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Thoughts build a solid state legal-limit amplifier for amateur radio use.

Drake TR-7 A.M. Transmit Filter Modification

The Southeastern VHF Society (SVHFS) is a not-for-profit organization incorporated to promote amateur radio operation on the bands above 50 MHz in the southeastern United States.

The RBN S-Meter visualizes real-time HF propagation data from the Reverse Beacon Network (RBN). It processes thousands of automated spots per hour, providing a real-time picture of active RF paths on HF bands. Users can set their vantage point using _Region Mode_ or _Grid Square Mode_. Region Mode allows selection from broad geographic areas like E. North America or Europe, while Grid Square Mode uses a Maidenhead grid square and radius for more precise data. The app displays eight region panels, each with horizontal bars for bands 160m through 6m, indicating signal strength with a color ramp from green to red. A dimmer trail shows peak hold values, and an S-unit readout provides additional detail. The app is a free web application accessible on any device, offering a practical tool for ham radio operators interested in CW, RTTY, and FT8 signals. It features a Progressive Web App installation option for enhanced usability on mobile and desktop platforms. Users can install it on Android, iOS, and Windows devices, providing a native app-like experience. The app replaces the previous Windows standalone executable, incorporating user feedback to improve features like grid square mode and automatic location detection.

DXLook is a free, web-based propagation platform that delivers comprehensive, real-time insight into HF and VHF conditions directly from any modern browser. It aggregates live spots from PSK Reporter, WSPRnet, RBN, and DX Cluster, complemented by NOAA space-weather metrics such as SFI, K/A indices, and geomagnetic alerts. Integrated VOACAP predictions allow practical "theory versus reality" comparisons, while the interactive world map with filters, gray line, and grid overlays enhances situational awareness. With no installation or maintenance required, DXLook provides a convenient, accurate, and accessible solution for everyday operating and propagation analysis.

Operating Free DV, the open source digital voice codec for HF, allows any SSB radio to be used for low bit rate digital voice.

An overview about the UHF connectors often referred to as the PL259 plug and SO239 socket used for many RF applications. Limitations, history and soldering properly UHF Connectors

This Guide helps you to build the 1:2 BalUn 600 Watts DIY kit step by step. If a delta-loop or quad-loop antenna is powered with a coax cable from the transceiver it is necessary to use a 1:2 BalUn. This 1:2 BalUn uses a symmetrical 1:2 impedance transformer.

A home made magnetic loop for HF Bands. This small and compact loop is designed to support small power transmissions on HF bands, from 7 MHz to 21 MHz

A 70 cm yagi antenna design by YU7EF includes tables with antenna elements dimension and spacing. This UHF Yagi antenna plan provides a maximum gain of 17.93 db

DF0WD DL4YHF Longwave Station include a linear transverter and antenna tuner

Benefits of stacking two HF antennas vertically

_AT Auto_ is an automatic antenna tuner designed for amateur radio enthusiasts seeking efficient and reliable tuning solutions. This device automates the tuning process, allowing operators to focus on communication rather than manual adjustments. The tuner is compatible with a range of transceivers, enhancing its versatility in different shack setups. Its design incorporates advanced circuitry to ensure optimal performance across various bands. The _AT Auto_ tuner is particularly useful for those operating in HF bands, providing seamless transitions between frequencies. Its integration capabilities with other shack automation products make it a valuable component for modern amateur radio stations. The tuner supports multiple modes, including _SSB_ and _CW_, catering to diverse operating preferences. Its robust construction and user-friendly interface contribute to its appeal among both seasoned operators and those new to the hobby. Kessler Engineering's focus on innovation and quality is evident in the _AT Auto_'s design. The tuner is part of a broader product line that includes shack automation solutions, reflecting the company's commitment to enhancing amateur radio operations. Despite the website redesign, the tuner remains a key offering in their product portfolio.

This project describes a DIY all band HF SDR transceiver. Built around a Softrock 6.3 kit, it boasts a 20W homebrew amplifier and ATmega168 microcontroller for USB control. An LCD displays frequency, power, and SWR. Automatic LPF selection and SWR protection enhance functionality. Compatible with Rocky and PowerSDR software, this project provides a cost-effective and powerful HF SDR transceiver for hobbyists.

