Search results
Query: LF
Links: 608 | Categories: 7
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Here is a simple, self-contained beacon which can run a few milliwatts or as much as a watt depending on choice of amplifier and supply voltage.
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Call Book Log 3.0 is a web-based logging solution for amateur radio operators, designed for self-hosting on a web server with MySQL/MariaDB and PHP 7+ support. It provides a mobile-friendly interface for viewing, adding, editing, deleting, backing up, and restoring QSO logs. The software features a streamlined setup process, allowing users to quickly deploy a personal logging system accessible via any web browser. Key functionalities include displaying the last **5** contact dates for previously worked stations, enhancing log management by providing immediate historical context during QSO entry. The system also includes a central administrative section for authenticated users to manage log entries. The 3.0 version represents a significant code overhaul, focusing on improved performance and a more *visually appealing* user experience compared to earlier iterations. Enhancements include better pagination, a redesigned menu with icons, and color-changing rows for improved readability. The add log page now incorporates a one-click time update feature, addressing user feedback regarding time synchronization during rapid QSO entry. This iteration builds upon previous versions like 2.1, which corrected an automatic _UTC date_ bug, and 2.0, which featured a full rewrite to resolve browser quirks and optimize search functions. The software's evolution demonstrates a commitment to functional stability and user interface refinement.
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Find out how much to adjust the length of a quarter wave whip or a half wave dipole rather than the outright cut-and-try method.
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Accurate calibration of your receiver and sound card is necessary for good results with the weak signal modes in use at LF. Modern receivers with master oscillators that are synthesized to provide all conversion frequencies greatly simplify the process. This article describes a method of making the necessary measurements and adjustments to an ICOM R75 receiver and a sound card, using the ARGO software
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Using a PC with soundcard as a VLF receiver, how to use your PC as a receiver for narrow-band signals in the VLF radio spectrum by DL4YHF
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A 38-foot Tristao Tower, similar to the U.S. Tower HDX538, was installed twice by the author, first in 1980 and then reinstalled in 1989. The resource details the challenges of self-performing heavy construction tasks like breaking concrete and digging a 3' x 3' x 6' deep footing, contrasting it with hiring professionals for the second installation. It highlights the financial and physical costs associated with DIY tower foundation work, noting a rebar cage cost of $65 in 1980 versus $150-$175 today, and the expense of tools for bending rebar. The content emphasizes the critical importance of obtaining building permits, recounting how a permit in Buena Park, California, nullified a neighbor's complaint about TVI. It also discusses the necessity of adhering to local building codes, such as the 1975 UBC and the subsequent 1985 UBC recertification requirement, which reduced the allowed antenna wind loading from 30 square feet to 20 square feet for the author's _KT34A_ Yagi. The footing depth also increased from 6 feet to 6.5 feet under the newer code. Practical advice includes hiring licensed contractors for specialized work, delaying antenna installation for a month after raising the tower, and verifying buried utilities before any excavation. The author provides specific examples of utility location services like _DigAlert_ in California, underscoring the legal and safety implications of neglecting this step. The narrative is grounded in personal experience, offering a realistic perspective on tower projects.
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Quick and Dirty CW Netiquette
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A nice post on Make: on homebrewing a multiband antenna for amateur radio portable operations
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In the VLF portion of the spectrum it is easy to listen to the emissions created by the Earth itself. These emissions are generated by many different mechanisms and are often beautiful to listen to. Coverage on LF and MF frequencies
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CMSK is a narrow-band weak signal digital mode for LF and MF ham radio bands defined by ZL2AFP. CMSK63 is the windows client program.
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PDF document for IC-7300 beginners. The ICOM IC-7300 is an HF + 6 meter, multi-mode, self-contained Software Defined Radio (SDR) transceiver with knobs, buttons and a touch screen. It also has a real-time spectrum display with pan adapter and water fall displays.
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For radio amateurs and electronics enthusiasts requiring specialized wiring solutions, Multi/Cable Corporation provides custom multi-conductor cable manufacturing services. They focus on made-to-order constructions, offering a broad range of specialty cable products including composite, instrumentation, electronic, flexible cord, thermocouple, high-temperature, and Mil-Spec wire and cable. Their capabilities extend to extensive customization of all cable components, ensuring precise adaptation to specific application requirements, which can be critical for bespoke shack setups or antenna control lines. With over 50 years in business, Multi/Cable emphasizes low minimum orders, quick turnarounds, and competitive pricing, making custom cable solutions accessible even for smaller projects. A case study highlights their role in helping an emergency vehicle lighting company expand offerings by providing versatile and cost-effective wire bundles, demonstrating their ability to support diverse technical needs beyond typical off-the-shelf options. They also provide reference data and guides on choosing conductors, insulation, and jacketing materials.
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Born as a companion transmitter for the Yaesu FRG-7 receiver has become a stand alone tramsmitter for 160 meters band
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This article is about a simple vertical end-fed-half-wave wire antenna for 10 meters that can be used in case of restricted space.
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Located in Port Richey, Florida in Pasco County, West Central Florida just Northwest of Tampa.
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An easy to build with a cheap HEMT FET Transistor Low noise preamplifier with FHX35LG based on JH0WJF design
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Modeling compact 160 meter antennas, inverted L, half wave dipoles and linearly loaded dipole
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Covers experimental work from VLF through laser by K3PGP, one of the EME pioneers.
