 3.5MM TRRS male connector to line-in/line-out 3.5MM stereo male connections and connect to the sound card built-in to the laptop, I opted to include a layer of audio isolation and add a USB sound dongle that accepts a 3.5MM TRRS male connection. The Baofeng Audio cable has a K2 connector to the radio on the one end and a 3.5MM TRRS Male connector on the other end. Baofeng offers an audio interface cable ($19 USD) intended for digital mode use making it cheap and easy for RF to/from audio connectivity. The Baofeng UV-5R ($26 USD) is probably the most recognizable VHF/UHF handheld (HT) by hams and radio enthusiasts alike. The lab exercises will have participants communicating with other participants stations. Participants should have purchased all hardware in advance of the workshop. We will then install and familiarize ourselves with open source software packages used for encoding/decoding digital modes. We start with building participants build their VHF/UHF Amateur Radio stations. see relationships between data rates and bandwidth.learn each modes strengths and weaknesses.develop familiarity with each mode starting with what each mode sounds like.Experimenting with HF digital modes in a workshop setting on VHF/UHF provides ideal conditions for participants to: Truth be told, most Amateur Radio digital modes these days are developed for and used on HF to address resilience to band conditions. The station and a laptop running a currently supported operating system would be the only pre-requisites. I agreed to package a workshop that included using a simple low cost portable VHF/UHF digital mode station from readily available kit for under $75 USD. So we discussed revisiting a digital mode project I worked on a year ago and packaging it as a workshop that gives new Hams a taste of digital modes and inspires them to be active with it. When demoing Amateur Radio at past HOPE conferences, running digital modes has always had a big draw of interest but shy away from talking into a microphone. While we see many getting their Technician class licenses and even upgrading, we are not seeing many put their new licenses to use. A friend of mine and I were chatting a few months ago about maker and hacker communities taking interest in Amateur Radio.
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