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The Adonis Electric Co., Ltd. catalog details a range of amateur radio microphones, including mobile, desktop, and bike-specific models, alongside essential accessories. Featured products include the _FX-6_ flexible microphone and various interconnecting cables designed for seamless integration with transceivers from Icom, Yaesu, and Kenwood. The catalog also presents specialized items like microphone selectors, alternator noise filters, and peripherals such as voice memory units and double VOX controllers, enhancing operational flexibility for hams. These products are engineered to improve audio clarity and operational convenience for amateur radio operators, particularly in mobile and fixed station environments. The inclusion of conversion codes ensures compatibility across major transceiver brands, simplifying setup. The alternator noise filter addresses common mobile RFI issues, contributing to cleaner signal reception and transmission, which is crucial for effective DXing and contesting.

Mitigating RF noise in a mobile operating environment, particularly within a _Jeep TJ_ vehicle, presents unique challenges due to the vehicle's electrical system and chassis characteristics. This resource details practical methods for identifying and suppressing various forms of radio frequency interference (RFI) that can degrade receiver performance for both CB and amateur radio transceivers. It covers common noise sources such as ignition systems, alternators, fuel pumps, and computer modules, explaining how these components generate broadband or specific frequency noise that impacts radio communications. The guide offers actionable solutions, including proper grounding techniques, the strategic use of ferrite beads and toroids on power and data lines, and the installation of bypass capacitors. It discusses the effectiveness of different filtering strategies for DC power lines and antenna feedlines, illustrating how a clean power supply and shielded cabling can significantly reduce conducted and radiated noise. The information presented helps operators achieve a lower noise floor, improving signal-to-noise ratio and enabling clearer reception of weak signals, which is crucial for effective mobile DXing or local ragchewing.

Mobile RFI, often manifesting as persistent noise in the receiver even with the antenna disconnected, frequently originates from the vehicle's power supply system. This guide details systematic troubleshooting steps, beginning with isolating the radio from the car's 12-volt supply to confirm the power system as the noise source. It emphasizes the critical importance of drawing power directly from the battery using **heavy gauge wire**, bypassing the fuse block to leverage the battery's natural capacitance for RFI suppression and ensuring a solid RF ground. Proper routing of power lines through the firewall is also covered, advocating for dedicated grommeted holes to prevent inductive coupling from other wiring harnesses. The article stresses the necessity of fusing both positive and negative leads from the battery, a crucial safety measure to prevent damage to the rig and mitigate high-current risks should the battery's engine block ground become compromised during service. Addressing **alternator whine**, a common high-pitched noise that varies with engine speed, the resource suggests checking battery connections and the alternator-to-battery harness for looseness or corrosion. It also mentions the utility of adding an external RF noise suppression capacitor in parallel with the alternator's internal capacitor for enhanced filtering, and the effectiveness of commercially available in-line power supply filters.

How to create a low pass filter able to reduce or even remove the noise generated from your car or truck alternator

How to build a low-pass filter to remove alternator whine from your car

On December 12, 1901, Guglielmo Marconi successfully received the first transatlantic wireless communication, a Morse code "S" (three dots), at 04:30 GMT. This article details the setup for this groundbreaking experiment, noting Marconi's receiver in St. John’s, Newfoundland, Canada, utilized a _coherer_ and an antenna elevated by balloons and kites. The transmitting station at Poldhu, Cornwall, England, featured twenty-four 200-foot ships' masts and a 25-kilowatt alternator. The resource explains how this contact disproved contemporary beliefs about radio wave limitations due to Earth's curvature, later understood through _ionospheric propagation_. It frames Marconi's achievement as the "very first DX" in amateur radio terms, defining DX as telegraphic shorthand for distance and _DXing_ as the hobby of receiving distant signals. The article also provides external links for further reading on Marconi's experiments and the science behind transatlantic radio signal reception.

Early 20th-century transatlantic wireless communication efforts involved distinct technical approaches by Reginald Fessenden and Guglielmo Marconi. Marconi's systems, operational until approximately 1912, primarily utilized _spark technology_ for wireless telegraphy, facilitating Morse code communication between ships and across oceans. His Poldhu station in December 1901 radiated signals in the MF band around 850 kHz, later evolving to 272 kHz in October 1902, and eventually 45 kHz by late 1907 with increasingly larger antenna structures like the pyramidal monopole and capacitive top-loaded arrays. Fessenden, conversely, focused on _continuous wave transmission_ for wireless telephony, recognizing its necessity for speech. His transatlantic experiments in 1906 employed synchronous rotary-spark-gap transmitters and 420-foot umbrella top-loaded antennas at Brant Rock, MA, and Machrihanish, Scotland, tuned to approximately 80 kHz. Fessenden later utilized the _Alexanderson HF alternator_ at 75 kHz by late 1906 for pure CW transmission, integrating a carbon microphone for amplitude modulation. Receiver technology also differed, with Marconi initially relying on untuned coherer-type detectors, later developing the magnetic detector in 1902, while Fessenden's CW approach necessitated more advanced detection methods.