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Specialize in servicing modern HF/VHF/UHF multimode transceivers and receivers Icom, Kenwood, Yaesu, and a few others

An interesting article by K3DAV comparing the COMET CHA250B to other HF multiband vertical antennas

TX RX Systems Inc. offers a robust catalog of RF conditioning products, including **transmitter combiners**, receiver multicouplers, and various RF filters. Their extensive experience, spanning over 45 years in the RF and Land Mobile Radio (LMR) industries, underpins their specialized offerings. They provide solutions for in-building RF coverage, repeater systems, and general RF management, catering to the demanding requirements of professional radio communications. Their product line features **bidirectional amplifiers (BDAs)**, signal boosters, and cavity filters, essential components for optimizing radio system performance. The company emphasizes reliable solutions, leveraging decades of field-proven expertise in designing and manufacturing critical RF infrastructure. From duplexers to cell enhancers, TX RX Systems focuses on delivering high-quality RF components and integrated systems designed to ensure clear and consistent radio signal integrity across diverse operational environments.

Article published on Practical Wireless about the W3DZZ multiband trapped dipole antenna made available by GM0ONX

miLog provides an integrated software solution for amateur radio station management, encompassing logging, DXing, and contesting functionalities. The software is designed to operate on Windows 2000 and later versions, indicating a focus on stability and compatibility within the Microsoft ecosystem. Its feature set includes comprehensive logging capabilities, tools for DX operations, and specific modules tailored for competitive contesting, streamlining the workflow for operators engaged in these activities. The resource details the software's commercial availability and its primary functions, which extend to station control. This integration allows users to manage multiple aspects of their amateur radio operations from a single application, potentially reducing the need for disparate tools. The description also highlights support for various operating modes, suggesting flexibility for different communication protocols and techniques. While the page itself is minimal, it serves as a direct point of reference for miLog, outlining its core purpose and system requirements. The emphasis on a highly integrated approach distinguishes it as a tool aiming to consolidate essential ham radio software functions.

DX Buddy is a multi purpose ham radio application that let you control your radios, or controller, offer a logbook, cluster access, qrz lookups, and interface with several popular ham radio applications

Ham radio antennas and electronics, specialized in 1/2 wave dipole, OCF dipole, windom, full wave loop, end fed, inverted L, portable end fed antenna, long wire, SWL antenna, fan dipole, multiband dipole, G5RV and military antennas.

Homebrew G5RV a simple multiband antenna. This article shows detailed pictures of a G5RV home made antenna, including antenna size and dimensions by 9M2ZAK

YF1AR multiband vertical antenna, based on orginal concept by VE7BS. Consist of 6 vertical elements and 6 base radials with a single 50 Ohm feed line.

The Collins TRC-75 autotune linear amplifier, owned by JF2SVU, is presented with a focus on its internal modifications. This QRO amplifier utilizes three 4CX250 tubes in parallel for its final stage, delivering 1 KW output power. Notably, the amplifier achieves full power with only 100 mW of RF input, a characteristic often associated with Collins designs. The original 400 Hz power supply has been converted for easier shack integration, and the entire RF and power supply sections have been rehoused into a compact, clean enclosure. The control unit, positioned above the amplifier, features three meters for individual vacuum tube IP monitoring and a multi-meter on the right. A dedicated 7 MHz receiver, recently completed, is also part of this integrated system. The autotune functionality means the main amplifier unit only requires connections for power, control, and coaxial cables, simplifying its operation. Key components like the 4CX250 tubes and NF capacitors are visible, along with the gearing mechanism for the final tank circuit. A timer and relay system manages high-voltage delay and cooling fan off-delay, although the cooling fan's airflow is noted as somewhat insufficient. A central volume control, which experienced a contact issue, is also highlighted.

