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The fan dipole antenna as an alternative to the paralled dipole antenna, to achieve a larger bandwidth and a better tuning by decreasing elenment influences.A project based on the W6HDG original concept.

Enabling 10 and 12 meters band modification. This document explain how to do the modification to the PW1 in detail, with the aid of pictures & text

A dual band coax trap antenna designed to work on 20 and 30 meters or on 20 and 40 meters band by Phil W0XI

My Top Five Backyard Multi-Band Wire HF Antennas. A selection of the top 5 HF wire antennas for the backyard and for multi-band operation

A post about the construction and measurements of a Resonant Feedline Dipole cut for the 10M band

Third-order Cauer filters can boost performance of multi-transmitter, multi-operator contest stations to the next level. The filters are practical and you don’t need expensive test equipment to align them.

DK7ZB's fan dipole designs address the challenge of operating multiple HF bands with a single feedline, providing practical construction details for **multiband wire antennas**. The resource outlines specific lengths for half-dipoles across various band combinations, including 10-15-20m for classic bands and 12-17-30m for WARC bands. It emphasizes the importance of proper spacing between resonant elements to avoid impedance interaction and high SWR, a common issue when frequencies are too close. The article details the use of **current baluns** built with FT240-43 or FT140-43 cores, specifying turns and cable types for 1KW and 400-Watt power levels. It includes a correction table for adjusting dipole lengths based on frequency shifts, aiding in fine-tuning resonance. The 20+40m dipole is noted for its ability to operate on 15m with an ATU, demonstrating versatility.

The broad band hexagonal beam (hexbeam) designed by G3TXQ and built by K4KIO

How to homemade a multi-band HF dipole using 100 meter of speaker wire, 2 strandsm including a homebrew 1:1 choke balun

The AB2RA bowtie 80 meter antenna includes also a 40 meter dipole

The resource details the construction of a multiband trap-style Inverted-V antenna designed for operation on 3.5 MHz, 7 MHz, 14 MHz, 21 MHz, and 28 MHz. It presents specific winding data for the traps, including the number of turns, wire gauge, and coil former dimensions, crucial for achieving resonance on the target bands. The document provides a parts list and a diagram illustrating the antenna's physical layout and trap placement. It outlines the process for building the traps using PVC pipe formers and specifies the required capacitor values for each trap. The design emphasizes a practical approach to achieving multiband operation with a single feedline, a common goal for HF operators with limited space. The document includes a table with antenna segment lengths for each band, allowing for precise replication of the design. It also offers insights into tuning and adjustment, ensuring the antenna performs optimally across the designated amateur radio bands.

Hi-Z Antennas offers specialized high-impedance receiving systems, primarily focusing on phased vertical arrays for HF reception. Their product line includes preamplifiers designed for shortened vertical antennas, featuring optimized 15dB gain and array-matched characteristics. These components are engineered to enhance weak signal reception and improve signal-to-noise ratio across the HF spectrum. The company provides controllers for managing multiple vertical elements in a phased array configuration, enabling directional reception patterns. These systems are particularly effective for mitigating local noise and interference, a common challenge in urban and suburban operating environments. Specific offerings include solutions for 160-meter and 80-meter bands, addressing the unique requirements of low-band DXing. Technical details often reference components like the 2N3866 transistor in preamp designs and discuss concepts such as out-of-band attenuation. The focus remains on optimizing receiving antenna performance through impedance matching and active amplification, rather than transmit capabilities.

A simple project for an effective home made band pass filter, designed for the portable field day usage

This antenna article is geared towards new Hams and antenna builders looking for a very inexpensive 6 band antenna that can be efficiently fed with 50 ohm coax without a tune

Random Length Multiband Dipoles can be a good solution for field day operations or outdoor activity, read more at ARRL web site

HSMM Experiments on the 6M Amateur radio Band

An SSB radio for the HF bands will be presented. Featuring 12 to 20 Watts of output power (depending on DC supply), full DDS frequency generation, covering 6 major frequency bands (1.8, 3.5, 7, 14, 21 and 28 MHz) within the short wave amateur radio spectrum. The rig also features colored LCD and front panel backlight.

The QRZ.com callsign database serves as a fundamental resource for amateur radio operators worldwide, enabling rapid lookup of station information. Each entry, such as the one for _HB9DSP_, typically includes essential details for making and confirming contacts. Operators can find QSL routes, often indicating preferences like "via bureau or direct," which streamlines the exchange of QSL cards for award credit. Beyond basic contact data, these pages frequently offer insights into an operator's activities, including their participation in contests or DXpeditions. The platform also tracks metrics like "XML Subscriber Lookups," showing how often a callsign's data has been programmatically accessed, totaling **77670** for this specific entry. This functionality is crucial for logging software and other automated systems that rely on accurate, up-to-the-minute amateur radio data. While the page title mentions a "Home made multiband MOXON" antenna, the actual content primarily focuses on the callsign's biographical data within the _QRZ_ database.

