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Shareware dual channel audio spectrum analyzer for Windows 2000/XP which can provide either a scrolling time-frequency display or a spectrum analyzer scope display in real time for any sound source connected to your sound card. Can be used for MTHELL, QRSS and DFCW by R S Horne

Presents the WA7BNM Contest Calendar, a long-standing resource for amateur radio operators seeking contest schedules and rules. Bruce Horn, WA7BNM, compiles comprehensive listings that include an _8-Day Calendar_ for immediate planning, a _5-Week Calendar_ for near-term strategy, and a _12-Month Calendar_ for broader outlooks. The site also offers specialized views like the Perpetual Calendar for predictable events and a dedicated section for State QSO Parties. Operators can access historical data back to **2005** and customize their calendar views to filter for specific modes or QRP power levels. The calendar integrates with modern tools, providing RSS feeds, iCal downloads for desktop calendars, and direct links to Google Calendar for seamless integration. This resource is a staple for contesters, offering essential details like log due dates and links to official contest sponsor rules.

This Antenna is not really practical for AO-40 reception, but horn antennas have a number of qualities useful in microwave antenna testing and noise figure measurements.

Demonstrates _Freq51_ and _Specgrm2_, two analysis programs from the Biomedical Ultrasonics Laboratory at the University of Michigan, available for DOS or Linux. The _Spectrum Analyser (Freq51)_ provides power spectrum levels as a function of frequency, configurable for absolute values (e.g., dB re 1 volt) with sound card calibration. _Spectrogram (Specgrm2)_ generates a real-time, full-screen spectrogram (sonagram) with various color options. These programs analyze incoming signals in real time, not stored files, and offer extensive settings for sampling rate, FFT points, and averaging time, making them highly versatile for acoustic analysis. The DOS version of _Freq51_ and _Specgrm2_ can operate under Windows 95, requiring users to configure sound card switches via a text file. The resource also briefly mentions other acoustic analysis software like Gianni Pavan's DOS-based bioacoustic tools, _Gram_ by R.S. Horne for Windows, _SASLab_ (Light and Pro versions), _Cool Edit_, and _GoldWave_, providing a comparative overview of available tools for real-time and file-based spectral analysis and waveform manipulation.

Demonstrates the construction of a 2.4 GHz horn antenna, specifically designed for WiFi applications, with the potential to add several dB of gain. The resource focuses on the critical dimensions and calculations required for proper operation, including _wavelength_ (Lo) and guide wavelength (Lg) based on the operating frequency (Fo) of 2.442 GHz, corresponding to channel 7. The guide provides a table of European WiFi frequencies, ranging from 2.412 GHz to 2.477 GHz, highlighting the specific channel 7 as the design target. It details how the length of the waveguide (Lg) depends on the diameter of the enclosure, offering a practical approach to antenna construction. This project outlines the necessary measurements like Lo/4 at **31 mm** and provides a link to an external calculator for further design specifics. The horn design aims for a 30-degree beamwidth, making it suitable for focused signal transmission or reception.

The ARRL page, titled "The HF Mobile Antenna," serves as a curated index to various _QST_ articles focusing on constructing mobile HF antennas. It presents several projects for the mechanically inclined amateur, suggesting that homebrewed antennas can achieve efficiency comparable to commercial versions. For instance, one entry details a **five-band** antenna for RVs, utilizing a fold-over Hustler 4BTV, while another describes a "Bug Catcher" design for 80 through 10 meters. Further projects include a budget-friendly $20 HF mobile antenna made from PVC and wire, covering 20 through 6 meters, and the "Alpha Special," a multiband horizontal antenna originally for 1960s station wagons, now suggested for mini-vans. The resource also addresses antenna mounting solutions specifically for travel trailers and campers, providing practical insights for those operating from recreational vehicles. Rounding out the collection are the "Connecticut Longhorn," a 75-meter horizontal whip with remote tuning, and its redesign, the "Connecticut Shorthorn," adapted for smaller vehicles post-1970s. This compilation offers a historical perspective on mobile antenna innovation and practical construction guides for various HF bands and vehicle types.

KARSFEST, held at the Will County Fairgrounds. Sponsored by the Kankakee Area Radio Society. Large and well attended hamfest and computer show!

A Tomato Can Horn antenna for 2304 MHz by Steve Kavanagh

The article details a specific method for performing maintenance on a crank-up tower, focusing on cable and rotator replacement without a full power pulldown. It outlines the necessary equipment, including a 2-section extension ladder with a horn attachment and a two-piece, 6-foot steel pipe, specifying a 1 1/4-inch diameter. The procedure involves lowering tower sections onto the internal pipe to slacken cables, allowing for their removal and replacement, and also describes how to replace the rotator while the tower remains upright. Key steps involve using the pipe to support tower sections, enabling access to the cables and bearings. The author, N5AR, emphasizes safety by instructing the reader to remain on the ladder at all times, rather than climbing the tower itself. The process is presented as manageable for a single operator, with the author having successfully completed the task on a _UST TX472_ tower. Specific tools mentioned include Allen wrenches and end wrenches for cable ends and bearing bolts. The method provides a practical approach for tower upkeep, minimizing the complexity often associated with such tasks and allowing for maintenance of components like cable pulleys and their bearings.