This is a design for a stealthy HF multi-band vertical wire antenna using a tree as a supportby G7AQK

The G5RV multiband HF antenna, designed by Louis Varney (G5RV) in 1946, is a popular compromise antenna offering good overall performance on most HF bands when paired with an external antenna tuner. The basic full-size G5RV measures 102 feet across the top for 80 through 10 meter operation and is fed at the center via a 34-foot low-loss feed-stub. This interaction between the radiating section and the feed-stub facilitates matching across 80-10 meters with a standard tuner, often eliminating the need for ladder line directly to the shack. The antenna's design center frequency is 14.150 MHz, configured as a 3/2-wave dipole on 20 meters, with its 102-foot length derived from long-wire antenna formulas. Construction details emphasize the matching section, which can be open wire, ladder line (window-type), or TV twin lead. Each type has a specific velocity factor (VF) affecting its physical length for an electrical half-wave on 14 MHz; for instance, open wire requires 33.7 feet (VF 0.97), ladder line 31.3 feet (VF 0.90), and TV twin lead 28.5 feet (VF 0.82). The article provides formulas for calculating these lengths and discusses the antenna's behavior on individual bands, from 3.5 MHz where it acts as a shortened dipole, to 28 MHz where it functions as two three-half-wave long-wire antennas fed in-phase. Practical construction notes include recommendations for vertical descent of the matching section, sealing the coax junction, providing strain relief, and winding a coaxial choke coil to mitigate common mode current. The resource also presents dimensions for double-size (204 ft) and half-size (51 ft) G5RV versions, along with their corresponding matching section lengths for various line types, making it a versatile reference for hams considering this classic wire antenna.

A 9:1 voltage unun using a T-200-2 powdered iron toroid core to feed a long wire multiband antenna.

Construction details of a multiband dipole that can can operate at high power levels, and match its 50-ohm coax feedline without a tuner

An easy to make, cheap, no trap, multiband wire vertical antenna by PA1M

Operating a specialized DX cluster, this service provides real-time DX spots exclusively from stations confirmed to be _Log of The World_ (LoTW) users. This unique filtering mechanism allows DXers to prioritize contacts with stations that are highly likely to upload their logs to LoTW, streamlining the process of achieving confirmed DXCC or other awards. The cluster aggregates data from various sources, presenting a focused view of active LoTW participants across multiple bands. By narrowing the scope to LoTW-active stations, the platform significantly reduces the effort required for QSL management, as users can confidently pursue contacts knowing a digital confirmation is probable. This targeted approach is particularly beneficial for contesters and DXpedition chasers aiming for rapid award qualification, offering a strategic advantage in identifying viable contacts. The service supports both web-based access and traditional telnet connections, ensuring broad compatibility for amateur radio operators. It processes thousands of spots daily, with a focus on delivering accurate and timely information relevant to LoTW users, facilitating more efficient and productive operating sessions.

A New Twist on Portable Multiband HF Dipoles, a Multi-band Spiral Dipole Off-Center-Feed match (OCF) antenna solution.

The multiuser/multitasking BayCom Packet Terminal Driver program is a general purpose communications package for communicating with a BayCom modem attached to your IBM-PC/clone in conjunction with the TFPCX Baycom driver software. The software will also work with a normal TNC if it supports KISS mode, such as the Kantronics range.

Manufacturer of single band and multiband transceiver bandpass filters for HF. High pass filters, two radoi headphones mix and switch, 6 meter portable antenna, antenna remote switching and steering.

Free windows logbook program for SWLs, allow a quick and fast SWL logging during ham radio contests. Dupe check, utc time, partial check, cabrillo file export, multi language support

MSHV is a free windows and linux multimode software that support weak signal digital modes like MSK144 MSKMS JTMS FSK441 FSK315 ISCAT JT6M FT8 FT4 JT65 PI4 amateur radio modes. MSHV features several interesting features including the Multi Answering Auto Seq Protocol, allowing multiple signal transmissions to be used during dx peditions.

The Olivia transmission system is constructed of two layers: the lower, modulation layer is an (almost) classical Multi-Frequency Shift Keying (MFSK) and the higher layer is a Forward Error-Correcting (FEC) code based on Walsh functions.

An HF multiband trapped antenna in french

Many NDB radio enthusiasts publish their reception logs on the web. A completely separate system designed for individual listeners to make their own logs and obtain statistics on NDBs, DGPS and now Navtex Stations they have received. Log listings can be exported in a multitude of formats and then emailed to the NDB List

a methodology for connecting multiple LF/MF/HF receivers to a single antenna via readily available and inexpensive 75-ohm TV cable.

Multi-band loft-mounted dipoles for 40, 20, 17, 15, and 10m

The Fence Fan Dipole a quick, easy and inexpensive multiband dipole antenna

Alk engineering - filter design software and consulting

Interesting article on multiband fan dipoles. This article give an overview on designing this wire antenna, and planning a robust installation and proper feed line. Includes notes on setting up a commercial fan dipole antenna and on how diy your own.