A nice post on Make: on homebrewing a multiband antenna for amateur radio portable operations

The ÖVSV website provides extensive resources for Austrian radio amateurs, including details on its nine **Landesverbände** (regional sections) and the Austrian Military Radio Society (AMRS). It features information on licensing, legal frameworks, and **band plans** for both HF and VHF/UHF operations. The site also covers various amateur radio activities such as contests (HF, VHF/Microwave, Alpe-Adria, SOTA, ARDF), technical projects like WRAN, and educational content explaining what amateur radio is and how to become a licensed operator. Recent news items highlight events like the "Laa Funk '26" exhibition, the "OE5XLM" club station's participation in the CQ WW Contest, and the "International Marconi Day 2026" activation by "OE26M" from Küniglberg. The site lists upcoming events, including a 160m OE-Aktivitätsrunde, a seminar on Baluns/Ununs, and various club meetings and flea markets. Membership is facilitated through regional sections, and the site emphasizes amateur radio's role in independent communication during crises.

A clear TX wideband mod description for the FT-950. With pictures by PA1CA

G/T (Gain-to-Noise Temperature) is a critical figure of merit for evaluating the receive performance of VHF/UHF antennas, particularly for weak-signal work like EME (Earth-Moon-Earth) or meteor scatter. This resource presents extensive simulation data for numerous 2-meter and 6-meter Yagi antenna designs, originally compiled by _VE7BQH_ (Lance Johnson). The lists, updated as of October 2017, include various antenna models from designers such as _DK7ZB_, G0KSC, and K1FO, providing key performance parameters. Each entry details the antenna's G/T value, gain, front-to-back ratio, beamwidth, and VSWR at specific frequencies like 144.1 MHz or 145.0 MHz. The data facilitates comparison of different Yagi configurations, including those with folded dipoles and varying intrinsic impedances, aiding radio amateurs in selecting optimal antennas for their specific operational needs on the 2-meter and 6-meter bands.

Experimental Dual Band High Gain Flower Pot Antenna

Diamond W8010 Multiband Dipole Modifications

IARU Region 3 bandplan Revised 12 March 2019

Pictures and project design of a crossband VHF UHF repeater by LY3H

The direct conversion receiver described consists of only a bandpass filter, mixer IC, VFO and audio filter. With only 22 parts, this simple circuit should take a few hours at the weekend to construct.

Online calculator, Butterworth Bandstop (Notch) Filter Designer

A 200 kHz bandwidth digital transmission system for image transfer in the Amateur Service is under development, specifically targeting VHF allocations. John B. Stephensen, KD6OZH, leads this project under an FCC Special Temporary Authority (STA) valid until September 10, 2006, authorizing emissions up to 200 kHz bandwidth in the 50.3-50.8 MHz segment. Current regulations typically limit bandwidths to 20 kHz on VHF amateur bands, making this STA crucial for testing wideband digital modes. The modem, a modified **OFDM** (Orthogonal Frequency Division Multiplexed) unit, was initially tested on the 70-cm band. It splits a high-rate data stream into multiple low-rate subcarriers to mitigate multipath echoes. The system uses a DCP-1 card with a Xilinx XC3S400 FPGA and Oki Semiconductor ML67Q5003 microcontroller. The transmitter, located at 36d 46m 30s N, 119d 46m 22s W, generates 150 WPEP into an 8 dBi gain vertical antenna, while the mobile receiver uses a Ham-stick. Three data formats for 50, 100, and 200 kHz channels are being tested, with encoded data rates of 96, 192, and 384 kbps. Verilog code for the VHF OFDM modem is 95% simulated, with modifications from the UHF version including increased filter coefficient precision and a change from Ungerboeck **TCM** to BICM for improved performance over fading paths. Final tests will involve one-way over-the-air measurements of bit error rates and coverage area.

On this page are designs for Dual Band 2M / 70cm antennas. All antennas are 50 ohm designed driver. These Yagis have a unique element called a Open Sleeve. 4 Element 5 element and 9 element Dual Band - 2M / 70cm antenna projects

How to design narrowband bandpass filters

22 Different Wire Antennas for the 160 Meter Band, Random Length Radiator Wire, delta loop, loop antennas, off-centered antennas, sloper, dipoles, Z antenna, Zepp and Clothesline Antennas

A multiband trapped end-fed antenna can cover 20 30 40m bands. An option for portable sota operations were weight end simplicity are essential

Demonstrating the construction of a short dipole antenna tailored for the 60 meter band, this resource provides detailed instructions for radio enthusiasts with limited space. The design incorporates inductive loading using two inductors (L1/L2) made from PVC tubes, allowing for effective operation on 5 MHz. The antenna consists of 12 meters of wire, divided into four sections, with specific dimensions and materials outlined for optimal performance. Results from users indicate that this antenna can significantly enhance DXing capabilities on the 60 meter band. Feedback from operators suggests that while the design is effective, adjustments may be necessary based on individual setups, such as coil diameter and wire gauge. Many users report successful construction and operation, with some experimenting with variations to improve resonance. The practical application of this antenna design has led to successful contacts and improved signal quality, making it a popular choice among 60 meter band operators.