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Providers of solar panels, photovoltaic systems, Solar Cells and Solar Renewable systems and education for the Do-It-Yourselfer
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This online WebSDR is located near Corinne, Utah, has coverage on all U.S. amateur HF, MF and LF bands, 2 meters, the bottom 1 MHz of 6 meters, and several shortwave broadcast bands.
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Antenna Systems & Solutions, Inc. carries antenna mounts, antenna guyed towers, antenna self-supporting towers, four legged towers, BX towers, poles, tower hardware, and wall mounts.
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A transceiver front-end protector in high signal level environments. An homemade RF limiter to protect your receiver front-end from high radio frequency.
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Layman level explanations of "seemingly" mysterious LF MF and HF propagation occurrences.
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An unconventional antenna family, the VHF/UHF Zigzag Dipole Antennas. Design, theory and practical construction, transformation and balancing with a half wave balun.
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An home made end fed half wave antenna with a tuner box by NG0R
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SFHRC - San Francisco Ham Radio Club, formed December 1,1998, to conduct activities to advance the general interest and welfare of Ham Radio in San Francisco and neighboring communities of the Bay Area.
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A vertical antenna project for the 7MHz made with some spare parts. Based on a broken 20 foot fishing pole, it is based on a good ground system made with radials and a capacitive hat done to increase the global radiation resistance of the antenna. A custom loading coil is also included in this project to perfectly tune the antenna to the CW portion of the 40 meters band.
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The **Solarcon A99** vertical antenna, a half-wave over a quarter-wave variable mutual inductance design, primarily serves the 11-meter CB band but also finds use on 10 and 12 meters for amateur radio operators. Its simple construction, consisting of three fiberglass sections and a 16 AWG radiating element, makes it an accessible option for new operators or those seeking an easy-to-install base station antenna without complex mounting requirements. Despite claims of 9.9 dBi gain being widely considered exaggerated, and a manufacturer rating of 2000 watts power handling often viewed with skepticism (with 300 watts suggested as a practical limit), the A99 maintains popularity due to its low cost and ease of deployment. It typically tunes to a 1.2-1.3 SWR out of the box, requiring minimal adjustment via its two tuning rings. Its high angle of radiation allows for effective local communication even when mounted at low heights, such as 8-10 feet off the ground. However, the A99 is known for significant RF bleed-over issues, particularly when operated with higher power or mounted close to residential electronics. While its internal design is often described as cheap, the antenna exhibits remarkable durability, frequently lasting a decade or more in various weather conditions. Its affordability and straightforward setup continue to make it a go-to choice for many radio enthusiasts.
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Yaesu FT817 all band, all mode handheld transceiver article.
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An economical dipole for simple QRP HF homebrew rigs
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by Jim Stafford, W4QO appeared in QRP Quarterly, Fall, 2006
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How to apply for a reciprocal license in Germany
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An 80m transceiver using just 14 parts plus crystal and earpiece
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A quarter wave antenna with dimensions for uhf and vhf bands
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Amateur Radio 40m 20m 15m Half Wave Fan dipole antenna project with part list, pictures and drawing. Includes the option to expand the antenna to cover the 80 meters band
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An home made FETer QRP transceiver for the 80 meters band
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Radio Cubana by Instituto Cubano de Radio y Television official site
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An end-fed-half-wave antenna matcher project based on a FT-82-43 core with a 100 pF and 45 pF capacitor in parallel
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FLMSG is a simple forms management editor for the amateur radio supported standard message formats. Form data can be transferred between computers either using standard internet email or via radio frequency broadcasts typically made by an amateur radio operator on your behalf.
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A handy solution to have a half wave antenna for fieldwork on a 12m fishing rod.
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What's all this stuff about LowFERs, MedFERs and HiFERs? What Is 'Part 15?'
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By by Larry Wolfgang WR1B in QST Archives at ARRL
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The Highland Amateur Radio Association (HARA) centers itself in Hillsboro, Ohio.
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This converter uses the popular NE602 mixer/oscillator chip and allows reception of signals below 500 kHz on a 3.5 – 4 MHz HF receiver
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Introduction to WSPR beacons. Article describe WSPR2 and WSPR15 beaconing mode and include a frequency reference table for both WSPR modes
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Unfilter LF output from the TH215/415 kenwood portable radio
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Marshall G. Emm, N1FN, meticulously examines iambic keying, dissecting its historical introduction in the late 1950s with transistorized electronic keyers and its purported advantages. The resource defines keying systems, electronic keyers, and various paddle types, including single-lever and dual-lever paddles, clarifying the distinction between iambic keyers and the iambic sending technique itself. It details the two main types of squeeze keying: true squeeze for alternating dot-dash strings and character insertion for specific elements within a character. N1FN critically evaluates the actual efficiency gains of iambic keying, referencing Chuck Adams, K7QO's, keystroke analysis. While a straight key to bug transition yields a 34.1% reduction and a bug to non-iambic keyer offers 16.1%, iambic keying provides only an 11% theoretical improvement. However, considering typical QSO text and Morse code's inherent optimization for common letters, the practical efficiency gain is estimated at a modest 4-6%. The article also highlights how iambic keying's reliance on precise timing gates can impose a speed limit, making it less effective above 40 WPM, where many operators revert to non-iambic methods or single-lever paddles.