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This antenna is fed for vertical polarisation, to give a low angle of radiation for DX and also a nearly omni-directional radiation pattern.

A Mississippi Style 40 meter magnetic loop made from available aluminum conduit, this antenna will not disappoint by Ken Holland, K9FV

A 144 MHz kilowatt amplifier project details the construction and performance of a high-power VHF linear using the GU74b tetrode. This Russian tube, equivalent to the Svetlana 4CX800, is noted for its conservative datasheet ratings, performing closer to 800-1000W anode dissipation in practical applications. The design prioritizes compactness and achieves 1.2 kW output with only 20W of drive power, demonstrating a 70% efficiency at 2.5 kV plate voltage. The amplifier has been successfully deployed in demanding _EME_ (Earth-Moon-Earth) operations since June 1994. Challenges encountered during development included achieving stability with a grid-1 input configuration. The author, _CT1DMK_, opted not to publish the full design due to its complexity, suggesting it might be difficult for less experienced builders to replicate successfully. However, he invites direct contact for those with specific interest in the design. Future plans include a "144MHz GS35b compact amplifier" project, promising another kilowatt-plus design. This resource offers insights into high-power VHF amplifier construction and the practical application of specific power tubes.

This project shows how to build a 50-ohm dummy load using non-inductive resistors, oil for heat dissipation, and a simple assembly process. It enables accurate transmitter tuning, testing, and power measurement across LF to UHF bands. The setup allows meter calibration by measuring peak voltage, applying diode drop correction, and calculating RMS voltage and power precisely. Parts are inexpensive and widely available. With proper assembly, this dummy load offers extended service life, accurate readings within 2%, and a reliable alternative to costly commercial wattmeters for amateur radio applications.

PA3FWM's software defined radio (SDR) page documents his extensive hardware and software development efforts between 2004 and 2009. Initial experiments utilized a direct conversion receiver with 90-degree phase difference, feeding a PC soundcard at 48 kHz sample rate, covering 24 kHz of spectrum around a 7080.5 kHz local oscillator. This setup, similar to AC50G's QEX 2002 article, allowed for basic I/Q signal processing to distinguish signals above and below the LO frequency. Limitations included fixed crystal frequencies, 16-bit dynamic range, and narrow bandwidth. Subsequent hardware iterations aimed for enhanced performance, incorporating external 24-bit ADCs with 192 kHz sample rates, connected via 10 Mbit/s Ethernet. A **MC145170-based PLL** and programmable octave divider provided a 58 kHz to 30 MHz tuning range. The **Tayloe mixer** was employed, with differential outputs feeding a PCM1804 ADC. An ATmega32 microcontroller handled serial data conversion to Ethernet frames, though without CRC calculation due to processing constraints. Later designs integrated AD7760 2.5 Msamples/second ADCs and a Xilinx Spartan-3 FPGA, enabling direct reception of 0-1 MHz spectrum and eventually 2.5 MHz bandwidth across the shortwave spectrum. Software was refactored to use an initial 8192 non-windowed FFT for efficient high-bandwidth processing. The project culminated in a two-way QSO on 21 MHz using the developed hardware and software, demonstrating transmit capabilities with a D/A converter. The system exhibited a 2.5 MHz wide spectrum display and a zoomed 19 kHz display, capturing signals like ionospheric chirp sounders and RTTY contest activity. Challenges included noise leakage from digital circuitry and cooling for high-power dissipation components.

Welcome to the official Home Page of SouthEastern Repeater Association Inc. SERA is the largest Amatuer Radio Coordination organization in the United States. SERA represents Kentucky, Mississippi, North Carolina, South Carolina, Virginia, Tennessee, West Virginia and Georgia

Ameritron Al-811H Tuning for Power/Dissipation/Linearity, and More Generally 811A Tube Amps in Grounded Grid

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.

QST review for Yaesu FT-920

A handy piece of test equipment useful for HF bands, can absorb a 200W modulated carrier for almost 2 minutes. It is housed in a tin and part filled with dry sand that helps in power dissipation

This Power meter is capable of dissipating up to 100 watts for a short period and 20 watts continuously

Designer and supplier of tower reinforcement systems to the wireless industry.

