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The 222 MHz Transverter project, based on Zack Lau's (W1VT) original July 1993 QEX magazine design, provides an IF of 28 MHz for both transmit and receive paths. Rick Bandla (VE3CVG) contributed supplemental notes and construction details, including modifications to achieve 10 mW output power from an initial 4 mW PEP. The design incorporates three distinct boards: a Local Oscillator (LO), a Transmitter (Tx), and a Receiver (Rx), with an estimated parts cost of just over $150 CDN, significantly less than commercial kits. Construction involves both through-hole and surface-mount components, with specific guidance on mounting MAV and MAR devices, grounding techniques, and component selection. The project details include parts lists, schematics for the LO, Tx, and Rx, and board layouts. Troubleshooting advice emphasizes sequential testing, starting with the LO, then Tx, and finally Rx, using a 194 MHz and 222.100 MHz capable FM handheld for signal tracing. Further enhancements are discussed, such as an optional Tx driver stage to boost output to 100 mW and the potential modification of a Motorola Maxor 80 PA for 222 MHz SSB/CW operation. The resource also covers practical aspects like power attenuation pads for IF radios (e.g., FT817) and considerations for enclosure design, including repurposing a Maxor 80 case. Performance reports indicate successful 70 km contacts with only 4 mW output.

Initially planned as an article on the R-407 station mast, this project evolved into creating a custom mast kit. Utilizing original materials, the design was modified for cost-effectiveness and practicality in home assembly. The new mast extends to 10 meters, featuring secure connections, a leather-lined base to prevent metal-on-metal friction, and sturdy military-grade anchors. Modifications include lengthened connecting tubes, improved anti-rotation features, and a convenient base design for solo assembly. Ideal for amateur radio operators, this mast provides stability, ease of construction, and versatility, proving more economical than professional products without compromising on performance or reliability. Article in Czeck.

Collection of modifications for the Retevis RT3, a monoband handheld transceiver for DMR (digital voice) and analog FM. It is almost identical to the Tytera MD-380.

An attic wire antenna with several modifications during the time. Began as a simple coax fed doublet antenna, and upgraded to a multi-band hf fan dipole, till the G5RV all deployed in an attic.

After a storm damaged the antenna, W6AER replaced it with a pre-made capacitance hat from DX Engineering. Using hose clamps and conductive grease, he ensured durability. Experimenting with radials and a coil, he aimed for better performance and resilience.

This page by Lajos Hoss, HA8HL, provides a detailed guide on how to build a simple direct receiver using FT8QRP CAT control support. The author shares his experience in making QSOs with FT8, WSPR, and JT65 modes during the Covid-19 lockdown. Modifications to the VFO, transmitter design using BD329 transistor Class A amplifier, and the challenges faced in achieving clean output signals within legal limits. This project is interesting for those hams that are interested in experimenting with DIY transmitter projects and understanding CAT control support for various amateur radio modes.

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.

Discover how the author, KK4Z, has perfected his Frankentenna over the years for portable operations, especially for Parks on the Air (POTA). Learn about the components sourced from different companies like Buddipole and Chameleon, allowing for versatility as a vertical antenna, endfed with a counterpoise, or even a dipole. The article also covers specific tweaks and modifications made to enhance performance. Ideal for hams looking to optimize their portable station setup with a reliable and lightweight antenna solution.

This page discusses the purchase of a fiberglass push-up mast for portable operations in the ham radio hobby. The author shares their experience with the MaxGain Systems MK-4-HD mast, highlighting its versatility for both home and on-the-go setups. They also detail modifications made to the mast base and provide insights on tube sizes for different antenna types. The content is useful for hams looking to improve their portable station setup and optimize antenna performance in various environments.

The article discusses the use of SDR# (SDR SHARP) software for SDR receivers, highlighting its Band Plan feature that visually represents RF spectrum allocations. The author modified SDR# to display detailed IARU HF band plans, creating three XML files for different IARU regions. These files include various operational modes and specific frequency allocations. Despite potential errors, the modifications aim to enhance the usability of SDR# for ham radio operators. The article includes references and download links for the XML files and IARU band plans.

The UV-K5 HF Fullband receive firmware version 0.3 introduces enhanced SSB capabilities using the SI4732-A10 chip. Released separately from UV-K5 CEC firmware, it offers improved HF reception, mode changes, frequency fine-tuning, and user modifications. New PCB designs and detailed usage instructions are included.

