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4 elements Yagi antenna for 28 MHz

10 Meter Beacon, 28.288 mhz Hurricane Uta USA

The Resonant Feedline Dipole (RFD) HF antenna design utilizes a single piece of coaxial cable and a stranded wire section, forming a 1/4-wavelength radiator. This configuration, based on a 1997 ARRL Handbook design (page 20.17), functions by RF traveling on the inside of the coax shield and returning on the outside, creating the second half of the dipole. A choke wound into the feedline prevents RF current from flowing back down the feedline. Construction details include using RG-58a/u coax for a 75m version, with a 1/4-wavelength section of stranded wire soldered to the center conductor. The document provides choke dimensions for RG-213, RG-8, and RG-58 coax across 3.5 MHz to 28 MHz, specifying cable length and number of turns. Dipole dimensions are also tabulated for frequencies from 3.6 MHz to 28.4 MHz, listing overall length and individual leg lengths. Field tests included deployment near Bryson City at 5 feet off the ground and as a sloper during WCARS Field Day in Asheville, yielding successful local and regional contacts.

The NCDXF/IARU International Beacon Project operates a worldwide network of 18 high-frequency radio beacons, continuously transmitting on 14.100, 18.110, 21.150, 24.930, and 28.200 MHz. These beacons, initially launched in 1979 with a single station and expanded to the current 18-beacon system in 1995, provide reliable signals for both amateur and commercial users to assess current **ionospheric propagation** conditions. The system's design, construction, and operation are managed by volunteers, covering hardware and shipping costs. The resource details the evolution of the beacon network, including the transition from Kenwood TS-50s transmitters to Icom IC-7200 radios with a new controller design implemented in 2015. It explains how listening for these 100-watt signals, transmitted to vertical antennas, allows operators to determine band openings and optimal propagation paths globally. The content also references three QST articles providing historical context and technical specifics of the beacon project. Practical information includes methods for identifying transmitting beacons via a schedule or specialized software like FAROS and Skimmer, which integrates with the **Reverse Beacon Network** for automated monitoring.

A 27-28 Mhz quad loop antenna by Bernard Mourot F6BCU in french

A nice loop antenna project for 28 MHz with schematic diagram, construction details and a complete video instruction

Optimizing the ZS6BKW antenna for full HF band coverage often requires specific modifications beyond its standard configuration. This resource details several enhancements, beginning with a simple series capacitor to improve 80m SWR, a technique W5DXP found effective for permanent installation due to its minimal impact on higher bands. Further improvements include a 10-inch parallel open stub for 10m resonance, shifting the frequency to 28.4 MHz with an SWR of approximately 1.8:1, a practical solution for Technician class operators. The document then explores a switchable matching section, adding or subtracting one foot of ladder line at the 1:1 choke-balun, which significantly impacts higher frequency bands and eliminates the need for a tuner on 17m. W5DXP's _AIM-4170D_ antenna analyzer measurements confirm these effects. More advanced modifications involve a parallel capacitor for further 80m SWR reduction, requiring remote switching for multi-band operation, and relay-switched parallel capacitors at specific points on the 450-ohm matching section to achieve low SWR on 60m, 30m, and 15m. These detailed steps, including _Smith chart_ analyses for the challenging bands, aim to transform the ZS6BKW into a truly all-HF-band antenna, reflecting W5DXP's practical experience in antenna tuning.

