Search results
Query: 40 m
Links: 933 | Categories: 14
Categories
- Antennas > 40M > 40 meter Dipole Antennas
- Antennas > 40M > 40 meter Loop Antennas
- Antennas > 40M > 40 meter Magnetic Loop Antennas
- Antennas > 40M > 40 meter Vertical Antennas
- Antennas > 40M
- Radio Equipment > HF Transceivers > Kenwood TS-440S
- Radio Equipment > HF Transceivers > Kenwood TS-940S
- Radio Equipment > Receivers > Ten-Tec RX-340
- Antennas > 40M > 40 meter Delta Loop Antennas
- Antennas > 40M > 40 meter Yagi Antennas
- Radio Equipment > HF Vertical Antenna > Butternut HF2V
- Radio Equipment > HF Vertical Antenna > Cushcraft R8
- Antennas > Morgain
- Antennas > Vertical
-
Learn how to improve reception on the hf bands by setting up a noise cancelling system that nulls out local interference. This article describes a system using a 'Main Station Antenna' to receive a wanted signal and associated QRM, and an 'Auxiliary Antenna' to pick up unwanted interference. Gain and phasing controls are used to reduce/remove interference, leaving only the wanted signal. Tips are provided based on the author's personal experience, applicable to commercial noise cancelling products, kit form, or homebrew setups. Discover the importance of configuring the 'Auxiliary Antenna' to optimize your system and improve readability of wanted stations.
-
A small magnetic loop antenna, often employed by hams facing antenna restrictions or high local RFI, offers a compact solution for HF operation. This resource details the construction of a foldable magnetic loop designed for the 40m through 17m bands, emphasizing its high-Q factor and _Faraday coupling_ for effective noise rejection and narrow-band filtering. The guide outlines material selection, advocating for copper over aluminum to maximize efficiency, and provides insights into the physics governing its operation, including impedance matching and resonance principles. Practical application of this antenna design is particularly beneficial for QRP enthusiasts and portable operators seeking a stealthy, high-performance antenna. The construction process includes specific details for a 1-meter diameter loop, a 140pF variable capacitor, and a _gamma match_ for impedance transformation. Performance comparisons suggest that while a full-size dipole might offer slightly better gain, the magnetic loop's ability to mitigate local noise often results in a superior signal-to-noise ratio, making it a viable option for challenging RF environments.
-
A vertical antenna project for POTA operations. This shortened antenna is aimed to work from 20 to 40 meter band implementing a loading coil, with an additional wire lenght, determined by on field testing and tuning.
-
A KiwiWebSDR from Dimapur Nagaland India running a loop antenna for HF bands
-
Hostilog, developed by DF1LX using Python 3.5 and PyQT5, is a logging application designed for high-speed QSO data entry, achieving rates of 300–400 QSOs per hour from handwritten logbooks. The software prioritizes keyboard input, minimizing mouse usage for efficiency. It incorporates a cluster window with RegEx filtering capabilities and facilitates UDP transfer of QSO data to _DXkeeper_ from the _DXLab Suite_. The program supports basic rig control via _Hamlib_, with configuration examples provided for radios like the TS-590S using `rigctld`. Hostilog can process 50,000-line ADIF files in under 10 seconds and includes features for combining and sorting ADIF data. While primarily a Windows application, it runs under _WINE_ on Linux, with specific notes on Ubuntu compatibility. Recent updates, including a version from August 28, 2024, address bugs and improve UI, with documentation available in both German and English.
-
Learn how to build your own QRPGuys DS-1 40-10m short vertical antenna for ham radio operators. This page provides detailed instructions on constructing this antenna, which covers the 40 to 10-meter bands. Whether you're a beginner looking to get started with antenna building or an experienced ham radio operator looking for a new project, this resource is useful for anyone interested in DIY antennas for portable or QRP operations.
-
-
Online QSL archive counting 13400 QSL scanned and indexed online with a searchable database
-
This blog post by VE3VN discusses the design and performance of a 40-meter reversible Moxon antenna. The antenna provides coverage between southeast to west by default, with the ability to reverse for coverage from east to northwest. The post explains how the antenna performs well in various directions, focusing on the Caribbean, South/Central America, the US, and Europe. Detailed measurements and design considerations are shared, highlighting the accuracy of the model and the critical importance of coil inductance. The post also mentions the use of NEC5 for accurate modeling. Overall, this detailed discussion provides valuable insights for ham radio operators looking to optimize their antenna setup.
