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An experimental antenna, similar to the _TAK spiral antenna_, was evaluated for SWR response over the 7.0 to 7.3 MHz frequency range. The analysis presents specific results: beam length significantly affects SWR, with increased distance between spirals raising the resonant frequency; the combined length of antenna and hookup wire lowers the resonant frequency as it increases; and spiral diameter impacts bandwidth, with larger diameters yielding greater bandwidth. The design addresses the fixed beam length limitation of the commercial TAK antenna by introducing an adjustable version constructed primarily from PVC electrical conduit and water pipe, using 14-gauge aluminum wire. The resource includes a detailed mechanical design, construction steps, and a parts list. It also features a spiral antenna spreadsheet model for calculating design parameters like start point, pitch, safe edge, spoke length, and arm length, which aids in determining wire length and kerf cutting tables. Model verification involved constructing an antenna to specific parameters, with SWR tests conducted using an _MFJ Model 269_ antenna analyzer at 13 feet above ground with 60 feet of RG8 mini coax. Measurements showed that adjusting beam length from 27 to 37 inches shifted the resonant frequency by approximately 0.18 MHz. Further data compares 32-inch versus 48-inch diameter spirals, demonstrating increased bandwidth for the larger diameter. The model accurately predicted revolutions for given antenna lengths, pitch, and starting distances. The final design achieved a resonant frequency of 7.17 MHz, favoring the voice portion of the 40-meter band after adjustments.

Project of a windom multiband antenna for 10 to 80 meters in portuguese

6m to 40m EndFed Half Wave Antenna project produces an inexpensive, multiband, end fed HF antenna matchbox that is quick and easy to setup and use.

APRSISCE/32 is an Automatic Packet Reporting System (APRS) program, primarily intended for Windows and Windows Mobile (CE), although it will run on Linux and Mac OS under wine. Offer enhanced messaging, announcement support via ANSRVR, and QRU for object query support, can run as a highly configurable Digipeater

Modifying the _ICOM IC-706MKII_ transceiver for out-of-band transmit capability involves specific surface-mount device (SMD) removal on the main circuit board. This procedure enables transmit functionality from 0.5 MHz to 200 MHz, excluding the commercial FM-Wide broadcast band, significantly expanding the radio's operational frequency range. The modification requires careful handling of small components and a fine-tipped, low-wattage soldering iron. Prior to beginning, all programmed memories and initial setup configurations must be noted, as the modification process will erase them. The instructions detail the necessary tools, preparation steps, and the precise location of the two SMD diodes to be removed. These diodes are situated near an oblong crystal can and a test point labeled _CP3_ on the main board. Successful completion returns the unit to its default configuration, necessitating manual reprogramming of memory channels and initial settings. This project is suitable for operators with experience in SMD work and fine soldering.

The document details the optimization and construction of the _Maria Maluca_ antenna, a compact 6-band (20m-6m) directional beam. It presents a comparative analysis of shortwave antenna principles, highlighting the efficiency gains achieved by using an open feeder line and tuner as a resonant unit, contrasting this with the losses associated with traps or capacitive loads in multiband antennas. The resource specifically revisits an older South American 2-element design for 10, 15, and 20 meters, applying modern NEC-based software to develop a six-band version. Performance data is meticulously tabulated, showing impedance, free space gain, gain at 12m height, elevation angle, and front-to-back (F/B) ratio for each band from 20m through 6m. For instance, on 15m, the antenna achieves 5.1 dBd free space gain and 13.72 dB F/B ratio. The construction section provides practical guidance on element assembly using aluminum pipes and hose clamps, detailing the use of a heavy-duty glass fiber reinforced polyamide rod for electrical separation and bending strength. It also specifies the use of 450-ohm _Wireman_ line CQ 552 for the transmission line. The document includes diagrams for rod fixing, an air-wound balun, and a vertical elevation diagram for the 15m band, illustrating its DX qualification. It also discusses the antenna's suitability for portable and expedition operations, noting its compact transport dimensions (max 1.50m length, 12 lb weight) and quick assembly time (under 15 minutes). The author, Dipl.Ing. Helmut Oeller, DC6NY, is identified as a source for material kits.

Why the G5RV is a good antenna on 75m and 40m

The intent of this site to share information about the design of a 40 meter horizontal phased array antenna.

The alternative multi-band solution, covers more bands than a G5RV, light weight, won't damage your trees.

Clean up audio files and record high quality audio CD's!

2 meter & 70 centimeter mobile halo antenna project, by N6TWW Mike Fedler

Specialized, business and industrial radios

This signal generator is intended for realignment of radio receivers

The PIC-MORSE is an electronic iambic keyer, integrating a generator of Morse code and a sidetone. It is built with a microcontroller PIC16C711. In French

The purpose of this web page is to try to investigate the ICOM IC-746PRO Dead TX problem reported by many radio amateurs through out the world; and unfortunately not properly taken care of by ICOM. If you are the owner of either the ICOM IC-746PRO or the IC-7400 you may already have experienced the Dead TX Issue. If not you may sooner or later.

Software for radiomonitoring, radio spectrum analysis. MDS is designed for the real time radio spectrum analysis. It performs real time activity analysis, signal search and collects spectrum data for post time analysis.