A Web forum dedicated to HF underground and in particular to Shortwave Pirate Radio Forums and Spy Numbers listenings

DL1OFC, operating from Hankensbüttel, Germany, shares insights into the fascinating hobby of amateur radio. While the station has been on hiatus since 2016, the site provides a valuable archive of activities and technical information. DL1OFC was active across various bands and modes, including 145.225 MHz FM, 430.225 MHz FM, 29.600 MHz FM, and DMR via DB0AGM on TS-1 TG-262 DL. Shortwave operations included SSB on the 40m through 10m bands, as well as 6m. The site details regional amateur radio activities in and around Hankensbüttel, offering a glimpse into local field days and community involvement. A notable feature is Die Isetalrunde, a regional amateur radio net covering the area from the Harz mountains to the sea. The site also includes general information on radio technology, tips for obtaining an amateur radio license, and discussions on VHF/HF propagation, including specifics on the 70 MHz band.

The TBJ-1 – a triband base antenna was published in March 2017 QST. This antenna covers 2M/220 MHz/70cm in one 6ft 3/4 inch PVC pipe and requires no radials.

The PG7V Contest Calendar provides a curated listing of significant **HF contests**, with a particular focus on events relevant to European amateur radio operators. It details contest specifics such as start and end times in UTC, eligible bands (e.g., 80 meters, 40 meters, 10 meters), and required exchange information (e.g., serial number, CQ-zone, DOK, locator, age). The calendar includes diverse modes like CW, SSB, PSK63, RTTY, and FT4, catering to various operating preferences. Featured contests include the RSGB 80m Club Championship, WW WPX Contest, IARU Region 1 Fieldday, and ARRL International Digital Contest. Each entry links directly to the official contest rules for detailed information. The calendar also notes specific participation rules, such as the 1 KHz QSY requirement in the HA3NS Memorial Contest or the 24-hour single-operator time limit in the ARRL International Digital Contest. This resource is updated regularly, ensuring timely information for upcoming **contest operations** over a four-week period. It serves as a practical tool for hams planning their contest activity.

Pictures and description of a multiband HF mobile setup by N4AIT

Elements are aluminum TIG soldering rods 4.0mm of diameter, almost 1m long, these objects are light, thin and flexible based on the RZ9CJ Design

The page provides information on a simple 50MHz J-Pole Antenna project based on the DK7ZB design. It explains the principle of the Wireman-J-Pole, the feeding process, practical mounting, and simulation results using MMANA GAL. The content aims to guide amateur radio operators in building their own J-Pole antennas for the 6-meter band.

If you thought you knew everything about balun performance characteristics, there is an important figure of merit you may have neglected

Restoring a 1965 Collins 618F-1A VHF aircraft radio. This radio was designed for light aircraft as an early frequency-synthesized radio built in 2 separate chassis.

FTB8800 is a memory management software program for the FT-8800R/E FM transceiver

Drake R-4 Receiver manual

This EXCEL Program Worksheet calculates the safe operating conditons for a toroidal transformer operating between 1 and 50 MHz. Manufacturer data for complex permeability, magnetic dimensions, and saturation flux density must be available. Some core types which are commonly used in amateur transmission are included. The program produces limiting winding voltages for linear operation and temperature rise over the range of frequencies and power specified.

Antuino is an accurate instrument that can be used in the field to measure SWR, field strength, modulation, etc. In the lab, it can be used to sweep filters, measure gain, distortion, frequency response, etc. It works upto 150 Mhz. On the third harmonic, it is usable on 435 Mhz band as well (with reduced sensitivity).

VHF/UHF FM Mobile Transceiver with APRS and EchoLink Functionality official Kenwood UK site

UA9QCQ site was created as a website for those who participate in various ham radio contests. In the dedicated section, you can view the competition schedule of events. Each event has link to the ruole of competition. Events data is updated monthly on the eve of the next month. We try to ensure that our info contains only up-to-date data.

The MIT UHF Repeater Association maintains the W1XM Repeater which is located on the top of the Green Building.

The Laurel Highlands VHF Society, Inc. owns and operates the Acme repeater, located on the Chestnut Ridge in southwestern Pennsylvania.

An interesting review of the Icom 2720H VHF UHF amateur radio mobile transceiver with pros and cons

FTB7800 is a memory management software program for the Yaesu FT-7800R/E FM transceiver

Amaterur radio blog from Cordoba Spain

The problem with making your own trapped HF antennas is usually getting the coaxial traps tuned to frequency. This article explains a method using a RF signal generator at +10dBm output into the coaxial trap.

IARU HF Contest, goal is to contact as many other amateurs, especially IARU member society HQ stations, around the world as possible using the 160, 80, 40, 20, 15 and 10 meter bands.