-
The author describes his experience building and using a Beverage antenna for the 40-meter band. Despite encountering some challenges, the antenna offered some improvements in receiving stations compared to a 3-element inverted Vee antenna. The Beverage antenna showed a significant daytime signal-to-noise ratio improvement and received signals better than the Vee antenna. However, the front-to-back ratio was not ideal, and the transmit power seemed to affect the Beverage antenna. Overall, the author concludes that the Beverage antenna might be more suitable for locations with higher noise levels. The total cost of the antenna was around 30 Euros.
-
A half wave wire that is tuned for resonance on 80m will NOT be resonant on 40m despite a precise harmonic relationship between the two bands. The End Effect is caused by a capacitive coupling between an unterminated wire end and the ground.
-
The 8m ISM band, a unique frequency range between 10m and 6m, holds potential for amateur radio enthusiasts, yet it remains largely unallocated. This spectrum offers fertile ground for research and self-training. The author's experience with low-power transmissions and WSPR testing highlights the band's capabilities and the need for a narrow, speech-free amateur allocation to encourage experimentation. Discover the world of 8m ISM radio exploration and its future possibilities.
-
This is a plan for an optimized element UHF Yagi Antenna for UHF Bands featuring a 9dBd forward gain, a 13 dB front-back ratio, and a bandwith of 10 MHz on the 430-440MHz range.
-
The Dipole Bazooka Antenna for 40 meters is a popular choice among amateur radio operators. Its design allows for easy construction using materials like RG58 coaxial cable and PVC. Measurements are calculated using specific formulas; for instance, at a frequency of 7,100 MHz, the total length is approximately 19.74 meters. This antenna offers a performance range of 97% to 99%, with an impedance of 49 to 52 ohms. Additionally, it can handle up to 1 kW of power and requires no modifications for connection.
-
Designed for the FT-817, this audio speech compressor, centered on the Analog Devices SSM2165, offers a 40 dB compression range, enhancing signal power. Built externally with the SMD version to preserve warranty, the circuit interfaces smoothly with electret microphones. Testing shows a 6 dB average power increase. Adaptable to rigs with electret microphones, it maintains unity gain and 40 dB compression.
-
The Portable EFHW antenna for the 40, 20, 15, and 10-meter bands utilizes a broadband transformer with a 1:49 ratio, designed on a PCB by either Jan or DL2MAN. The design incorporates an **FT114 core**, offering an alternative to the FT82 core. The antenna requires precisely 20.5 meters of DX Wire Ultralight for optimal performance. Additional components include DX Wires "Dyneema" 1mm rope and 1mm bricklayers string for structural support. The SWR plot indicates performance at two elevation heights: 5.5 meters (blue line) and 4 meters (yellow line), demonstrating optimization for low-elevation portable use without poles. The antenna's components, including spool and rope tensioners, are available for 3D printing, with spool dimensions scaled to 130% for a length of approximately 110mm. The design emphasizes simplicity and portability, suitable for field deployment.
-
From March 2 to March 11, 2018, a Norwegian team operated as Z2LA from Zimbabwe, focusing on 160m through 10m bands using SSB and CW modes. The operation, described as "holiday style," aimed to provide contacts for DXers worldwide seeking a rare DXCC entity. Key equipment included a SUNSDR PRO II, an Elecraft KX3, and an Icom 706 MK2G as a spare radio, supported by two Juma 1000 amplifiers for robust signal output across the bands. Antenna systems were tailored for multi-band operation, featuring an Inv L for 160m and 80m, sloping dipoles for 30m/40m, and a _Hexbeam_ from SP7IDX Technology covering 20m to 10m. For improved reception, the team deployed a SAL 30, two reversible BEV antennas from remoteqth.com, and a BOG from K1FZ, enhancing their ability to hear weak signals. QSL information directs operators to Clublog for log search and M0OXO Charles for OQRS, explicitly requesting no bureau cards. The team comprised LA7THA Rune, LA7WCA Arne, and LA9VPA Thor, successfully making numerous contacts and contributing to the DX community's pursuit of _Zimbabwe_ as a DXCC entity.
-
The Butternut HF2V, originally a two-band vertical antenna for 80m and 40m, was enhanced by the user to include 30m and 20m bands for better digimode DX work during the solar minimum. The additions used components adapted from the HF6V and innovative methods for the 20m addition, either through a parallel vertical element or a lower-mounted independent element, minimizing band interaction. This modified four-band antenna now supports high power across popular HF bands using a single feedpoint.
