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You can now build and run your own ADS-B ground station that can be installed anywhere and receive real-time data directly from airplanes on your computer

This circuit enables fair copy of strong 444 MHz signals, off a local repeater, using a 2m rig and a 1/4λ 70 cm indoor ground plane antenna.

The 160 meter ground plane is constructed from #10 stranded insulated wire available in most hardware stores. The feedpoints / tiepoints use PVC pipe T-sections Article by W1TR

Quarter wave groundplane antenna for 2 meters FM by AA1PG

A 30 Meter Quarter Wave DIY Ground Plane Antenna that loads up nicely also on 12 and 6 meters

The _ISS Detector_ Android application, with over 5 million downloads, offers precise predictions for visible passes of the International Space Station. It notifies users minutes before an overhead pass, integrating local weather conditions to ensure optimal viewing opportunities. The core functionality focuses on the ISS, but in-app purchases extend its capabilities to track other celestial and artificial objects. Optional extensions, available via in-app purchase, allow users to monitor dozens of amateur radio and weather satellites, providing real-time transmitter information and Doppler frequencies. Additional extensions cover _Starlink_ satellites, the _Hubble Space Telescope_, rocket stages, bright satellites, comets, and planets, expanding the scope beyond the ISS to a broader range of observable space phenomena. The app's interface is designed for ease of use, displaying pass times, directions, and elevation. It adapts predictions based on the user's GPS location, ensuring accurate local forecasts. The latest update, dated April 3, 2026, includes corrections for magnitude values and various speed and stability optimizations.

The Superantennas MP-1 portable HF antenna is analyzed for its design and field performance, particularly its high-Q loading coil and 3/8-inch mounting. The review details the antenna's construction, including an 8-inch vertical section, a large-diameter loading coil tuned by a sleeve, and a 4-foot whip that disassembles into six rods for transport. Initial testing with the supplied 10-foot ribbon cable "ground plane" yielded poor SWR and RF hot conditions, indicating an inadequate ground system. Further experimentation with longer radials and resonant counterpoises for each band improved matching and eliminated RF hot issues, but introduced significant operational complexity. The author notes the difficulty in optimizing both counterpoise length and coil setting without an antenna analyzer, and the sensitivity of the MP-1 to counterpoise deployment. The review also discusses the recommendation to tune for maximum received signals rather than minimum SWR, often necessitating an external ATU due to the antenna's typical low impedance. The **MP-1**'s critical dependence on resonant counterpoises for effective operation, especially when elevated, is highlighted as a major drawback for portable use. The author ultimately sold the antenna, concluding that despite its sound technical design, its fussy nature and the need for extensive counterpoise management or an ATU detract from its portability and convenience compared to simpler, less expensive dipole solutions. The **Superantennas MP-1** is deemed a flawed portable antenna, requiring considerable effort to achieve its claimed performance.

A 70cm ground plane antenna made with a 90cm of 1mm silver steel rod

The _Fuji-OSCAR 20_ (FO-20) amateur radio satellite, launched over six years prior, continues to operate reliably, despite a gradual decrease in its Nickel-Cadmium storage battery capacity and solar cell degradation. The satellite's power system can still supply approximately **10 W**, enabling operations. During the non-eclipse period, typically from mid-June through March, the satellite experiences a 0% eclipse rate, ensuring sufficient power generation. This allows for the potential operation of the onboard BBS, which had been previously suspended due to concerns about power shortages. An "eclipse rate" refers to the proportion of time a satellite spends in the Earth's shadow during each orbit. When the satellite's orbital plane is perpendicular to the sun's direction, the eclipse ratio becomes zero, meaning continuous solar illumination. Understanding these eclipse periods is crucial for managing satellite power budgets and scheduling operations, particularly for power-intensive functions like the BBS, which can now be considered for activation during periods of sustained solar exposure.