Presents a QRP AM/CW transmitter project specifically designed for the 10-meter band, utilizing a crystal oscillator and a collector-modulated AM oscillator. The design employs a 2N2219(A) transistor in a Colpitts configuration, generating 100 to 350 mW of RF output power depending on the 9-18 Volt supply voltage and modulation depth. Frequency stability is maintained by a 28 MHz crystal, with fine-tuning possible via a Ct1 trimmer capacitor for approximately 1 kHz adjustment. The resource details the RF oscillator stage, implemented with a 2N2219 NPN transistor, emphasizing frequency stability and low power dissipation. It also covers the amplitude modulation stage, managed by a 2N2905 PNP transistor, which impresses audio information onto the carrier. Selective components (C3, C4, C7, C5) enhance voice frequencies within a +/- 5 kHz bandwidth, and modulation depth is controlled by R2 and R3. The project includes a 3-element L-type narrow bandpass filter (Ct3, L3, C10) to suppress harmonics and ensure a clean output signal. The project provides a complete schematic diagram, a comprehensive parts list including specific capacitor, resistor, and inductor values, and construction notes for the coils (L1, L2, L3). It also offers practical advice on enclosure requirements, suggesting an all-metal case or a PVC box with graphite paint for RF shielding. Operational parameters such as current draw (27mA@9V to 45mA@16V) and input impedance (50 Ohms) are specified, alongside guidance on antenna matching and the importance of a valid amateur radio license for 10-meter band operation.

This is a prototype of the WA4DSY 56KB RF modem. It is intended for use on amateur packet radio networks. The modem generates RF in the 28 to 30 mhz range and requires and linear transverter to convert the signal to a UHF or microwave ham band

A 5 element yagi beam antenna for ten meters band with full dimentsions, eznec file and coax match informations for 50 ohms feed line

An homebrew project for a 4 elements yagi monoband antenna for the 10 meters by 9M2MSO

2 transistor transceiver for 28MHz CW

The resource details the construction of a multiband trap-style Inverted-V antenna designed for operation on 3.5 MHz, 7 MHz, 14 MHz, 21 MHz, and 28 MHz. It presents specific winding data for the traps, including the number of turns, wire gauge, and coil former dimensions, crucial for achieving resonance on the target bands. The document provides a parts list and a diagram illustrating the antenna's physical layout and trap placement. It outlines the process for building the traps using PVC pipe formers and specifies the required capacitor values for each trap. The design emphasizes a practical approach to achieving multiband operation with a single feedline, a common goal for HF operators with limited space. The document includes a table with antenna segment lengths for each band, allowing for precise replication of the design. It also offers insights into tuning and adjustment, ensuring the antenna performs optimally across the designated amateur radio bands.

An SSB radio for the HF bands will be presented. Featuring 12 to 20 Watts of output power (depending on DC supply), full DDS frequency generation, covering 6 major frequency bands (1.8, 3.5, 7, 14, 21 and 28 MHz) within the short wave amateur radio spectrum. The rig also features colored LCD and front panel backlight.

21 28 and 50MHz three bands whip antenna by JA1HWO

Pictures and design plan of a 28 MHz - 70 MHz transverter 3Watts in - 8Watts out by 9A2SB

This project is based around the recent HF1 QRP transceiver by Ashhar Farhan, VU2ESE. The transceiver is an interesting SSB design with wide tuning range from 0-30MHz and should cover several amateur bands. The schematic for the transceiver can be found on the Minima mail list in this post with a PDF attachment

Rules of CQ World Wide RTTY Contest. The CQ World Wide RTTY DX Contest take place last full week-end of September, inviting amateur radio operators globally to connect across various CQ zones and countries. Participants will operate on five designated bands: 3.5, 7, 14, 21, and 28 MHz, exchanging RST reports and zone numbers. Scoring is based on QSO points multiplied by zone, country, and QTH multipliers. The contest encourages innovation in operating strategies while adhering to established rules to ensure fair competition among entrants.

This project involves the construction of a 5 Watt Morse code beacon transmitter that operates in the 28.200 to 28.300 section of the 10 Meter Amateur Radio band. The beacon controller uses an Arduino Uno microprocessor board to produce the three signals that control the transmitter.

An easy to build and extremely high performance antenna, works perfectly on all HF bands 3.5-28 MHz with some compromises, it is basically an half wave dipole for 40-80 meters, an LC circuit or trap 40 meters allows you to use a single radiating element.

