Search results

MMTTY V1.70K, released June 4, 2017, provides a full 3.5MB installation for RTTY operations on Windows platforms including XP, Vista, and Win7. The software, developed by JE3HHT, utilizes a soundcard for RTTY decoding and encoding, with support for external FSK keying via parallel or serial ports, including USB serial adapters. An MMTTY Engine V1.70K is also available, specifically designed for integration into other commercial amateur radio programs requiring RTTY functionality. Older versions such as MMTTY V1.68A (September 29, 2010) and MMTTY V1.66G are accessible, alongside a non-installer version (MMTTY168A-i.zip) for experienced users. The resource includes an updated ARRL.DX file for callsign lookup and offers a comprehensive 18MB PDF help file for offline viewing or download. Support for the software is directed to a group.io community. MMTTY integrates with **COMFSK** and **EXTFSK/EXTFSK64** for precise FSK keying, enabling direct radio control. The site also hosts MMJARTS V1.03, a 254KB utility released September 6, 2002, which generates log and summary sheets specifically for the JARTS RTTY contest, linking to the official JARTS website for contest information.

This project details three variants of a vertical half-wave antenna design for the 4-meter (70MHz) amateur radio band. The antennas use end-feeding with a parallel-tuned circuit for impedance matching to 50-ohm coaxial cable. The first variant uses suspended flexible wire for portable use, the second employs a fiberglass rod with internal wire for permanent outdoor installation, and the third utilizes aluminum tent poles for quick mobile deployment. Despite the narrow bandwidth of the matching circuit, this suits the narrow 4m FM allocation well. The design offers an effective omnidirectional radiation pattern and can be constructed with readily available materials.

gMFSK, a Gnome Multimode HF Terminal, provides a comprehensive software solution for digital conversational modes on HF bands within Linux and Unix-like operating systems. The application facilitates sending and receiving various digital modes, including MFSK (MFSK16 and MFSK8), RTTY, THROB (1, 2, and 4 throbs/sec), PSK31 (BPSK and QPSK), PSK63, and MT63. It leverages the computer's soundcard for transceiver interfacing, performing all digital signal processing on the main CPU. The software features a multimode waterfall display incorporating waterfall, spectrum, and scope views, enabling _point-and-click tuning_ of decoded signals. Remote logging capabilities are supported via SysV IPC, with integration for logging applications like Xlog. PTT control is managed through serial or parallel port lines, and rig control is implemented using the _Hamlib_ library, allowing for real-time frequency display and transceiver manipulation. Fixtext macros can incorporate variables and command-line output. Distributed under the GNU General Public Licence, version 2, gMFSK requires Gnome libraries and FFTW 2.x libraries for operation, even without a full Gnome desktop environment. The software's design ensures compatibility with any soundcard supported by the operating system.

End-Fed Half-Wave Antennas (EFHWAs) are analyzed for their utility in portable QRP operations, emphasizing their simplicity, efficiency, and predictable radiation patterns compared to other portable antenna types. The discussion contrasts EFHWAs with vertical antennas, random length wires, and center-fed dipoles, highlighting the common pitfalls of each, such as ground system dependency for verticals and feedline issues for dipoles. The article details the electrical half-wavelength calculation using the formula L (Ft) = 468/F(MHz) and explains how EFHWAs can be resonant on harmonic frequencies, enabling multiband operation. Various deployment configurations are presented, including the inverted L, inverted Vee, sloping wire, and vertical setups, each with specific advantages for radiation angle and polarization. For instance, a vertical EFHWA offers a low angle of radiation suitable for DX contacts without requiring an extensive ground system. The resource also addresses the counterpoise requirements, suggesting a quarter-wavelength wire or connection to a metallic structure for decoupling. A schematic diagram for a simple parallel-tuned circuit tuner, based on the _Rainbow Bridge/Tuner_ design, is provided, detailing component values for 30 and 40 meters, including a 6 microhenry toroidal inductor and a 20-100 picofarad mica compression capacitor. The tuner's adjustment process for SWR matching is also outlined.

Operating amateur radio satellites effectively requires precise knowledge of their orbital mechanics and pass times. Gpredict, a real-time satellite tracking and orbit prediction application, addresses this need by allowing operators to monitor numerous satellites simultaneously. It displays critical data such as position and pass details through various visualizations, including lists, tables, maps, and _polar plots_. Unlike many other satellite tracking programs, Gpredict introduces the concept of visualization modules. These modules enable users to group satellites and configure each group independently, offering unparalleled flexibility in how orbital data is presented. This modular approach supports tracking satellites from multiple observer locations concurrently, which is particularly useful for stations with diverse antenna setups or remote operations. Originally a GUI client for John Magliacane's _Predict_ program, Gpredict evolved to integrate its own tracking code for improved performance. The software is distributed under the GNU General Public License, ensuring it remains free and modifiable for the amateur radio community.

