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The article describes a high-gain, compact beam antenna design for the 2-meter band (144-146 MHz). The NSH 4x4 Boomer is a 4-element antenna that is mounted on a 4-foot boom with an 8.2 dB gain, 1.2:1 SWR, and a front-to-back ratio of 18 db. It is designed for mobile operations and little area, making it perfect for field usage such as disaster management. The design employs regularly spaced parts with a straightforward gamma match for tuning, and the construction materials include a square boom and polished aluminum tubes. In local and portable tests, the antenna worked regularly, achieving contact distances of up to 15 kilometers.

Details the construction of a Copper Cactus Dual-Band Super J-Pole Antenna, providing specific measurements for 1/2-inch copper tubing sections, including a 57-1/2-inch long section and a 19-inch short section, along with a 42-inch piece of 3/16-inch or 1/4-inch soft copper tubing for the matching stub. It covers soldering techniques for copper fittings, drilling an SO-239 panel mount coaxial fitting, and securing feed point connections with stainless steel adjustable band clamps. The resource specifies materials such as Schedule M 1/2-inch copper tubing, various copper fittings, a hardwood dowel or Fiberglas rod for insulation, and #14 stranded copper wire for the feed point. The guide simplifies the J-pole feed point by using an SO-239 fitting with an elongated mounting hole and band clamps, noting an optimal feed point distance of approximately 3 inches above the crossbar for proper impedance matching. It recommends a 4-turn coax choke, 5 inches in diameter, placed within 3 to 4 inches of the feed point for 2-meter operation to mitigate RF on the feedline. The project emphasizes weather sealing with silicon or butyl rubber compound and clear lacquer for durability and appearance.

A 5/8-wavelength vertical antenna for 2-meter FM operation is detailed, focusing on eliminating loading coils by utilizing a series inductor to cancel capacitive reactance at the feed point, thereby presenting a 50-ohm impedance match. The design illustrates three basic configurations, including a method employing a short-circuited coaxial stub for inductance, as implemented by K4LPQ. An alternative design is presented where the center conductor of the stub is extended one-quarter wavelength, creating a signal-frequency short and allowing for an insulated wire stub to develop the required series inductance. The article provides electrical theory and mechanical considerations for building the antenna, emphasizing the adjustment of stub length for proper impedance matching. This technical documentation is intended for amateur radio operators interested in homebrewing VHF antennas, offering practical insights into impedance matching techniques for vertical radiators.

When new to the 2-meter FM transceiver, securing a quiet frequency for chatter seems straightforward, but it's essential to navigate FCC rules and band plans effectively. Even though frequency allocations are consistent above 50 MHz for Technician licenses, adherence to specific segments within the 2m band—ranging from 144 MHz to 148 MHz—is crucial. This includes respecting designations for different modes like CW, SSB, and FM to prevent interference, particularly with satellites and exotic modes like EME. Understanding and following the structured band plans not only ensures legal compliance but also optimizes frequency use and minimizes disruptions in the amateur radio community.

145 MHz is the target frequency for this 2-meter Skeleton Slot Yagi Stack antenna project. The design focuses on feeding two stacked Yagi antennas using a skeleton slot radiator, which is a unique approach for VHF enthusiasts. The project details the construction process, including the loop tapered matching section for impedance matching, ensuring optimal performance. The use of specific components like the EH789 element holder and MB456 main mast bracket is highlighted, providing clarity on the assembly process. The construction utilizes 20x20 box aluminum bar for durability and precision. Key dimensions, such as the element length (ER-ED4) and main boom spacing (MM123), are meticulously outlined. This attention to detail aids in replicating the antenna design accurately. The downloadable PDF offers comprehensive instructions, making it accessible for amateur radio operators interested in VHF antenna construction. This project is particularly beneficial for those looking to optimize their 2-meter band operations. The inclusion of a skeleton slot radiator and loop tapered matching section demonstrates advanced techniques in antenna design, catering to both intermediate and advanced builders.