This article explores the performance of an unloaded elevated vertical, base matching and feed line as a multi-band HF antenna system.

The Kenwood TS-2000 All-Mode Multiband Transceiver review

Germany's International Broadcasting Station with links to numerous pages in multiple languages containing program schedules, and live audio feeds.

The 2.1 kHz wide European LF allocation between 135.7 and 137.8 kHz is detailed in this observed band plan, offering guidance for activity within this narrow segment. It specifically addresses the challenge of locating weak signals, such as those from Slow-CW stations, which can have bandwidths of only a few Hertz. The resource emphasizes the utility of precise frequency knowledge when operating with narrow DSP filters, like a 30 Hz filter for CW, to differentiate multiple stations within a very small band segment. The plan, though not officially recognized, provides practical orientation for operators, particularly those new to the _LF band_. It references a similar plan published by the _RSGB_ in the January 2000 issue of _RADCOM_, suggesting a community-driven approach to band organization. The content highlights the importance of spectral awareness, noting that multiple stations can occupy minimal bandwidth, a concept illustrated by spectrographic analysis.

This article explores the performance of an unloaded vertical as a multi-band HF antenna.

Calnet a multi repeater amateur radio system serving most of California and parts of Nevada. The Calnet system consists of numerous fulltime linked 440 MHz repeaters connecting San Diego to San Francisco and Lake Tahoe.

Optimizing a G5RV or ZS6BKW multiband wire antenna for HF operation often involves addressing common SWR issues and understanding feedline characteristics. This resource chronicles the construction and performance evaluation of a G5RV, initially built for 80m, 40m, 15m, and 10m bands, by a newly licensed Foundation operator. The author details the selection of materials, including 3.5 mm stainless steel wire for the doublet arms and enameled copper wire for the open-wire feeder, and the initial decision to omit a balun based on common online information. The narrative highlights the initial disappointing performance, characterized by high receive noise and poor signal reports on 80 meters, despite the transceiver's internal ATU achieving a 1:1 match. This led to experimentation with a coax current balun and further research into G5RV myths, such as SWR claims and the necessity of a balun. The author then describes modifying the antenna to the ZS6BKW configuration, which involves specific changes to the doublet and feedline lengths, and integrating a 1:1 current balun wound on a ferrite toroid. The modifications resulted in improved reception and transmit performance across the bands.

An interesting article on random wire antennas, and how to choose the optimal lenghts for multiband operations.

Single Coax Feed to Multi-Band Copper Cactus Antenna.

A multiband vertical dipole antenna by ON4BAI

A small program to simplify changing messages in the Expanded Spectrum Systems Freakin' Beacon controller. The program makes it easy to modify an existing message or to have multiple messages available in different files ready to program into the beacon controller.

Details the Northern Amateur Relay Council of California (NARCC) as the regional coordinating body for amateur radio repeaters operating on the 10-meter band and above. It outlines NARCC's function in managing frequency allocations to minimize interference and ensure efficient spectrum use across Northern California. The resource specifies that NARCC operates in cooperation with the FCC and ARRL, indicating its recognized authority within the amateur radio community. The organization's role centers on repeater coordination, a critical aspect of VHF/UHF operations where multiple stations share limited frequency segments. It highlights the support received from local amateur radio operators, underscoring a community-driven approach to spectrum management. The site serves as a primary reference for hams seeking to establish or operate repeaters within the designated service area. NARCC's activities directly impact the operational landscape for _VHF_ and _UHF_ enthusiasts, providing essential guidelines and coordinated frequencies. This ensures orderly communication and prevents conflicts, particularly in densely populated areas of Northern California.

The _National Contest Journal_ (NCJ) serves as a dedicated resource for amateur radio contesters, providing in-depth articles, operational strategies, and technical insights. Published bimonthly by the ARRL, it covers a wide array of contesting topics, including antenna systems, station optimization, operating techniques, and rule interpretations for major events like the NA Sprint and various QSO Parties. The journal aims to enhance the competitive edge of participants across all skill levels, from casual operators to serious multi-operator teams, by sharing experiences and data from high-scoring stations. NCJ content frequently includes detailed analyses of contest results, offering breakdowns of scores, participant statistics, and comparisons of operating strategies. Readers can find practical advice on improving their contest performance, such as optimizing logging software usage or maximizing **run rates**. The journal also features columns on specific contest modes like RTTY and provides updates on rule changes and upcoming events, helping contesters prepare for future competitions and achieve better results, often leading to **top 10** finishes in their respective categories.