MultiKeyer is a dedicated computer keying program designed for amateur radio operators engaging in specialized operating activities such as Earth-Moon-Earth (EME) and Meteor Scatter, as well as general contest operations. It provides distinct modes for both CW and Phone transmissions, enabling automated message sequencing and playback of pre-recorded audio files. The software's interface shares a similar "look and feel" to the popular WSJT Meteor Scatter/EME program, facilitating ease of use for operators familiar with that platform. For CW operations, MultiKeyer offers an EME Auto mode for sending timed messages crucial for EME and Meteor Scatter, alongside a Contest mode that handles automatic CQ calls and preprogrammed messages. On the Phone side, it features a Sequenced Phone mode for transmitting prerecorded .wav files during Meteor Scatter events and an Auto Phone mode for contest use. The program leverages serial COM ports for CW and PTT signaling, and the soundcard for .wav file playback, with configurable PTT interrupt options. MultiKeyer integrates with TRX-Manager for PTT and CW keying, and can send callsigns for logging. It also supports WSJT-style "callsign.txt" files for lookups and adheres to the SO2R protocol for parallel port connections. Designed for Windows 98 and NT, it generally functions on Windows 95, ME, XP, and 2000, requiring a 133 MHz Pentium-class processor.

HAMIC, is a program designed to simplify a number of calculations commonly used by HAMs. It is designed for the HAM radio hobbyist, but may be useful to others as well. HAMIC has a simple to use, but powerful graphical interface that allows solving simple circuits such as resistors in series or parallel, or more complex circuits such as L networks or T networks. As well, other calculations such as SWR and reactance conversions are supported. Windows shareware.

An easy to deploy antenna, commonly considered the best solution for portable operations. Thir article includes a simple LC parallel circuit to match the impedance by IW7EHC

EXTFSK.DLL is an MMTTY extension that interfaces MMTTY to a user-made hardware device via serial port, parallel port or USB

zLog for Windows is a freeware full-featured contest logging software that runs on Windows. It supports major international and domestic (JA) contests and is customizable to many other contests not directly supported by zLog. Features include CW keying via parallel/serial/USB interfaces, highly sophisticated TCP/IP network that allows instant synchronization of a log of an M/M station, rig control, PacketCluster connenction. By JJ1MED/AD6AJ

The _Sci.Electronics FAQ: Repair: RFI/EMI Info_ document, authored by Daniel 9V1ZV, provides a detailed analysis of computer-generated RFI/EMI, focusing on its impact on radio reception. It identifies common RFI sources such as CPU clock rates (e.g., 4.77 MHz to 80 MHz), video card oscillators (e.g., 14.316 MHz), and even keyboard microprocessors, all of which generate square-wave harmonics across HF and L-VHF regions. The resource outlines a systematic procedure for pinpointing RFI origins, including disconnecting peripherals and using a portable AM/SW receiver with a ferrite rod antenna to localize strong interference sources. The document categorizes RFI mitigation into shielding, filtering, and design problems, offering practical solutions for each. It recommends applying conductive sprays like _EMI-LAC_ or _EMV-LACK_ to plastic casings of radios, monitors, and CPUs to create effective Faraday cages, emphasizing proper grounding and avoiding short circuits. For filtering, the guide suggests using line filters, ferrite beads, and toroids on power and data lines, and small value capacitors (e.g., 0.01 uF for serial/parallel, 100 pF for video) to shunt RFI to ground. It also discusses the use of bandpass, high-pass, low-pass, and notch filters on the receiver front-end or antenna feed to combat specific in-band noise.

The dipole shown in this document is installed in an inverted Vee configuration, with two leg elements on each side held parallel to each other by 21cm spacers. The upper leg is for 40m and the lower leg for 20m. The spacers are made of 7mm plastic garden hose support for garden sprayers cut to 21cm.

Mobile RFI, often manifesting as persistent noise in the receiver even with the antenna disconnected, frequently originates from the vehicle's power supply system. This guide details systematic troubleshooting steps, beginning with isolating the radio from the car's 12-volt supply to confirm the power system as the noise source. It emphasizes the critical importance of drawing power directly from the battery using **heavy gauge wire**, bypassing the fuse block to leverage the battery's natural capacitance for RFI suppression and ensuring a solid RF ground. Proper routing of power lines through the firewall is also covered, advocating for dedicated grommeted holes to prevent inductive coupling from other wiring harnesses. The article stresses the necessity of fusing both positive and negative leads from the battery, a crucial safety measure to prevent damage to the rig and mitigate high-current risks should the battery's engine block ground become compromised during service. Addressing **alternator whine**, a common high-pitched noise that varies with engine speed, the resource suggests checking battery connections and the alternator-to-battery harness for looseness or corrosion. It also mentions the utility of adding an external RF noise suppression capacitor in parallel with the alternator's internal capacitor for enhanced filtering, and the effectiveness of commercially available in-line power supply filters.