Amateur Packet Reporting System (APRS) operations often require compact, reliable solutions for transmitting position data, particularly for mobile or portable stations. This resource details the construction of the _Tiny Track-I_, a transmit-only APRS tracker designed for straightforward integration with a VHF radio and a Global Positioning System (GPS) receiver. It enables hams to broadcast their location without the complexity of a full-duplex TNC. The project outlines the printed circuit board (PCB) layout and schematic, based on an original design by N6BG, with a personal PCB drawing by SV1BSX. It includes specific component placement and notes an additional 10uF/10V capacitor (C5) for improved IC voltage decoupling, a modification not present in the original N6BG diagram. The unit connects to a computer or GPS via a DB9 female connector. This tracker is ideal for basic position reporting, offering a simple and effective way to participate in APRS networks. Its small footprint makes it suitable for vehicle installations or field deployments where space is limited, providing a **reliable 9600 baud** data stream for location updates.

A small, easy to build, copper tube magnetic loop antenna for the 2 meters band. In Italian

Mitigating impulse-type noise, a common challenge in the **HF radio spectrum**, often requires specialized processing before the signal reaches the transceiver's receiver stages. The NR-1 addresses this by functioning as an RF interference removal device, specifically a noise blanker, targeting transient noise sources. Its operational range extends from 1.6 MHz to beyond 70 MHz, making it suitable for various amateur radio bands and general shortwave listening applications. Unlike QRM eliminators or X-phasers, the NR-1 does not require a separate noise antenna for its operation, simplifying its integration into existing station setups. The device's design focuses on wideband performance, allowing its use both within and outside the allocated amateur radio frequencies. Documentation detailing its operation is available, providing insights into its technical specifications and deployment. This unit is a hardware product, conceptualized and implemented by SV3ORA.

A not-for-profit organization incorporated to promote ham radio operation on the bands above 50 MHz in the southeastern United States.

Drake Radio Service & Repair, Refurbishing Services

Our ideas about HF baluns have changed dramatically in recent years. The focus today is very much on suppressing unwanted common-mode RF currents, to reduce both the received noise levels and the risks of causing interference on transmit.

A deep analysis of UHF connectors performance tests, including return Loss of UHF Connectors, Mismatch Loss of UHF Connectors, SWR of UHF Connectors

The structure of this dual band VHF UHF antenna is very simple. It consists of two identical square loops, whose sides measure a quarter wave, connected together at the ends. A project by I5NZR

This is a Solid State Amplifier Project. It uses 4 MRF150 MosFet Power Transistors. The Power Supply Voltage is 50 VDC at 21.5 Amp. The max power available is 1,075 Watts. The Efficiency is about 65% +/- and runs Class AB Solid State.

The Itchen Valley Amateur Radio Club (IVARC) provides a local hub for radio amateurs in the Southampton and Winchester areas of the UK. This club actively participates in various UK contesting events, including the weekly _RSGB VHF UKAC_ contests, _RSGB AFS club contests_, and _BERU contests_, alongside annual UK field days. As a _Brickworks Accredited_ club, IVARC is committed to supporting both new licensees and experienced operators in exploring diverse aspects of the hobby, fostering skill development and operational experience. Meetings are held on the 2nd and 4th Friday of each month at the Bianchi Suite, Otterbourne Village Hall, offering a consistent schedule for members and visitors. The club's recent activities include supporting _Jamboree On The Air_ (JOTA) for local Scout groups (e.g., GB1ESG), activating special event stations like _GB0SR_ from Solent Rescue Lifeboat Station, and organizing club visits to significant historical sites such as Bletchley Park. IVARC also hosts events like QRP Day and National Field Day, providing practical operating opportunities and fostering camaraderie among members.

FTB2800 is a memory management software program for the Yaesu FT 2800 M FM transceiver.

JT65 software download archive for all JT65 editions, includes a JT95 and JT9 operating mode informations, JT65 reference website for Japanese operators.

For every radio amateur who loves to travel by car, a mobile installation soon becomes a necessity. While in inhabited areas there is usually some coverage of VHF repeaters, in many other places VHF radios are useless. In these very places, HF can provide reliable contacts, and a lot of fun, from anywhere.

The CobWebb antenna project is a compact, multiband HF solution ideal for amateur radio operators. Covering 14-28 MHz, it features a square dipole array with near-omnidirectional coverage and unity gain. This guide details a DIY approach, using a 1:4 current balun for impedance matching. Construction involves aluminum and fiberglass tubing, with optimized element tuning for SWR performance. Weather resistance improvements and resonance shift considerations are also discussed. Build your own CobWebb antenna for an efficient, space-saving HF experience.