Unlocking the full multiband potential of the 225 Ohm elementary radiator in a folded monopole, dipole-like or turnstile layout, by Francesco Errante

Deploying robust antenna infrastructure for both fixed and portable operations often requires specialized support structures capable of withstanding environmental stresses while providing optimal radiating element placement. SMC offers a range of solutions, including pneumatic masts and push-up masts, designed to facilitate rapid deployment and reliable long-term support for various antenna types. Their product line encompasses antenna mounts, poles, and complete antenna systems, addressing the critical need for stable and efficient RF communication. The company's offerings extend to HF antennas, including dipoles and _NVIS_ (Near Vertical Incidence Skywave) antennas, which are crucial for short-range regional communications on bands like 80m and 40m. These systems are engineered for durability and performance, ensuring signal integrity across diverse operating conditions. With over **65 years** of experience, SMC has established itself as a global manufacturer in this niche. Their product portfolio also includes antenna support towers, catering to more permanent installations requiring significant height and load capacity for multiple arrays.

One point eight MHz to 30 MHz is the operational bandwidth for this 4:1 Ruthroff voltage balun, designed to interface an unbalanced T-Match network with a balanced antenna system. The project details the construction using a _T200-2_ powdered iron toroid core, tightly wrapped in PVC electrical tape for insulation, and wound with 17 double bifilar turns of 1.25mm enamelled copper wire. This outboard balun offers flexibility, allowing hams to trial various baluns based on antenna system and impedance characteristics, rather than integrating it directly into the tuner. The resource includes a schematic of the balun, a wiring diagram showing winding connections, and a table suggesting alternative toroid cores like the T80-2 or T400-2 with corresponding winding counts. Component sourcing is straightforward, listing items such as the _Amidon_ T-200-2 core, SO-239 connector, and a sealed polycarbonate enclosure from Jaycar. Performance evaluation was conducted using an _AIM 4170C_ antenna analyser, demonstrating efficient 1:4 voltage transformation across the specified HF spectrum. Further efficiency tests involved measuring RF power loss at various frequencies, revealing minimal loss—less than 0.7 dB from 3.6 MHz to 30 MHz, and only 2.0 dB at 1.8 MHz. These measurements, performed under ideal 50-ohm conditions, confirm the balun's effectiveness as a low-loss interface for multi-band antenna systems. The page also links to several other balun and unun projects, including 1:1 current and voltage baluns, and 9:1 voltage ununs, providing a broader context for impedance matching solutions.

Optimization tests of the W3EDP multi-band HF wire antenna a popular aerial among QRP enthusiasts because it is light weight and cheap.

The multiuser/multitasking BPQ Packet Terminal Driver program is a general purpose communications package for communicating with a packet TNC or Baycom modem attached to your IBM-PC/clone in conjunction with the BPQ Node software.

Optimizing the ZS6BKW antenna for full HF band coverage often requires specific modifications beyond its standard configuration. This resource details several enhancements, beginning with a simple series capacitor to improve 80m SWR, a technique W5DXP found effective for permanent installation due to its minimal impact on higher bands. Further improvements include a 10-inch parallel open stub for 10m resonance, shifting the frequency to 28.4 MHz with an SWR of approximately 1.8:1, a practical solution for Technician class operators. The document then explores a switchable matching section, adding or subtracting one foot of ladder line at the 1:1 choke-balun, which significantly impacts higher frequency bands and eliminates the need for a tuner on 17m. W5DXP's _AIM-4170D_ antenna analyzer measurements confirm these effects. More advanced modifications involve a parallel capacitor for further 80m SWR reduction, requiring remote switching for multi-band operation, and relay-switched parallel capacitors at specific points on the 450-ohm matching section to achieve low SWR on 60m, 30m, and 15m. These detailed steps, including _Smith chart_ analyses for the challenging bands, aim to transform the ZS6BKW into a truly all-HF-band antenna, reflecting W5DXP's practical experience in antenna tuning.

Prince Edward Island. The PEI DX Lodge offers a turnkey operation from a custom designed shack featuring state of the art transceivers/amplifiers, etc. and the ultimate in antennas on every band.

A complete guide to magnetic loop antenna construction, with analysis of multi-turn and single-turn magneti loops, and and insight on choosing the optimal capacitor, or homebrewing your own butterfly capacitor