This project is a Software Defined Radio Receiver. It has a frequency range of 24MHz 1.2GHz. It can demodulate AM, FM, USB, LSB with selectable bandwidths of 600, 2400, 2800, 3200 and 6400Hz. Using a simple RTL-SDR Dongle and Raspberry Pi 3 computer using GNU RADIO

The article, "Using 75 Ohm CATV Coaxial Cable," details methods for employing readily available 75-ohm CATV hardline in standard 50-ohm amateur radio setups. It addresses the inherent impedance mismatch and practical considerations, such as connector compatibility, for hams seeking cost-effective, low-loss feedline solutions. The resource specifically contrasts common 50-ohm cables like RG-8, RG213, and _LMR-400_ with 75-ohm hardline, highlighting the latter's lower loss characteristics, particularly at VHF and UHF frequencies. It explores two primary approaches to manage the impedance difference: direct connection with an acceptable SWR compromise and precise impedance transformation. The direct connection method acknowledges that a perfect 1:1 SWR is not always critical, especially when using low-loss coax. For impedance transformation, the article explains the use of half-wavelength sections of coax to reflect the antenna's 50-ohm impedance back to the transmitter, noting its single-frequency effectiveness. It also briefly mentions transformer designs using toroid cores and a technique involving two 1/12 wavelength sections of feedline for broader bandwidth. The content further clarifies the concept of _velocity factor_ for calculating electrical versus physical cable lengths, providing a generic formula for precise length determination. It notes that while half-wave matching is practical for 10 meters and above, it can result in excessively long runs for lower bands like 160 meters, potentially adding **250 feet** of cable. The article also mentions achieving a usable bandwidth of 28.000 MHz up to at least **28.8 MHz** on 10 meters with specific transformation techniques.

A 102-inch vertical whip, commonly a CB antenna, forms the core of this low-profile 10-meter antenna design, optimized for the 28 MHz band. The construction details specify three 8-foot radials made from scrap wire, connected to a common point. This simple yet effective setup is designed for ease of construction and deployment, making it accessible for operators with limited space or materials. The design emphasizes using readily available components, including PVC pipe for the mast and a SO-239 connector for the feedline, ensuring a straightforward build process for a resonant quarter-wave vertical. Field results indicate that this antenna provides good performance for local and DX contacts on 10 meters, despite its compact footprint. The author, N8WRL, shares practical insights into its construction and tuning, highlighting its suitability for temporary or permanent installations where a full-sized antenna might be impractical. Comparisons to more complex designs suggest that this low-profile vertical offers a respectable signal-to-noise ratio and effective radiated power for its size, proving that simple designs can yield satisfying on-air results.

What constitutes the ideal 28MHz beacon from the listener's perspective by G0AEV

Solving interference from television channel 11 on 144MHz transverters by Chris Cox, NØUK, G4JEC

Operating 28.249 MHz and 50.074 MHz from Bozeman, Montana

Construction of 28 MHz to 144 MHz Transmitting and Receiving Converter by KP4MD

144 MHZ to 28 MHZ 2nd Down-Converter for AO-40 Sat

28.2575 MHz Beacon from Lake Constance water works Germany

Much information about 50 Mhz and 2 meters : log , info , links .Also J28VS log.

10 meter 28.286 mhz 100 milliwatt Beacon

50Mhz 28Mhz 13.5Mhz amateur radio propagation beacons by K6FRC

Beacon website of WE4S, Grady Donaldson, located in McDonough, GA. EM73TM.

This DIY vertical multi-band Windom antenna offers a practical and effective solution for amateur radio enthusiasts seeking a versatile and compact antenna for HF communications. Its simplicity of construction, multi-band capability, and favorable performance make it a valuable addition to any radio shack. The article provides detailed instructions on constructing the antenna and balun, along with diagrams and component specifications. Field tests demonstrated successful contacts with stations across Europe and North America on 14, 18, and 28 MHz. The antenna exhibited comparable performance to a W3DZZ dipole and outperformed a Cobweb antenna on 18 MHz. Low noise levels were observed, effectively suppressing background noise.