Designing and constructing a two-element receiving loop antenna array for HF operation involves specific considerations for achieving high directivity and noise reduction. This resource details a homebrew system comprising two 30-inch diamond-shaped loops, spaced 20 feet apart, which are fed through mast-mounted preamplifiers and passive signal combiners. The operational principle relies on adjusting phase delays between elements via precise _Belden 8241_ coaxial cable lengths, optimized for specific bands from 160m to 20m. Performance data, derived from _EZ-NEC_ modeling, illustrates consistent 90° azimuth-plane beamwidth and low take-off angles across the target bands, with _Receiving Directivity Factor_ (RDF) values comparable to a 300-foot Beverage antenna. The article presents detailed elevation and azimuth plots for 20m, 30m, 40m, 80m, and 160m, demonstrating the array's ability to provide strong response at low DX angles while also supporting _NVIS_ signals. Key components like the _DX Engineering RPA-1_ preamplifier and _DXE RSC-2_ signal combiner are discussed, alongside the importance of impedance matching to preserve antenna patterns. The construction emphasizes self-contained elements that do not require ground radials, offering a compact solution suitable for suburban environments and stealth installations, with a focus on optimizing receive performance independently from transmit antennas.

Launch of a hybrid rocket from high altitude by untsville Alabama L5 Society

Make them simple then Make them work. The LAZY H antenna is a general type of antenna that is in the curtain array family. By placing two 1 wavelength dipoles in a plane that is at right angles to the direction of maximum radiation and keeping the proper in-phase current condition to each element, you can achieve a high gain bi-directional antenna.

The G3JVL 6M ground plane vertical is a compact antenna that is ideal for portable operations. It packs away into a small bag only 1.3 metres long which is an ideal size for hand-baggage on aircraft.

Aircraft Scatter Sharp is a windows application to calculate and assist airscatter operations. Real-time capture and display of plane position data derived from internet plane servers, highlighting of aircraft near the ideal position for scatter, Real-time estimation of Doppler shift and its rate of change.

A short 3 element LFA Yagi for 50MHz with a 1.94M boom. This antenna has been designed in order to minimise the upward and downward lobes typically seen the the EL plane on Yagi antennas.

Operating on Airplane scattering. Scattering of radio signals by airplanes. An introduction to operating ariplane scattering, using aircraft to redirect RF that would otherwise be lost in space. Antenna Pointing, Doppler Shift/Digital Modes, using digital modes to operate airscatter.

This Field Day Vertical Antenna project is the result of many years of attending various field day sites and realizing that what was needed is a simple, easy to assemble vertical antenna. The design of this Field Day Antenna is not very novel and leverages ideas from Butternut verticals and ARRL publications. The one essential requirement was that the antenna can be raised by just one person. The design of this Field Day Antenna is an above ground mounted ground plane vertical.

Mounting on roof at the right ground level can greately impact on antenna performances because will affect the radiated angle of energy.

Three cell Lipo batteries for the FT-817 work really well, although not really sure about taking them on aircraft. The Lipos intended for use on RC Electric airplanes generally have a very low internal resistance and no internal protection against short circuit.

Mad your own simple FS meter. It is the simplest thing to make and is good enough to see if the antenna under test is radiating more power than your old ground plane, old mobile vertical or just radiating at all in a particular direction or in all directions.

QSO Procedure for Airplane Reflections, Reporting system and procedure, confirmation procedure and requirements for a complete QSO

This project details the construction of a compact, circularly polarized Quadrifilar Helix Antenna (QHA) designed for 146 MHz operation. The antenna features a 1/2λ1/2λ helical design with a 2.6:1 aspect ratio, providing 4.5 dB gain and a spheroid radiation pattern. It is ground plane independent and compatible with both vertical and horizontal polarizations, making it ideal for terrestrial and space communications. The design includes step-by-step instructions for building the antenna using readily available materials like aluminum rods, PVC pipes, and RG-58 coaxial cable. The antenna's performance has been validated through comparisons with commercial omnidirectional antennas, showing superior results.

A homemade quarter wave ground plane anntenna for 4 meters band.

The FT-991 is a nice small size and lightweight radio, it is perfect for portable operations. It can be carried along with a laptop computer as hand luggage in airplane. The weak point of this radio, is it does not have a separate RX antenna capability. Therefore i decided to add this feature. On the back side of the radio a BNC connector is added to connect the RX antenna and a switch is fitted to select between RX antenna or main antenna.