Mississippi's Premiere DX Organization

The Alcorn County ARES group provides crucial **emergency communications** support within Alcorn County, Mississippi, operating under the Amateur Radio Emergency Service framework. This organization mobilizes licensed amateur radio operators to assist public safety agencies during emergencies, natural disasters, and other critical events when conventional communication infrastructure fails or becomes overloaded. Their activities include regular training exercises, participation in local drills, and maintaining readiness to deploy communication assets. Members engage in various aspects of amateur radio, including voice, digital modes, and message handling, ensuring a robust and redundant communication network. The group's focus on preparedness and community service aligns with the core principles of ARES, emphasizing rapid response and effective information relay during crises. They often collaborate with local emergency management agencies, such as the Alcorn County Emergency Management Agency, to integrate amateur radio capabilities into broader disaster response plans. Dustin Brumfield, KD5LAP, serves as the Public Information Officer, facilitating outreach and coordination. The club's operational area is specifically Alcorn County, Mississippi, contributing to local resilience.

The Mississippi QSO Party, sponsored by the Mississippi Section of the ARRL, offers a prime opportunity for hams worldwide to make contact with Mississippi stations. This annual event encourages both in-state and out-of-state operators to activate Mississippi counties, promoting activity across the Magnolia State's diverse geographic regions. Participants often operate from various locations, including parks and historical sites, contributing to the unique character of the contacts. Operators typically utilize a mix of HF and VHF bands, employing CW, SSB, and digital modes to maximize their QSO count and multiplier acquisition. The exchange usually involves a signal report and county for Mississippi stations, or state/province/country for others. Results are compiled and published, recognizing top scorers in various categories and encouraging friendly competition among participants. The event serves as a significant annual gathering point for the Mississippi amateur radio community, fostering camaraderie and operational skill development.

Examples of absorbtive low-pass filters in which the unwanted high-frequency energy is separated from the wanted output and then dissipated in matched resistors

F5NPV explores the construction of a cost-effective 1KW dummy load for radio enthusiasts. Purchasing a commercial dummy load can be expensive, but with basic materials such as a metal can, resistors, mineral oil, and a heat dissipator, you can build your own. The article provides a simple guide to assembling the load, including the importance of testing for inductance. The DIY dummy load yields impressive performance, with an SWR of 1.2:1 across multiple bands and the ability to handle up to 1KW of power. This budget-friendly solution is a valuable addition to any radio shack.

SERA Mississippi

Magnolia Amateur Radio Club serves the Starkville area in North Mississippi.

A 40 dB tap attenuator taht need only dissipate 2.3 watts, while delivering the same 0.02 watts to the input sensor.

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

Twenty 1-watt carbon film resistors are configured in parallel to construct a 50-ohm **dummy load** for amateur radio applications. The design incorporates a heatsink for thermal dissipation and an **SO-239 connector** for RF input, making it suitable for QRP operations. This budget-friendly project details component selection, soldering techniques, and mounting procedures, achieving a continuous power rating of 10 watts and intermittent handling of up to 100 watts across HF and VHF frequency ranges. The resource provides a step-by-step guide for assembly. This construction offers an economical solution for essential shack tasks such as antenna tuning, transmitter testing, and SWR meter calibration without radiating an RF signal. The utilization of readily available components significantly reduces the overall build cost compared to commercial alternatives, providing radio amateurs with a functional and reliable test accessory. While specific VSWR measurements are not provided, the design prioritizes practical utility for low-power transceiver diagnostics and general RF experimentation.

We are a non-profit amateur ham radio association located in the rural Lakes Region of New Hampshire. We actively promote 2 way radio, also known as ham radio. Our members are friendly and knowledgeable. If you are a first time visitor and are curious about this great hobby, we provide testing for ham licenses, have fun get-togethers, and are ARES affiliated for emergency communications. We also are home to 6 repeaters. Three are located on Bennett Hill in Ossipee, one on Mt. Rowe in Gilford and two on New Durham Ridge, New Hampshire.