Learn how to build your own RF signal generator for aligning radios by following the modifications made to the circuit of an existing project. Explore the use of a common cathode varactor diode and a single center-tapped 24 VAC transformer to simplify the design. Discover alternative components like the MACOM 4ST079CK-287T varactor diode, which offers cost-effective solutions compared to unobtainable options. Find inspiration in modifying existing projects and gaining practical knowledge in electronics. Purchase the Nuts and Volts magazine for detailed schematics and a deeper understanding of RF signal generators.

The FT101ZD DDS VFO project replaces the original VFO in the Yaesu FT101Z/ZD rigs with an AD9850 DDS module, providing enhanced frequency control. It uses the original optical encoder and clarifier for compatibility, with a custom 6V power supply modification. The project includes selectable step sizes, a frequency save function, and works with both RX and TX modes. The design involves mechanical and electronic modifications, including SMD components and a custom PIC processor. Calibration ensures accurate frequency output, with further improvements under consideration.

The ICOM IC-745 is a durable 1980s HF transceiver, ideal for enthusiasts who enjoy restoration. While lacking modern serial control, it supports digital modes with modifications like sound card connections and frequency stabilization. Enhancements like an RTL-SDR panadapter can also be added, making it a versatile and valuable radio for contemporary use.

VE1ZAC's analysis details the performance of **MFJ927** and **SGC239** autotuners with portable HF vertical antennas, specifically comparing 31 ft and 43 ft configurations. The resource originated from challenges encountered during a Maritime QSO Party roving operation, necessitating a lightweight and easily deployable antenna system. Target bands for the contest included 80, 40, 20, 15, and 10 meters, with a maximum power handling of 100 W CW. The author utilized a 30-foot carbon fiber push-up pole to support a vertical wire element, noting its 2 lb weight and reliability. EZNEC modeling was employed to predict performance, showing favorable results for a 30-foot vertical with elevated radials, particularly on 40 and 20 meters. Feedpoint impedance measurements, taken with an AIM4170C, are presented for various HF bands, both with and without a 41-foot RG6 stub designed to reduce reactance on 80 and 20 meters. The stub significantly improved matching on these bands, easing the tuner's workload. Operational tests revealed issues with the MFJ927's reliability during contest setup, leading to reliance on the K3's internal tuner. The SGC239, tested post-contest, performed flawlessly. A detailed side-by-side comparison covers mechanical aspects, connection options, power bias, impedance range, board quality, and documentation. Modifications to the MFJ927, including a new aluminum case, white paint for heat reduction, and upgraded impedance-measuring resistors, are also described.

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.

The page provides a collection of modifications and upgrades for the Kenwood TS440 transceiver. Hams looking to enhance the performance or features of their Kenwood TS440 will find valuable information and instructions here. The site offers a range of mods for various amateur radio equipment, catering to a global audience of radio enthusiasts. Visitors can easily navigate to other related pages on modifications for different radio models, as well as general information on CB and ham radios.

The Kenwood TS-440S operates across HF bands with a frequency range of 10 MHz to 30 MHz, featuring SSB, CW, and FM modes. It supports various modifications for improved performance, including circuit enhancements and software updates. Users can access detailed diagrams and troubleshooting guides to optimize their setup. The transceiver's architecture allows for easy integration with external devices, enhancing its versatility in the field. Practical applications include participation in DXing and contesting, where the TS-440S's capabilities can be fully utilized. Operators have reported significant improvements in signal clarity and reception after implementing recommended mods. Comparisons with other HF transceivers highlight the TS-440S's reliability and adaptability, making it a preferred choice among seasoned operators. Resources for power supplies, antennas, and additional accessories are also available, ensuring a comprehensive support system for users aiming to maximize their station's potential.

This post discusses the Norcal 2N2/XX CW transceiver kit and provides suggestions for minor mods and parts substitutions. The author shares their experience assembling the kit and highlights the simplicity and joy of operating a QRP CW transceiver. The post also includes images and a list of recommended modifications towards the end. If you own or are interested in acquiring a Norcal 2N2/XX kit, this post offers valuable insights and recommendations to enhance your experience as a ham radio operator.

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.