An cheap and efficient wire antenna for lower HF bands. This closed loop antenna, radiates perpendicular to its plane with a bi-directional radiation pattern. With a gain of 2 dB over a diplole it is a low noise sensible antenna. Requires a tuner if you want to use as a multiband antenna.

This page allows hams to design a vertical-plane delta-loop antenna for a single amateur HF band in different configurations. By choosing different feed-point positions, operators can observe variations in polarization properties, radiation patterns, and feed-point impedances. Users can generate radiation pattern plots, VSWR charts, antenna current diagrams, and Smith charts for their antennas over various ground types. Through adjusting the antenna's physical dimensions and refreshing the plots, hams can gain insights into the antenna's performance in the field. The page also discusses how elevation radiation patterns may change based on the antenna configuration and feed-point position.

Cloverleaf antenna is a circular polarized antenna which is way better than the cheap dipole antenna that comes with video transmitters and receivers. The Cloverleaf is a closed loop antenna which the signal and ground wires are connected. The cloverleaf antenna has 3 loops at 120 degree apart, and they are titled at 45 degree to horizontal plane.

Online impedance calculators grouped by types like Wire inductances, Toroid incuctances, Plane, PAD, Strap inductances, but even Core and Coax Inductances. Air core inductances and mutual inductance groups are also availbale. All these calculators let you input specific paramenters based on the inductor selected and will calculate specific incutance and related dimensions.

This article explains the trick of how to shorten and lengthen pairs of radials to make a 2-band ground plane antenna. Included is a "Table of Multi-Band Possibilities" covering the range of 6 to 40 meters.

Off Grid Ham discusses the benefits of mobile ham radio operation in addition to fixed or semi-fixed base stations. The article highlights the challenges of antenna placement on vehicles, emphasizing the importance of a good ground plane for optimal performance. Tradeoffs between performance and appearance are inevitable, especially with modern vehicles that have plastic body panels. Bonding the coax shield to the car frame is often necessary to establish a good ground plane. Mobile ham radio operation is a valuable option that fills in the gaps left by fixed stations, offering flexibility and convenience for hams on the go.

When installing a mobile antenna, optimal placement significantly impacts performance. Factors such as gain, antenna type, ground plane availability, mounting style, and environment must be considered. Antenna designs, such as 1/4 wave and 5/8 wave, have distinct radiation patterns ideal for specific settings—urban areas or flat terrains, respectively. Ground plane size requirements differ by frequency, impacting effectiveness. Among vehicle mounting options, the car roof center provides the best ground plane and minimal obstruction, ensuring peak performance, especially at higher frequencies like 800 MHz.

A guide to constructing a simple quarter-wave ground plane antenna, detailing design principles and providing dimensions for VHF/UHF bands

Operating amateur radio satellites presents unique challenges, particularly concerning antenna design and signal propagation. Juan Antonio Fernández Montaña, EA4CYQ, recounts his three-year journey into satellite communication, starting with initial guidance from EB4DKA. His early experiments involved a portable 1/4 wave VHF antenna with four 1/4 wave ground planes, designed for hand-held use to adjust polarity. This setup, paired with an FT-3000M transceiver, allowed full-duplex operation on **VHF** transmit and **UHF** receive, proving effective for early contacts on satellites like AO27, UO14, and SO35. EA4CYQ's experience highlights the critical role of coaxial cable loss and antenna polarization. After encountering significant signal degradation with longer RG213 runs, he experimented with a 1/2 inch commercial cable, noting improved reception but persistent fading due to varying satellite polarities. This led to the construction of an **Eggbeater II** antenna, an omnidirectional UHF design offering horizontal polarization at the horizon and circular right polarization at higher elevation angles. Subsequent modifications resulted in the directional **TPM2** antenna, which provided sufficient gain for LEO satellites with a wide 30-degree lobe, enabling consistent contacts from his home station. The article concludes with practical insights on the performance of the Eggbeater II for both UHF and VHF, and the TPM2 for UHF, emphasizing their utility for portable and fixed operations. EA4CYQ's journey underscores the iterative process of antenna development and the importance of adapting designs to overcome real-world propagation challenges in satellite communications.