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DK5AI amateur radio station active on EME and SSTV.

Designing and constructing portable wire antennas for HF operations, this resource explores several configurations including the _foldback dipole_ for space-constrained setups and an inductively shortened dual-band dipole for 20m and 40m. It details the calculation of inductance for shortened elements, providing a Visual Basic 6.0 program screenshot that illustrates determining coil parameters like turns and length for a **25.5 uH** inductor. The document emphasizes practical considerations such as adjusting wire lengths for optimal SWR, noting that a dual-band dipole achieved SWR below 2:1 on both 20m and 40m, with careful adjustment bringing it under 1.5:1. Further, the resource describes a half-wave antenna matched with a coaxial stub, a method often referred to as the _Fuchskreis_ in German amateur radio circles, to transform the high feedpoint impedance to 50 Ohms. This monoband solution, for a 20m application, uses a stub length of **2.98m** (0.216 lambda multiplied by coax velocity factor) and a shorted stub of approximately 48cm. The coaxial stub design is highlighted for its resilience to ground proximity, allowing it to be rolled up or laid on the ground with minimal SWR impact, making it highly suitable for portable QRP operations.

Antenna tuners are crucial for matching the impedance of antennas to the 50 ohm output impedance of transmitters. The _LDG Z-11 Pro_ is an automatic antenna tuner designed to handle up to 125 watts, making it suitable for a wide range of amateur radio applications. Its compact form factor allows it to pair well with transceivers like the _FT-857D_, providing a portable solution for operators who frequently change locations or setups. The tuner covers the 80 through 6 meter bands, offering a broad impedance match capability. Although it struggles with some loads, it performs well with typical ham antennas, even managing to load an 80 meter dipole on 6 meters. One of the standout features of the _Z-11 Pro_ is its 8000 memory slots, which enable it to remember successful matches and quickly retune when revisiting frequencies. This memory function significantly reduces tuning time, often to less than half a second. The unit is well-constructed, with improved pushbuttons and a sturdy metal case that offers good shielding. However, users should be aware of potential RFI issues and the lack of a power switch, which requires disconnecting the power cord to turn off the unit completely. Overall, the _LDG Z-11 Pro_ is a user-friendly and cost-effective tuner, offering advanced features that enhance its utility in various amateur radio setups.

VHF, UHF and Satellite Antennas for Government, Commercial and Amateur Radio Made in Nebraska USA

End-Fed Half Wave matching unit project, based on a FT140-43 with SWR plot tests made using capacitor and without.

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.

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.

If you're driving around town listening to the buzz and engine whine blues, pick up this free pub and help yourself enjoy the music. Includes troubleshooting techniques and helpful hints.

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.

Article by N6LF on a top band vertical antenna array system

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.

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

Florida Alfa Tango d'Alsace.

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

ON6MU Low Power amplifier

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.

Quick and Dirty CW Netiquette

A nice post on Make: on homebrewing a multiband antenna for amateur radio portable operations

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.

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.

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

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.

Born as a companion transmitter for the Yaesu FRG-7 receiver has become a stand alone tramsmitter for 160 meters band

Located in Port Richey, Florida in Pasco County, West Central Florida just Northwest of Tampa.

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.

An easy to build with a cheap HEMT FET Transistor Low noise preamplifier with FHX35LG based on JH0WJF design

Modeling compact 160 meter antennas, inverted L, half wave dipoles and linearly loaded dipole

The G5RV junior Half Size antenna by kc8hps

Covers experimental work from VLF through laser by K3PGP, one of the EME pioneers.

Providers of solar panels, photovoltaic systems, Solar Cells and Solar Renewable systems and education for the Do-It-Yourselfer

An unconventional antenna family, the VHF/UHF Zigzag Dipole Antennas. Design, theory and practical construction, transformation and balancing with a half wave balun.

A transceiver front-end protector in high signal level environments. An homemade RF limiter to protect your receiver front-end from high radio frequency.

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.

Layman level explanations of "seemingly" mysterious LF MF and HF propagation occurrences.

An home made end fed half wave antenna with a tuner box by NG0R

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.

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.

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.

Yaesu FT817 all band, all mode handheld transceiver article.

An economical dipole for simple QRP HF homebrew rigs

During a club's "Filetto Day" event, a comparative field test was conducted between a **Buddipole** antenna and a homemade 20/40-meter wire dipole. The author, IW5EDI, performed this personal evaluation from a mountain top at 1500 meters above sea level, utilizing a Yaesu FT-857D transceiver to switch between antennas. The observations on the 20-meter band indicated that the wire dipole consistently delivered significantly stronger signals compared to the Buddipole. Additionally, the Buddipole exhibited higher levels of **QRM** during the listening tests. The commercial Buddipole, known for its multiband capability and compact size with a self-supporting tripod, was contrasted with the simpler, larger wire dipole, which required a fiberglass fish pole for support. This direct comparison highlights practical differences in performance and deployment between a popular portable commercial antenna and a basic wire antenna in a real-world operating environment.

by Jim Stafford, W4QO appeared in QRP Quarterly, Fall, 2006

An 80m transceiver using just 14 parts plus crystal and earpiece

How to apply for a reciprocal license in Germany

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

A quarter wave antenna with dimensions for uhf and vhf bands

An home made FETer QRP transceiver for the 80 meters band

Radio Cubana by Instituto Cubano de Radio y Television official site

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

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.