-
PH0NO conducted field tests comparing a mobile antenna (DX-UHV) to an end-fed half-wave wire. Results on 20m showed the end-fed wire outperforming the mobile antenna, with a significant difference in signal strength. On 40m, the end-fed wire surpassed the mobile antenna in spots and reach. While the mobile antenna is more practical, the end-fed wire offers superior performance. Further testing is planned.
-
This page provides guidance on designing an End-Fed Half-Wave (EFHW) or Random-Length antenna for amateur HF bands, such as 80 or 40 meters. The content explains how to optimize the antenna for multi-band use and match it to a 50-ohm system using an unun. Hams can generate radiation patterns, VSWR charts, and antenna current diagrams for their customized antenna designs. Understanding how antenna dimensions affect performance is essential for successful field operations. The page caters to ham radio operators looking to build efficient and effective HF antennas for their stations.
-
A multi-band trapped dipole antenna working on 20, 40, 75 and 160 meters band. This project implement a 20 meter trap unadilla reyco KW-20, 40 meter trap Unadilla Reyco KW-40 and a HI-Q 1:1 balun feed.
-
The PicoFox is a versatile fox transmitter for 2-meter ham radio operators, built around the RP2040 microcontroller. With open-source hardware and software, it can be customized to suit your needs, from APRS to other digital modes. This fully assembled transmitter comes with a rechargeable battery and antenna, ready for use. The design allows for easy addition of features like sensors or interactivity. Modulation is handled in software for smooth FM output, with ample CPU, flash, and GPIO available. Configure your PicoFox by connecting it to a computer via USB and adjusting settings in a text file. Explore the possibilities of this innovative transmitter for your amateur radio projects.
-
Automatically input GPS location data from an Android device to the transceiver, Compatible with IC-7100, IC-9100, IC-9700, ID-4100A/E, and ID-5100A/E.
-
Homemade portable transceiver for the 40 meters band.
-
This project addresses the need for a 50 MHz Amplifier providing substantial power for Australian "Advanced Licensees" permitted to use 400W PEP in the 52-54 MHz band. In regions limited to 100W PEP due to TV channel usage, this initiative aims to enhance power output for transceivers with lower capabilities on the 6m band.
-
Nuts & Volts, founded in 1980, began as an advertising-based newsprint and evolved into a leading electronics magazine. A major shift came in 1992, introducing content-rich articles, columns, and DIY projects, cementing its role for hobbyists and professionals. Reformatted in 2003 to standard magazine size, it now averages 100 full-color pages on high-quality paper. Celebrating 40 years, Nuts & Volts remains the longest-running U.S. electronics publication, with loyal readers and advertisers since the 1980s. Its diverse topics span robotics, circuit design, automation, microcontrollers, and more, appealing to all skill levels.
-
The recognition of telegraphy masked by noise at 40 and 80 signs/min telegraphy speed was studied in 10 normal-hearing subjects at different sound pressure levels (25-85 dB SPL in steps of 5 dB) as well as at different test frequencies (2000, 1000, 800, 630, 500 and 250 Hz). The ability to recognize the signs varied with varying SPL. Recognition for most of the subjects was best at an SPL close to 70 dB. All subjects improved their recognition as the frequency was lowered to 500 Hz, some even at 250 Hz. These facts should be taken into consideration when training telegraphy operators as well as in the construction of radio receivers to permit listening at low frequencies. Furthermore, the critical ratio was calculated at the different test frequencies.
-
Ferrite E-cores offer a practical solution for constructing baluns, especially when connectors are already mounted on cables. These cores, commonly used in mass-produced pulse transformers, allow for multiple turns without dismounting connectors, making them ideal for control and power supply cables. The material of E-cores is generally suitable for common mode baluns up to 15 MHz, providing a cost-effective option for amateur radio operators. E-cores can often be sourced from old switch-mode power supplies, adding to their appeal for those looking to utilize existing resources. A notable example involves a balun on a USB cable using a Ferroxcube E 32x16x9, 3F3 core with four turns, secured by three cable ties. This setup demonstrates the ease of construction and stability achievable with E-cores. Another example features a balun with eight turns of shielded cable with RCA connectors on the same core, achieving 140 uH inductance at low frequencies. The impedance plot for this configuration is measured between the shield ends, illustrating the effectiveness of E-cores in practical applications. The article includes detailed figures and descriptions, providing valuable insights into the construction and application of baluns using ferrite E-cores. These examples serve as a guide for amateur radio enthusiasts looking to enhance their setups with cost-effective and efficient solutions.