Clean Up Your Signals with Band-Pass Filters

A few thoughts on Multi Band VHF Aerials by Peter Ward VK3ZAV

This project is an interface box for the Yaesu FT-817 that includes a band output port, a computer serial interface, and a remote interface for the FL-7000 solid state power amplifiers.

21 28 and 50MHz three bands whip antenna by JA1HWO

Design and build a 6 meter 2-element Moxon antenna mostly from available aluminum tubing and angle stock.

6m/2m/70cm Yagi Antenna Built from Old TV Antenna This turned out to be a great little antenna. It works the 6 meter, 2 meter and 70 centimeter bands. You can use one common feedpoint or two seperate feedpoints depending on how you would like to connect this antenna to your transceiver.

PDF Manual for the RadioShack PRO-94 Radio Scanner

The Icom AH-4 autotuner operates efficiently across multiple HF bands, providing seamless automatic tuning for antennas from 3.5 MHz to 54 MHz. Its robust design allows for outdoor installation, making it suitable for field operations and fixed stations. The unit interfaces with Icom transceivers via a control cable, enabling automatic band switching and tuning. The AH-4 is capable of handling up to 120 watts of RF power, ensuring compatibility with most amateur radio setups. Its weather-resistant casing and compact form factor make it a versatile choice for operators requiring reliable performance in diverse environments. Field tests demonstrate the AH-4's ability to maintain low SWR across its operational range, enhancing signal quality and transmission efficiency. Compared to manual tuners, the AH-4 offers significant time savings and ease of use, particularly in rapidly changing band conditions. Its integration with Icom radios simplifies operation, eliminating the need for manual adjustments. The autotuner's performance is consistent with other high-end models, providing a cost-effective solution for amateur operators seeking dependable tuning capabilities without sacrificing performance.

A DIY Automatic Band Decoder (ABD) project, designed for dual-radio operation, addresses the common challenge of integrating band data with older transceivers lacking dedicated outputs. This particular build utilizes an AVR AT90S8515 microcontroller and a 16x2 Liquid Crystal Display (LCD) to provide band information, specifically targeting Kenwood rigs via a computer's LPT port. The design aims for cost-effectiveness while maintaining functionality, offering a solution for hams seeking to add automatic band switching capabilities to their station without significant expense. The project outlines the core components required, including the microcontroller, LCD, and an enclosure, noting that the Printed Circuit Board (PCB) fabrication and AVR programming might present challenges for some builders. It details the input requirements, such as a four-pin input and PTT for each radio, along with a 13.8V DC power supply. The decoder provides 2x6 outputs capable of sinking 500mA, suitable for controlling external devices like antenna switches or filters. Despite the original unit being damaged by a lightning strike in 2004, the author confirms its successful operation prior to the incident and mentions plans for a revised version. The resource includes a schematic in PDF format and images of the finished PCB and assembled unit, demonstrating the practical implementation of the design.

Optimizing weak signal reception on the HF bands, particularly in the presence of strong local QRM, often necessitates specialized receiving antenna systems. This resource details the _HI-Z Antennas_ product line, focusing on phased vertical arrays designed for superior noise rejection and directivity. It covers components such as the 4-Square and 8-Element array controllers, which allow for rapid switching of receive patterns, and dedicated low-noise preamplifiers to improve system sensitivity. The site also presents various bandpass filters, crucial for mitigating out-of-band interference and enhancing the dynamic range of the receiver. The HI-Z systems are engineered to provide significant front-to-back and side rejection, often yielding **20-30 dB** of attenuation to unwanted signals, which is critical for DXing and contesting. Users can achieve a notable reduction in local noise, allowing for the discernment of signals that would otherwise be buried. The array controllers facilitate quick pattern changes, enabling operators to null out interference or peak weak signals from distant stations, effectively extending the reach of their receive capabilities by improving the signal-to-noise ratio.

ON7YD narrowbands modes on 136 Khz

Will additional coax stubs improve Band Pass Filter performance?

An almost invisible wire antenna for the 17 meters band

MW0JZE Manufacturer of the G3TXQ Broadband Hexagonal Beam - HexBeam Antennas

Performance of an unloaded ground mounted vertical as a multi-band HF antenna.

These charts show the New Zealand bandplan