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a Javascript for calculating the lengths of tubing to be used for the construction of a Super J-Pole.

Selecting an appropriate antenna system for shortwave broadcasting involves evaluating various types based on performance, cost, and operational parameters. This resource details the critical specifications for broadcast antennas, including average and peak power ratings, directivity, takeoff angle (TOA), horizontal beamwidth, and gain, emphasizing that a 100-kW transmitter requires an antenna rated for 150 kW average and 400 kW peak. It clarifies that low TOA signals travel thousands of kilometers, while high TOA is for local coverage, and nearly all modern shortwave broadcast antennas are horizontally polarized. The article explores specific antenna types, such as Log-Periodic Antennas (LPAs), which offer wide frequency ranges (e.g., 2-30 MHz) and directional patterns with 11 dBi gain, costing from $20K to over $100K for multi-curtain versions. Dipole arrays, also known as curtain antennas, are prevalent in international broadcasting, featuring steerable beams (±15° and ±30°) and mode-switching capabilities to alter TOA, with high/low pairs costing over $1 million. Fan dipoles are noted for omnidirectional patterns, smaller size, and lower cost for low-power applications, while rhombics, though simple, require resistive termination and incur several dB of I2R losses. Balun considerations are crucial, as most communications baluns are not rated for the higher average and peak powers of AM broadcast transmitters. Modern shortwave antennas utilize durable materials like Alumoweld wire rope for radiators and support elements, avoiding copper, fiberglass, or materials prone to stretching or deterioration. Feeder systems for high-power stations often require tapered-line baluns to convert 50-ohm unbalanced power to 300-ohm balanced for connection to the antenna.

Macintosh audio spectrum analyzer that allows the user to view live audio in a standard frequency plot, a stereo oscilloscope view and a waterfall display

Aviation Radio Service by FCC

The total length of this antenna is 41m, height is about 11m, and diameter of element is 2mm. JA7KPI modified this antenna originally used as Inverted-V type of 80m band Dipole. Works on 40 - 80 meters band with acceptable swr.

Construction tips to build an automatic``satellite tracking rotor controller using``PIC16F877 IC.

The 30/40 meter **vertical antenna** project by IK4DCS details the construction of a shortened, self-supporting design, reaching a total length of 5 meters. The antenna incorporates a linear loading section and a coaxial cable trap for 30 meters, based on the "Antenne Volume 2°" text by Nerio Neri (page 223). The design uses six radials, three for each band, positioned at approximately 90° inclination and at least one meter above the roof or ground, connected via a 1:1 balun at the feed point. Mechanical construction utilizes aluminum tubing, with a 2.30-meter primary radiator section (30 mm diameter) joined to a second part using a Teflon insert and a PVC sleeve for rigidity. The linear load, approximately 3.70 meters long, accounts for a 30% physical shortening of the quarter-wave element. A capacitive load, made from three 50 cm radials, is integrated into the 40-meter top section for fine-tuning. Final adjustments involved radial inclination for 40 meters, as initial testing showed increased SWR and interference on 30 meters due to nearby resonant structures. The author emphasizes the importance of clear space for optimal performance and provides drawings and photos to clarify the build process.

Info on this discontinued HF Transceiver

Automatic SWR meter and semi-automatic tuning unit by F1FRV

This homebrewed antenna tuning unit also incorporates a 50-ohm QRP dummy load, power meter (1 or 10 Watts full scale), and SWR meter

DX Toolbox searches the web for you, gathering information on solar and geomagnetic conditions that affect radio propagation. It's ideal for the ham radio operator, shortwave listener, or other radio enthusiast.

Here is a simple and easy to build antenna in a Delta Loop configeration that should make 10 and 12 meters lots more fun if you have a limited space situation o

Indoor multiband dipole with EZNEC data files for simulation and analysis. Includes details on construction, tuning, SWR plots, and software usage. This page includes two different dipoles, a first version for 20-10 meters and an extended version covering 40-10 meters allowing a full coverage of most used ham radio HF Bands.