-
A 40 dB tap attenuator taht need only dissipate 2.3 watts, while delivering the same 0.02 watts to the input sensor.
-
Demonstrates the construction and portable deployment of a 40-meter horizontal loop antenna, often referred to as a "Sky Loop" or "DX-Buster." The design adapts a full-wavelength horizontal loop for field use, eliminating the need for traditional insulators by employing four 5-meter heavy-duty _squid poles_ and metal post bases for support. This setup facilitates rapid assembly, crucial for portable operations, with the antenna wire length specified at approximately 43-45 meters for optimal 40-meter band performance. The resource details the specific construction methodology, including winding the antenna wire around rubber caps on the squid poles and securing it with electrical tape. It provides a parts list and assembly techniques, focusing on minimizing components for ease of transport and quick setup. The article, originally published in the February 2013 edition of the Central Coast ARC "Smoke Signals" magazine, reflects practical experience. This documentation offers a field-deployable 40-meter loop antenna solution, utilizing readily available components like fiberglass squid poles. It presents a practical approach for operators seeking a robust, portable antenna for the 40-meter band, emphasizing simplicity and efficiency in its design and deployment.
-
The small receiving loop (SRL) is a versatile and efficient antenna that can be simply built from common materials. It is designed for reception on the MF and HF bands and may be put in a variety of shapes and sizes. Despite its unusual installation, the porch loop in this case operated admirably, producing several DX spots on the 40m band. The SRL can be a great option for people looking to boost their reception on the MF and LF bands.
-
The Pikes Peak Radio Amateur Association (PPRAA) serves as an ARRL Special Service Club, providing a calendar of events and activities for its members and the wider amateur radio community. The resource details upcoming events such as the USS Pueblo Memorial Museum Ships Weekend activations, a Cubical Quad Antenna Workshop, LARCFest, and various hamfests including Dayton Hamvention and Duke City Hamfest. It also lists on-air activities like a FreeDV digital voice mode event on 10 meters, a Black Friday Simplex Event on 2M and 70cm, and a 10m event for Technician class operators, emphasizing SSB privileges from 28.300 to 28.500 MHz. The PPRAA's event schedule includes educational opportunities like a Technician Class and a Soldering Workshop, alongside social gatherings such as the PPRAA Picnic and Car Show. Past event summaries highlight successful activities like the 2024 Megafest Raffle, Winter Field Day, and multiple fox hunts utilizing frequencies like 147.420, 147.480, and 147.540 MHz. The club actively supports POTA activations, exemplified by their AF0S park activation at Cheyenne Mountain State Park, and participates in historical commemorations like the USS Pueblo Memorial operations, demonstrating a broad engagement across various amateur radio facets.
-
Learn how an experienced ham radio operator rebuilt his trap dipole antenna for 30, 40, and 80 meters after a storm damage. Discover the process of upgrading to a short trap dipole for 40, 80, and 160 meters using double-wound traps made from RG-58 coax. Follow along for construction details and tips on building this unique classi.
-
This loop antenna is intended to be connected as an antenna for receivers that do not have a built-in antenna such as an HF set or an old tube radio. This square barrel is wound on a wooden frame. It consists of two windings that are galvanically isolated from each other, a main and a coupling winding. The diameter is about 40 cm.
-
A custom center hub for a Spiderbeam yagi antenna, enabling side-mounting on an existing mast. Challenges included structural instability, limited reach for assembly, and interference with a pre-mounted Spiderpole. A new hub using 40x40mm aluminum tubing provided strength, allowed side assembly, and supported fiberglass pole guy lines. The solution facilitated efficient installation and removal, delivering excellent performance compared to a SteppIR yagi.
-
FT-240 toroids measurements. The data was measured using well-calibrated HP instrumentation. All plots have been adjusted to a frequency range of 1-100 MHz on the horizontal axis and a resistance/impedance range of 10-1,000 ohms on the vertical axis. This adjustment facilitates comparison among different materials and aids in determining their suitability for use on the HF ham bands.
-
The POCKET TUNER V1.1 is a highly compact HF T-Match antenna tuner designed for QRPp and QRP portable operations. With a credit card-sized form factor, it is tailored for low-power setups, supporting HF bands from 10m to 40m. The tuner features a unique design using rotary switches for precise capacitor adjustments, allowing tuning in small increments. Its inductance selection is optimized for various bands, ensuring efficient performance. Equipped with a resistive tuning indicator, it protects the transmitter by reducing SWR during adjustments. This versatile and portable tuner is ideal for field operations, enabling efficient antenna matching for low-power rigs.