A portable wire antenna for the HF bands, made with a common speaker wire. In its natural form, the speaker wire acts as parallel feed line coming up to the bottom of the PVC feed point. From there, it's split into two wires, one heading out each side of the PVC tee.

The resource, "Conventional Use of Transmission Line," meticulously details the operational principles of transmission lines, emphasizing the Transverse Electromagnetic (TEM) mode of energy transfer. It clarifies that for a line to function purely as a transmission line, all currents must be confined internally, with external fields ideally zero. The discussion differentiates between balanced and unbalanced lines, asserting that while both require equal and opposite currents within the conductors, the key distinction lies in the voltage relationship of each conductor to the surrounding environment. It highlights that a good antenna pattern does not inherently confirm proper feeder balance, and that common-mode currents can lead to RF in the shack and increased noise levels, even without pattern distortion. The article further explains that a transmission line can become a radiating conductor if energy is applied in a non-TEM mode, leading to common-mode issues. It cites classic texts like Jordan and Balmain's "_Electromagnetic Waves and Radiating Systems_" and Kraus's "_Antennas_" to support its definitions of TEM mode operation. The content also explores non-transmission line applications of parallel or concentric conductors, such as _coaxial dipoles_ and _folded dipoles_, which intentionally operate in non-TEM modes for antenna functionality. The author, _W8JI_, stresses that simply measuring equal currents is insufficient to confirm a balanced feeder; phase and voltage balance to ground are equally critical.

A 60-foot available space, for example, might necessitate a shortened multiband dipole array to cover 80, 40, and 15 meters effectively. This resource details the construction of such an antenna, combining full-size and coil-loaded dipoles on a single feedline. It addresses the common challenge of fitting multiple HF bands into restricted physical footprints, providing practical guidance for hams with smaller backyards or portable operations. The core of the offering is an interactive calculator that determines required loading coil inductance and dipole lengths for various amateur bands from 160m to 10m. Users input their available space, and the tool provides dimensions, coil turns, and an efficiency rating (Good or Fair) based on the antenna's electrical length relative to a quarter-wavelength. It also suggests suitable _PVC_ pipe diameters for coil forms. The article further illustrates a center feed-point assembly using an 18-inch section of 2-inch _PVC_ pipe, detailing eye-bolt spacing and coaxial connector installation. It emphasizes the importance of adequate spacing between parallel dipoles and offers customization options for the feed-point, including the addition of a _Balun_ for improved feedline isolation.

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.

Four _Headway 38120_ LiFePO4 cells form the core of an 8AH 12V battery pack, designed for reliable emergency and field power in amateur radio operations. These batteries offer significant advantages over traditional lead-acid types, including a lifespan up to **10x** longer in charge/discharge cycles, lower internal resistance for faster recharging, and a flatter discharge curve that maintains voltage stability during use. Their inherent safety, being a flame-retardant technology, makes them a preferred choice for portable applications. Proper configuration, including parallel/serial setups, and careful charging/discharging protocols are crucial for maximizing battery life. Each cell has a nominal voltage of 3.2 volts, with a maximum charge voltage of 3.65 volts. A Battery Management System (BMS) is highly recommended to prevent overcharging or deep discharging, safeguarding the cells. The project emphasizes safety, noting the batteries' high short-circuit capacity of **200 AMPS** and the critical importance of incorporating an inline fuse between the battery pack and the load. Components like the battery holder, buss bars, and a suitable case are also detailed.

Fully functional weathervane conceals an efficient 2- meter base-station antenna. Your Neighbors and HOA won’t know it’s there and they will love the rooster-vane. The Rooster-Tenna is a covert 2-meter ham radio antenna disguised as a functional weathervane, ensuring seamless integration into residential environments. This improved version features a wide-spaced parallel-fed folded dipole in a compact skeleton slot design. Constructed from aluminum tubing and acrylic supports, it offers omnidirectional, vertically polarized performance suitable for repeater and satellite use. Easy to mount and tune, it achieves a low SWR across the 2m band. With 3D-printable parts available, the Rooster-Tenna blends practicality with stealth, making it an ideal solution for HOA-restricted areas