rating

324 links - and 17 categories

Chokes and Isolation Transformers for Receiving Antennas - Chokes and isolation transformers are essential for receiving antennas to mitigate common mode current, which induces noise and interferes with signal quality. Common mode chokes, formed by winding feedline through ferrite cores, block unwanted current effectively. Proper selection of core material and winding turns ensures resonance near the operating frequency, reducing interference. Isolation transformers further minimize interference, crucial for multi-transmitter stations.
[ Hits: 60 | Votes: 1 | Rating: 9 ]

Repairing a dead Kenwood TS-850S - The author fixed a friend's Kenwood TS-850S radio, which suffered from Capacitor Plague, a common problem in 1990s electronics where capacitors leak and damage circuit boards. The CAR board, responsible for generating signals, was especially affected. The author cleaned the board, replaced the capacitors, and repaired a broken trace. Although the radio mostly functioned afterward, the "Slope Tune" control behaved abnormally. The cause seems to be a software issue, not a hardware one.
[ Hits: 32 | Votes: 0 | Rating: 0 ]

Prevention and Suppression of RF Interference to Audio Systems - In this study, the author builds upon Muncy's research, demonstrating that radio-frequency current on cable shields affects audio systems through the "pin 1 problem" and shield-current-induced noise (SCIN). An enhanced equivalent circuit for ferrite chokes is proposed, addressing dimensional resonance and inductor self-resonance. Field tests confirm that chokes reduce interference across 500 kHz to 1,000 MHz. Guidelines for diagnosing and mitigating EMI from various sources are provided for product development and field installations.
[ Hits: 47 | Votes: 0 | Rating: 0 ]

ARJAN-5 5 band SDR - This project enhances Arjan te Marvelde's uSDR-pico by integrating a waterfall display feature. By adding an ILI9341 240x320 2.4" TFT display and modifying the software, the goal is to provide a panadapter to the existing transceiver. Initially developed with Visual Studio, the code was later migrated to Arduino IDE for Raspberry Pi Pico compatibility. The focus remains on preserving the original software, primarily enhancing the dsp.c file for waterfall implementation.
[ Hits: 53 | Votes: 0 | Rating: 0 ]