-
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.
-
The tri-band trapped delta loop antenna design operates on 80 meters (3.5–4 MHz), 40 meters (7–7.3 MHz), and 30 meters (10.1–10.15 MHz) using a single triangular wire loop. This configuration eliminates the need for an external antenna tuner or band-switching relays. The antenna's physical perimeter, approximately 270 feet, establishes 80M as the fundamental band, with specific trap placements enabling resonance on 40M and 30M. Trap design and placement are critical, with 30M traps positioned inboard of 40M traps within the horizontal element. Each slant leg measures approximately 80 feet. The resource references foundational information from the _ARRL Antenna Handbook_ and _ON4UN’s Low Band DXing_ regarding full-wave loop behavior and feedpoint impedances. The project aims to provide multi-band HF operation from a single, fixed antenna structure.
-
The DIY Power Meter project utilizes the _INA226_ high-side power monitoring chip, paired with an ATtiny85 microcontroller, to measure voltage, current, and power, displaying the results on a 128x32 OLED screen. The INA226 communicates via an I2C interface and is programmed with a calibration factor based on the shunt resistance and current register LSB. The project is designed to handle a maximum current of 500mA using a 0.16ohm shunt resistor, which can be adjusted to a 0.2ohm resistor, reducing the full-scale current range to 409mA with a resolution of **12.5uA**. The shunt resistor dissipates only 33mW at maximum current, making 1/4 watt resistors suitable for the setup. The PowerMeter.ino sketch configures the shunt resistance and maximum design current, automatically calculating the calibration factor. The project can be prototyped on a breadboard using an Arduino Uno, employing the Wire library for INA226 and OLED communication, and the u8g2lib library for the OLED display. For the ATtiny85 version, the Adafruit-TinyWireM and Tiny4kOLED libraries are used. The power meter is independently powered by a 3V CR2032 cell, with power switching options including manual switches or DC switched jacks. The low-side n-channel MOSFET switch configuration is tested but introduces voltage drop issues, making manual switching a more reliable option until a suitable DC switched jack is found. DXZone Technical Profile: INA226 | ATtiny85 | OLED Display | Power Meter
-
This **PDF report** documents a _maritime mobile_ DXpedition operating from the _Southern Ocean_ near Antarctica, detailing antenna deployment strategies on a sailing vessel. It addresses power management systems for remote operations and propagation characteristics specific to polar regions on **20m and 40m** bands. Operational strategies include managing high-density pileups using split frequency operation and maintaining signal integrity during periods of high aurora activity. Equipment considerations cover specific transceiver models like the Icom IC-7300, antenna types optimized for marine vessel installation, and battery power systems for extended periods without shore power. The resource also examines the use of satellite communication for real-time log uploads and QSL confirmation from remote locations, and discusses mitigating signal degradation from ice accumulation on antennas. DXZone Focus: PDF report | Maritime Mobile DXpedition | Polar Propagation | Split Frequency Operation
-
This page provides information on how to design an Off-Center-Fed Dipole (OCFD) antenna, suitable for amateur HF bands like 80 meters or 40 meters. The antenna design allows for VSWR minima on multiple bands, making it a good choice for multi-band use. Learn how to create an OCFD antenna in either flat-top or inverted-Vee form using a single support. The page also offers tools to generate radiation patterns, VSWR charts, and antenna current diagrams for your specific antenna design, helping hams understand performance factors. Ideal for ham radio operators looking to build their own effective antennas.
-
Presents DJ5IL's personal amateur radio station, detailing his journey as a licensed operator since 1973. The resource covers his **shack setup**, including an Elecraft K4D, Icom IC-7610, and various vintage transceivers like the Drake 2-B, along with a SPE Expert 1K-FA amplifier. Antenna systems include a PRO.SIS.TEL RD1524T rotary dipole for 40/20/15/10m at 15m height, an 18m vertical dipole with an SGC SG-230 tuner for 3.5-30 MHz, and an inverted-V dipole for 80m. The site features a **QSL gallery** showcasing his custom card designs and outlines his QSL policy, emphasizing the exchange of unique, personalized cards over generic confirmations. It also includes a detailed operator's biography, tracing his early fascination with radio, obtaining his license at 16, and memorable QSOs, such as a contact with his blood-relative W3NZ. The resource also delves into the historical significance of amateur radio's role in pioneering shortwave communication following the 1912 International Radiotelegraph Convention, which initially relegated amateurs to wavelengths of 200 meters and shorter. DJ5IL's philosophy on "ham spirit" is discussed, stressing the unpolitical nature of amateur radio as a global fraternity.