About basics of the horn antenna used for many rf microwave antenna applications.

Dual mode horm antenna for 10 GHz nu G3PH0

Horn Antennas theory and principles

Dedicated to the art of Ham Radio, enhancing individual operational and technical skills as well as providing communications during local and national emergencies. Located on the Kenai Peninsula in South Central Alaska.

An overview of the basics of the horn antenna used in RF microwave applications.

Antenna design for Horn Antennas

A Horn antenna by WE3HHT

Havering and district Amateur radio club based in Hornchurch, Essex

The Horn reflector antenna at Bell Telephone Laboratories

Developing operational amateur radio equipment for the 134 GHz band presents significant technical challenges, particularly in frequency generation and stability. This resource details the construction of a 134 GHz system, outlining its architecture with separate transmit (Tx) and receive (Rx) modules, each employing a local oscillator (LO) and RF head units. The system utilizes a dual Flann 50 GHz lens-type horn antenna configuration for optimal signal coupling. The transmit path incorporates an LMX2541 synthesizer chip operating at approximately 2.8 GHz, referenced by a 10 MHz double-oven Morion OCXO for exceptional stability. This signal is multiplied through a series of stages (X4, then X2) to generate a 22.4 GHz signal, which subsequently drives a dual series diode multiplier to produce the final X6 signal for 134 GHz operation. The receive side features an anti-parallel diode mixer coupled to a 144 MHz transceiver via a preamplifier, ensuring effective downconversion. Operational mode is CW, achieved by keying a multiplier stage. The project includes images of the Tx and Rx head units and describes a successful 3.5 km test with G8ACE, demonstrating stable signal tones due to PLLs locked to OCXOs at both ends, confirming the system's robust performance.

Measuring noise fiugre on the W2IMU horn and the dual-dipole-feed

Vintage radio and scientific apparatus by john jenkins, include antique radios, Horn Loudspeakers, Vacuum Tubes, A.C. Receivers

The TECLA Thirty, an early wireless age crystal set, is featured among a gallery of over 100 collectible headphones, with detailed close-up photos of vintage models. Several pages offer vintage headphones for sale, including Brandes, Baldwin, and Western Electric, suitable for crystal set use or collecting. Construction details are provided for a reproduction KILBOURNE AND CLARKE crystal set, built with vintage 1920s parts and featuring a miniature variable condenser for fine tuning. The resource also presents a project for a simple crystal radio and a 1-tube amplifier, complete with a schematic and component diagram, suitable for driving a horn speaker or amplifying weak signals for headphones. Instructions for mounting argentiferous galena detector crystals are included, along with information on MRL Handbooks covering crystal detectors and modern diodes. Additional projects include a 2A3 single-ended triode tube amplifier and two stereo tube amps using 12AX7, 6V6, 5Y3G, 6SN7, VT-25, and 5U4G tubes.

This PDF document outlines the process for establishing an **OpenWebRX+** station utilizing Software Defined Radio (SDR) devices on a Linux platform, specifically Debian Bookworm. It details the capabilities of such a setup, including reception across various frequency bands supported by the SDR hardware and the decoding of multiple modes like FM, WideFM, SSB, AM, ADSB, FT8, and CW, with examples provided for FT8 reception and mapping, sensor data, and ADSB. The guide recommends specific hardware configurations, suggesting older x86-64 laptops with 4GB RAM or Raspberry Pi 4 models for the host system. For SDR devices, it endorses **RTL-SDRv3/v4** or HackRF, noting the necessary driver installations for RTL-SDR. The software installation sequence is meticulously laid out, from installing Debian Bookworm to adding OpenWebRX+ repositories, installing the application, and configuring device-specific drivers. Authored by Christian Horn (JL1AYH), the resource also includes a brief personal background of the author. It concludes with instructions for accessing the OpenWebRX+ interface via a web browser, either locally or remotely over a network, and provides contact information for further inquiries.

The club is based in chingford, north east london

TSGARC Amateur Radio club Thornbury & South Gloucestershire Englang UK

Elkhorn Valley Amateur Radio Club Norfolk

In this project by building a W2IMU feed horn, the author successfully optimized their 10GHz Small Dish EME project. To position and solder the components together, they used a jig and a conical section made of copper sheet. Stability was ensured by fitting the XLNA to the WG switch. The WG components were shod into a waterproof plastic container, and the feed horn and WG were surrounded by a collar and skirt that were 3D printed. With an average Moon noise of 0.5dB, the Sun and Moon noise readings were better than their previous configuration.