Presents the design and construction of a folding 5-element Yagi antenna specifically engineered for 144 MHz portable operation, particularly for VHF contest Rover categories. It details element dimensions, boom construction using ¾-inch pine, and a folding mechanism that reduces the 52-inch boom to 26 inches for transport. The document provides a table with precise element distances and lengths, including a 2.4 mm length correction for solid parasitic elements, and specifies the use of 3/16-inch solid aluminum for parasitic elements and brass tubing for the driven element. It also covers the bent dipole driven element design for impedance matching, balun implementation with Type 31 ferrite beads for common mode current suppression, and weatherproofing for the feed point. The resource includes predicted performance data from 4NEC2 modeling, showing SWR and return loss characteristics, as well as gain and front-to-back ratios at various frequencies across the 2-meter band. It reports a measured SWR of 1.2:1 at 144.2 MHz and 1.5:1 at 147 MHz, corrected for 25 feet of RG-8/M coaxial cable loss. The design offers approximately 1.5 dB more gain than a previous 4-element design, maintaining a decent SWR up to 147 MHz, and was successfully deployed in a winning June 2016 ARRL VHF Contest Rover entry.

Constructing a **J-Pole antenna** from 450 Ohm ladder line for 2-meter (144 MHz) and 70-centimeter (440 MHz) operation involves specific calculations and assembly steps. The design, based on an earlier KD6GLF concept using 300 Ohm twinlead, features a ¾ wavelength radiator and a ¼ wavelength matching stub, functioning as an end-fed half-wave antenna without requiring ground radials. It offers a gain of 2.4 dB over isotropic. The resource provides the formulas for determining the lengths of the ¾ wave radiator and ¼ wave stub, incorporating a velocity factor of 91% for 450 Ohm ladder line. For 146 MHz, the radiator measures 55 3/16 inches and the stub 18 3/8 inches. Construction details include cutting a 57¾-inch piece of ladder line, stripping 4 inches from one end, and attaching a 24-inch section of RG58 or RG8X coax with a 3-5 turn RF choke. SWR adjustment is achieved by sliding a shorting bar or by incrementally trimming the elements at a 1:3 ratio (stub to radiator). The goal is a 1:1.1 SWR at 146 MHz, which typically yields 1:1.2 at 446 MHz. The article also discusses power handling, noting that while 10-15 watts is fine, 50 watts may increase SWR to 1:2.1, and advises keeping the antenna away from other objects to prevent coupling and SWR degradation.

Demonstrates the construction of a portable 2-meter repeater system utilizing a **Yaesu DR-1X** transceiver, configured for both analog FM and C4FM digital voice operation. The design emphasizes portability, robustness, and effective thermal management, incorporating a "wind tunnel" airflow system with a fan to maintain transmit module temperatures at 38 degrees Celsius during continuous operation. The system integrates a diplexer, control head, and is housed in a compact, lightweight case weighing under 8kg, designed for single-person deployment. Covers practical considerations for field deployment, including power sources, antenna types, and the overall system architecture for public service events and emergency preparedness. The resource details the modular "wrap around" construction, showing how components like thermal switches for fan control and Anderson Powerpole connectors are integrated. It highlights the system's ability to provide reliable communications support for club activities and emergency communications.

Demonstrates the conversion of an _Elecraft K2_ QRP HF transceiver to serve as a 2-meter Intermediate Frequency (IF) rig for microwave transverters, addressing the obsolescence of older _Yaesu FT-290R_ units. The project integrates a _DEMI 144-28DC_ transverter board, configured for a 28 MHz IF, and details the necessary modifications to the K2, including the installation of the K160M module for a separate receive-only antenna input and the KSB2 SSB module for voice operation. The modified K2 provides a stable 1-watt output for the 2m IF, utilizing the QRP antenna jack for transmit and the K160M input for receive, with a custom PTT control circuit. The article outlines the physical integration and electrical interfacing, including the design of an internal attenuator for the 28 MHz IF output and a control circuit for the 144 MHz interface. It also covers the construction of a medium power amplifier using an _MGA-31389 MMIC_ to boost the 2m output to 100 mW, matching the original FT-290R performance. Performance measurements for the amplifier, including output power versus input power and gain versus frequency, are presented. The project culminates in a fully integrated solution, with schematics and photos illustrating the internal wiring and external connectors. The modified K2, dubbed the "K290R," was successfully deployed in the 2017 _ARRL 10 GHz and Up Contest_ with a _Kuhne 10 GHz_ transverter, demonstrating reliable operation for CW and SSB modes.