This free windows software allows you to decode digital signals like FLEX, POCSAG, ERMES, MOBITEX and ACARS.

The Carpet Loop II is an inexpensive, easily built, high performance antenna that can work in almost all apartments.

Build a 10 Meter Technician Class Dipole antenna. Get on 10 Meters fast with this basic 10 Meter Dipole project by hamuniverse

How High should my Dipole be? Dipole Antennas - the Effect of Height Above Ground

A very interesting and informative introduction to the 50 MHz band, also known as 6 meters or better the Magic Band, by Dave Finley N1IRZ, covering different propagation modes, operating experiences, and the excitement of the band. The content provides insight into the unique characteristics of six meters and its unpredictability in signal propagation.

Create Online Maps, Check Forcasts and Conditions, more features being added each month, by hfradio.org

Rigid Dipole antennas for 14 MHz band using PVC and Aluminium tubing

Table of allocation of international Call Sign series

A reversable quad antenna for 40 meters band by N4JTE

A full size half-wave 30m dipole installed in an attic

Description of PSK31, mailing list, frequency for QSO

Build a Multi-Band Mono Delta Loop for 40, 30, 20 and 15 Meters.

Regenerative short wave radio schematic

A 6 elements VHF Yagi antenna designed with YAGIMAX 3 and made by SV1XY with excellent results on local and satellites contacts like UO-14 and AO-27

Antenna modelling techniques and examples by W4RNL

A small and inexpensive measurement device designed to determine antenna performance across the amateur bands through use of automatically collected SWR readings

Dipole, Yagi, Vertical, Cubic quad, Log periodic, J-pole, coil, and transmission line design package for the Macintosh

Weather demodulator software, cards and antennas.

Design and build your own Hf thru Vhf antennas.Contains pictures, plans, parts list of very popular ham antennas along with experimental types.

Hammock 2 element wire Yagi antenna for 3 bands 20-15-10 based on VE7CA project

So you want to build a Beverage Antenna. This article offers insights on building a two-wire Beverage antenna for better reception. Key points include using long wire (at least a wavelength, ideally two), keeping it straight and away from vertical conductors, and sloping ends for noise reduction. The author recommends copper clad wire and mentions transformer design considerations for later discussion.

The most flexible and powerful Microwave and RF Filter and Multiplexer Design Software. Download Filpro-student.zip

A quick and easy to build loop antenna for shortwave listeining can tune from 5 to 18 Mhz

A shortened and invisible wire antenna for 7 MHz

Freeware real time DSP filter particularly for applications of amateur radios , IIR, FIR filter, low-pass, high-pass, band-pass filter, band suppressor (notch filter) individually adjustable

An HF QRP CW RTX built around the Arduino open-source electronics prototyping platform

The AZIMUTH program plots a world map in either azimuth (beam heading) or Mercator projections. If you specify your home location in latitude and longitude, the azimuth projection is centred on your location. The Azimuth map program can display Maidenhead grids - this is useful for 6m, 2m, and UHF DX communication display. Various features of the map are: Azimuth or Mercator projections , Maidenhead grid display, Simple map zooming, Print maps with adequate resolution up to one meter sized map

An old satellite frequency list from 3 to 8475 Mhz dated 1996

Calculating and building an Eggbeater antenna. InstantTune and push-button Rx. Documentation available in french and english

Yaesu FT-817 Portable QRP MF/HF/VHF/UHF Transceiver, an assortment of technical information

A Site to help you get started in QRP, including building your own QRP radio.

Modifications, improvements and setup of the Yaesu FT-2000 at DK3HV

William Hepburn's Daily Tropospheric Ducting Forecast.

Pictures and homebrew instructions for this collinear 2.4 Ghz antenna

The Petlowany Three-Band Burner is a simple, low-cost, trapless short vertical antenna which amazingly works on three HF bands (20, 15 and 10 meters). This web page contains pictures, performance data, and enough construction details so you can homebrew your own.

Method of storing my portable wire antennas.

How to make a wifi cantenna using a mini ravioli can