-
This page discusses the construction and design of a shortened 2-element Yagi antenna for the 40-meter band, focusing on the driven element. The author shares insights on adding hats to the coil to reduce losses and improve performance. The article also mentions the use of EZNEC modeling software and an AIM4170 analyzer for tuning. Amateur radio operators interested in such antenna design and optimization for the 40-meter band can find useful information and practical tips on this page.
-
The ICOM IC-705, a popular QRP transceiver for portable operations, often presents unique challenges for field deployment. This resource details practical solutions for common portable setup issues, particularly for _Parks on the Air_ (POTA) activations. It describes a custom bracket for connecting antennas to the IC-705 through a backpack's antenna flap, utilizing a BNC female-to-female chassis mount connector to mitigate cable tangles. The author shares experiences with a DIY magnetic loop antenna, noting its ease of tuning with the IC-705 and successful CW contacts on 40 and 20 meters over distances exceeding **1000 miles**. Another modification presented is a strain relief solution for the microphone cord, replacing the standard spring clip with an easier-to-attach method. The page also mentions using a _Wolf River Parks antenna_ for POTA activations and references the QRPGuys DS-1 antenna as another portable option. Firmware updates and integration with an LDG Z11-Pro II auto-tuner are also discussed.
-
Detecting stray RF voltages on station grounds, chassis, and interconnecting cables is crucial for preventing program and hardware failures in the shack. This article details the construction and application of an LED RF V-probe, which offers significantly higher sensitivity compared to conventional neon lamp indicators. The probe leverages two specific properties of modern red LEDs: their ability to glow at microampere currents and their rectification capability at frequencies up to tens of megahertz. The design features a simple circuit with two LEDs, allowing for indication of both positive and negative RF voltage half-waves. The minimum detectable RF voltage is approximately 2 V, a substantial improvement over the 40-60 V threshold of neon bulbs. The resource illustrates the probe's physical construction on a PCB and provides a direct comparison demonstrating its superior sensitivity in detecting RF fields near a coil. Two operational modes are described: a non-contact mode for high RF voltages (above 15-20 V) and a direct-contact mode for measuring lower RF voltages, with a safety caution for the latter. Practical examples show the probe's use in analyzing RF voltage distribution across a radio station setup at 1.84 MHz and 24.9 MHz, revealing insights into common-mode current issues and the effectiveness of mitigation strategies like adding radials.
-
This page details the construction project of the 'Stone', a QRP double conversion superhet SSB transceiver for the 40m band. The project is based on a kit from Tim Walford, G3PCJ, and includes step-by-step instructions for building and testing each stage. The author has added enhancements such as a three digit frequency counter and an automatic gain control. The content is aimed at hams interested in DIY transceiver construction and includes technical details of the build process.
-
This page contains detailed notes on repairing and aligning the Kenwood TS-440S HF radio. The author shares their experience repairing several TS-440S radios, highlighting common issues and repair techniques. The page also discusses parts availability, modifications, and the radio's performance for digital modes like FT8 and JT65. Aimed at ham radio operators interested in repairing and maintaining vintage HF radios, this page provides valuable insights and tips for working on the Kenwood TS-440S.
-
KISS703 is a 703 Hz narrowband digital mode for amateur radio, designed for simple, low-power operation without computers. A 500 Hz pilot tone ensures frequency alignment, replaced by unique tones for 37 symbols (letters, numbers, space). Built from common discrete components, it draws about 40 mA at 12 V, ideal for SOTA/IOTA use. The receiver uses amplification, wave shaping, and a pulse-counting frequency meter for manual decoding via a calibrated meter. Transmitter and receiver calibration involves marking meter positions for each tone, enabling fully self-contained messaging with minimal hardware in portable or fixed operations.
-
A versatile digital VFO design utilizing the Silicon Labs Si5351a oscillator chip and Nokia 5110/3310 graphics LCD display, operating from 1-160MHz with dual VFO capability. This microcontroller-based system, powered by an ATmega328 processor, features rotary encoder tuning, selectable step sizes, RIT control, and comprehensive band memory functions. Drawing less than 40mA at 3.3V, it significantly improves upon previous DDS designs' power consumption while offering advanced features like S-meter display, VFO lock, and programmable BFO/CIO offsets. The design achieves flexible functionality through simple hardware implementation and efficient software architecture, making it particularly suitable for QRP and portable amateur radio applications.