Amateur radio station c31lj andorra 28.256 MHz

A 10 Meter Beacon on 28.222 MHz

How to setup and configure the buddipole antenna in the J-Pole mode for the six meter band

This transverter was built in 1994 and include in this page a pdf with circuit board, and a version of this project for 70MHz.

The world's oldest beacon OZ7IGY in JO55WM 28 MHz to 24 GHz.

Details the Highline Amateur Radio Club (HARC), an organization dedicated to public service through Amateur Radio and community engagement for radio enthusiasts. The club conducts a monthly general meeting on the 4th Saturday at 10 AM at Burien Fire Station 28. HARC also hosts a weekly net on Tuesdays at 7:30 PM, operating on **146.660 MHz** with a -600 kHz offset and a 103.5 Hz **CTCSS tone**. Additionally, members gather for a weekly breakfast on Fridays at 9:30 AM at Tuscany at Des Moines Creek. The resource provides current weather conditions for Burien, WA, displaying temperature, wind chill, and a three-day forecast from the National Weather Service Seattle/Tacoma Office. It also links to the latest ARRL Newsletter, noting a system breach in May 2024 affecting archived links. The club's activities include regular meetings, on-air nets, and social gatherings, supporting local amateur radio operations and community involvement.

Located in Eton, GA tx on 28.238 Mhz

Quads beams consist of 2 1 wavelength (approximately) loops, ordinarily arranged so that one is the driven element and the other is the reflector. In this project author explains how to build a two element Quad Antenna for the 28 MHz.

The ZS1J/B beacon operates on 28.2025 MHz with 5 Watts output to a half-wave, end-fed vertical antenna, initially installed in 1977 as ZS5VHF near Durban. The 10-meter transmitter is a modified 23-channel CB radio, and the identification keyer uses a diode matrix unit with TTL ICs from the same era. After relocation to Plettenberg Bay in 1993, the beacon has been in continuous service, with additional QRP transmitters later installed for other bands. In 1994, a single-transistor, 80-meter, 0.5-watt QRP transmitter with a half-wave dipole was added on 3586 kHz, followed by a 160-meter, 0.5-watt unit on 1817 kHz. A 30-meter, 0.5-watt transmitter was installed in 1996, operating on 10.124 MHz. In 2002, a 40-meter QRRP beacon on 7029 kHz, with an output of 100 microwatts, achieved DX reports up to 1100 km from ZS6UT in Pretoria. Best DX reports for the 80m and 160m beacons came from 9J2BO.

On 28.219 Mhz it puts out a whopping 3.85 watts into an inverted V dipole at about 30 ft.

Running from Rome area at 28321 Mhz

The Baofeng UV-5R handheld transceiver, introduced around 2012, operates across the 2-meter (144-148 MHz) and 70-centimeter (420-450 MHz) amateur bands, offering dual-band receive and transmit capabilities. This review provides an early assessment of the radio's form factor, user interface, and general performance, noting its compact size and the inclusion of a **VFO/Memory mode** button for frequency management. The device supports both FM and narrow FM modes, with a reported power output of 4 watts on VHF and 3 watts on UHF, making it suitable for local simplex and repeater operations. Key features discussed include its 128-channel memory capacity, a built-in VOX function, and a **DTMF keypad** for tone dialing and repeater access. The review highlights the radio's ability to scan frequencies and memories, along with a dual-watch function allowing simultaneous monitoring of two frequencies. Battery life is addressed, with the standard 1800 mAh Li-ion pack providing several hours of operation depending on transmit usage. Initial impressions cover the radio's construction and the clarity of its LCD display, which shows both A and B band frequencies.

Gimme Five reloaded, a compact 5 band QRP SSB transceiver in SMD technology. This unit covers 5 bands within the amateur radio spectrum (3.5, 7, 14, 21 and 28 MHz). Receiver is a single conversion unit with an interfrequency of 9 MHz. Transmitter uses 5 stages and has got a power level of 10 watts PEP output.

28,227.5 MHz, from JN55VF first "IW" prefix beacon "ON THE AIR" activated from Italy

TX on 28.289MHz since 1992