Learn how to eliminate RF interference from your Behringer HA400 headphone amplifier for a better listening experience. Discover the simple modifications needed to prevent distortion caused by RF in your audio setup. Follow the step-by-step instructions provided by WB5NHL Ham Radio to improve the performance of your headphone amplifier in ham radio activities.

This study analyzes the antenna pattern of the Utah Amateur Radio Club's 146.760 MHz repeater following antenna relocation in 1997. Noting degraded transmission toward the north, a customized signal mapping system using a Yaesu FT-817, GPS, and software was developed to log real-time signal data. Calibration techniques extended the radio's signal range, enabling precise field measurements. The method allowed continuous signal strength monitoring while driving, revealing anomalies in coverage likely due to tower modifications. Findings helped assess and visualize the antenna’s actual radiation pattern and highlighted environmental impact on signal distribution.

An Arduino-based interface provides a remote tuner call command for Icom **IC7700** and **IC7800** transceivers, addressing the lack of a built-in function for external tuners such as the MFJ 998RT. This setup initiates a low-power transmit signal, typically 15 watts, allowing the remote autotuner to perform its matching sequence. The article details the required CI-V line communication and modifications to existing Arduino code, specifically referencing contributions from Jean-Jacques ON7EQ for improved Icom interrogation routines. The system involves a sequence of steps: storing the transceiver's current mode and power, disabling the internal autotuner, activating a control relay to interrupt the amplifier line, switching to RTTY mode at low power, and initiating transmit. The transmit duration is manually controlled by the operator, observing the SWR meter until a low SWR is achieved, then a second button press stops the transmission. A built-in 4-second transmit limit provides a safety measure. After tuning, the routine restores the original mode and power settings, re-enables the internal autotuner, and performs a brief 2-second RTTY transmission for internal tuner adjustment. The circuit diagram includes a Panasonic form 2 relay for amp control and emphasizes critical delays in the Arduino code for stable operation at 9600 baud CI-V communication. Compatibility with logging software like DXLab, N1MM, and N3FJP is noted, with specific interrogation time settings required to avoid conflicts.

This resource details **cooling modifications** for Ameritron AL82, AL1200, and AL1500 HF amplifiers, specifically addressing heat issues encountered during high-duty-cycle digital mode operation. The author, WD4NGB, observed excessive heat in the tank area and band switch on an AL82, attributing it to insufficient exhaust over the 3-500 tubes and a complete lack of exhaust over the tank area. The modifications aim to prevent common failures such as damaged band switches and deformed insulating materials by increasing airflow and exhaust area. The page describes adding five holes to the chassis for enhanced cooling to the band switch and tank area, alongside enlarging the exhaust area over the inner 3-500 tube and the tank area on the amplifier cover, utilizing expanded metal for safety and RF shielding. The original cover featured 26.25 square inches of exhaust; the modified version significantly increases this to 48.5 square inches over the tubes and introduces an additional 15 square inches over the band switch. These changes are intended to resolve heating problems encountered during heavy, 100% duty cycle use in modes like RTTY or long SSB contests, which typically generate substantial heat. The article also discusses upgrading to a higher output fan, such as the G2E085-AA05-21, and modifying tube sockets for improved airflow and reduced back pressure, citing Tom Rauch (W8JI) of CTR Engineering as a source for parts.

Demonstrates the construction of 'The Virgin', a **direct-conversion receiver** specifically designed for the 40m amateur radio band. This project, completed in February 2016, features a fixed operating frequency determined by a crystal oscillator, requiring a physical crystal change to alter the reception frequency. The design incorporates two integrated circuits and a power regulator, emphasizing simplicity with a single control knob. The author details the initial design, subsequent modifications to the front end, and troubleshooting steps addressing common issues like audio motorboating and power supply instability. The resource presents the final design of the receiver, reflecting the author's first experience building such a unit between December 2015 and February 2016. It offers practical insights into basic circuit construction and the iterative process of refining a homebrew radio project. The content is particularly relevant for those interested in fundamental receiver principles and hands-on **QRP** transceiver building.

This page describes a project involving repurposing the Weathalert receiver for controlling a radio club's beacon system remotely. The author details the modifications made to the receiver, including changing the crystal frequency and adding a DTMF decode chip and PIC for remote control. The project aims to enable the turning off of beacons to prevent interference, with plans to control each beacon and the Packet Radio digi. The article provides insights into the technical aspects of modifying the receiver and showcases the author's experimentation with different crystals for optimal performance.