I have built a Morse code straight key using brass plates, small bearings, brass shaft, and some brass screws from power supply binding posts. The key is mounted on the same aluminum plate with my home-brewed electronic keyer with paddles and desk microphone. With this customized straight key, I hope to get a better sense of rythm in sending Morse code.
To watch the straight key in action, along with the electronic keyer with paddles, click here.
I was testing my Morse Code transmitter last night by sending a CQ on 7.102 MHz using various transmit powers ranging from 5 to 10 watts QRP, up to 100 watts full power, using an ICOM 718 and a home-brewed antenna. It appears that 4 stations (one in the Pacific and 3 on the other side of the world—in the US) heard my signal, as reported in the Reverse Beacon Network (an automated system that receives and logs Morse code transmissions).
While this is probably the farthest distance to date that my signal was able to reach, this is just one-way communication. Probably as I improve my antenna, I’d also be able to hear the faint signals coming from the other side of the world.
I’ve built a simple HF (40-meter band) wire antenna with some scrap wires, a length of RG8 cable, PVC pipe as insulator, and some way of securing and making it waterproof. This antenna is intended for receiving (RX only) so I could listen to local voice and Morse code net calls using a Software-Defined Radio (SDR).
The antenna is a dipole with 10 meters of conductor on each side. One conductor is soldered directly to the coax’s outer conductor (braid), while the other conductor is soldered to the coax’s center conductor. I did not use a balun for this antenna, but you may try to use one. Each end of the conductors terminate with a PVC insulator. If you plan on transmiting with a wire antenna, you will need to adjust the length of each conductor for best SWR. I will be using this antenna with an HF radio to send and receive signals in the 40-meter band (7.000 to 7.200 MHz).
I have built an ultra-compact DIY iambic Morse code keyer for a dual-paddle key based on the work of PA3HCM. The keyer uses an Arduino Uno and a few components such as a potentiometer for adjusting the words per minute (WPM), a small speaker, some resistors, and LED indicators. I housed the circuitry in a neat enclosure and added some terminals (for signal line-out and an auxiliary connection for a second key). I then attached a dual-paddle key onto the enclosure, making the keyer and key setup a very portable trainer for code practice.
I’ve recently finished building a satellite traker based on SATNOGS satellite tracker.
The automated tracker uses an Arduino to control a pair of stepper motors that move two cross-yagi antennas (VHF and UHF). The Arduino receives satellite’s azimuth and elevation info using the tracking software Gpredict. Hamlib is then used to establish a link between the computer and Arduino through USB connection via EasyComm III protocol.
The tracker was built with parts taken from a drill such as gears and bearings, along with a pair of worm drive from a photocopying machine. The total costs of the project is less than 100 USD, antennas included. The tracker uses two A4988 stepper motor driver, and two geared stepper motors. A weatherproof metal ammo box is used as a case, and rubber seals (particularly in the azimuth and elevation shafts) prevent water from entering.
Initial tests showed good tracking accuracy, allowing reliable full-duplex communications with any passing amateur radio or weather satellite.
I have finished building and testing a DIY Terminal Node Controller (TNC). With DIY TNC, it is possible for any radio to encode and decode signals in the Automatic Packet Reporting System (APRS) format. This TNC is based on the home-brewed TNC project by VK3DAN.
The TNC requires a smart phone running APRSdroid connected via bluetooth. It taps directly to a radio through dedicated audio line-in and line-out ports (or microphone in and speaker out). The PTT is automatically activated as a packet is transmitted. I’ve tested this TNC to work with the International Space Station’s (ISS) digipeater at 145.825 MHz, digipath: ARISS.
PSAT2 transmits SSTV images at 435.360 MHz (UHF) which may be received using just a DIY Moxon-Yagi satellite antenna, a UHF radio, and a decoder such as Robot 36 running on a smartphone (Android).
Here are some images decoded on May 1 and May 5, 2020, as PSAT2 passes over the Philippines.
SSTV transmission in PSAT2 is only active in daytime. Doppler effect compensation is necessary to properly receive the transmission. Tune your radio from 435.370 MHz down to 435.350 MHz from start to end of the pass. You may decode up to two SSTV images per pass.