W1ZY's 40-meter **Moxon** antenna project details nine months of experimentation, culminating in a reversible array built from No. 12 insulated wire. The design incorporates two RF current baluns and a unique two-wire element construction, where each element consists of two parallel wires spaced 3 inches apart. The resource provides specific dimensions for the first prototype, including A=50.98', B=7.87', C=1.25', D=9.3', and E=18.42', optimized for 7.050 MHz CW operation. It thoroughly explains the construction of custom two-wire insulators from Plexiglas semi-rods and the critical pre-tensioning process required to maintain wire separation and array integrity. The author, Bill, emphasizes the antenna's exceptional receive performance, noting a 30-35 dB front-to-back ratio, which allows for significant signal rejection from the rear. While the Moxon offers 5-6 dB gain on transmit, its primary advantage lies in its ability to radically reduce rear-facing signals on receive, a characteristic Bill believes is often overlooked in transmit-focused comparisons. The guide details a flexible tuning method using removable tail-end jumpers, enabling adjustments to both tail-end and parallel dimensions without re-soldering the feed point, a technique refined over three prototypes.

A Compact size 80-10 m field day antenna offering a Low angle of radiation and very easy to build and set up

Theory, Modeling, and Practical Applications By W5JCK, presentation in PDF File. This presentation focuses on Near-Vertical Incidence Skywave (NVIS) antennas, which are crucial for short-range radio communications, particularly in military and emergency contexts. It explores NVIS theory, antenna models, and installation criteria while debunking common myths about reflectors. Key topics include usable frequency bands, optimal installation heights, and the impact of soil quality on performance. The presentation outlines the best bands for daytime and nighttime use, emphasizing the importance of understanding propagation characteristics to enhance communication effectiveness within 200 to 300 miles.

Freestanding aluminum towers manufacturer

Amateur Radio Ham Radio Maidenhead Grid Square Locator Map online. This map allow just a point and click to determine dynamically the correct six characters locator. Other functions allow to calculate the distances among two given locators, or coordinates. Hover over map, specify grid, or enter latitude and longitude to show grid and/or calculate distance. Map is powered by Bing Maps.

HF Communications Analysis and Prediction Tools for Amateur Radio and communications professionals. Featuring: WinCAP Wizard, Beacon-Time Wizard, GeoAlert-Extreme Wizard, ID Wizard, KTS Clock Screen Saver, NERDAlert 2000

The Super J Pole antenna is a co-linear vertical consisting of a number of half wave length vertical elements separated with half-wave length stubs (Tuning stub) feed with a folded matching stub by vk6ysf

Homebrew project of a vector network analyser VNA by N2PK

This software predicts future passes for amateur radio satellites for a specified location and period of time. It runs on the Android operating system

Free program that interfaces most ICOM radios with the ILG radio frequencies database and lets you click a station in the database to tune your radio to the station, or scan the list looking for stations that are on the air.

ScanOhio Marine Radio frequencies

Interesting variant on the 3-element Yagi. Lightweight fiberglass (or similar) tubes supporting a wire structure of elements

Scancat-Lite-Plus for Windows supports the memory programming for Radio Shack and Uniden Scanners

A few images to use as a desktop background.

Australia's busiest radio related classifieds site. Free instantly online adverts from the VK/ZL area.

Comparison chart between Cushcraft R8, Hy-Gain AV640 , Butternut HF6V, Gap Titan and Eco 7+

Ham Radio, SWL and electronic kit manufacturers

The article "Exploring the World of 10 Meter Beacons" by Ken Reitz, KS4ZR, provides an in-depth look at 10-meter beacon operations, focusing on their utility for propagation analysis. It details FCC Rules part 97.203 governing beacon stations, including license requirements, power limits (under 100 watts), and the specified band segment of 28.200-28.300 MHz for U.S. operations. The content highlights the diversity in beacon construction, from converted CB radios to home-brew QRP transmitters, and discusses the robust operating conditions these 24/7 stations endure. The resource presents several case studies of active 10-meter beacon operators like Ron Anderson KA0PSE/B, Domenic Bianco KC9GNK/B, and Bill Hays WJ5O/B, detailing their equipment, antenna setups, and typical signal report volumes. It also introduces the NCDXF/IARU International Beacon Project, which features 18 synchronized beacons worldwide transmitting on 28.200 MHz at varying power levels (100W, 10W, 1W, 100mW) to facilitate propagation testing. The article also covers the PropNet Project utilizing PSK31 on 28.131 MHz and the 250 Synchronized Propagation Beacon Project on 28.250 MHz. Practical advice for monitoring includes using the RST reporting method, understanding the impact of the solar cycle on 10-meter propagation, and tips for setting up a personal beacon, such as frequency selection and power output considerations. The IY4M Guglielmo Marconi Memorial Beacon Robot on 28.195 MHz is also mentioned for its automatic QSO mode. The article concludes with a list of other resources for 10-meter beacon information.

Dynamic Map Progam with 34 maps, 442 overlays, and realtime position/locator info. Online Demo available. 0-59c per map.

Manufacturer of Fibreglass Whip Antennas, Low and mediun Frequency, HF and VHF Antennas Specialized in the design and manufacturing of a full range of Beacon (MF), AM Broadcasting 540 - 1700 KHz, HF 1.7 to 30 MHz, VHF 30 to 156 MHz and UHF 200 to 500 MHz antennas.

Almost a fresh QSL manager Database, Country Tables for YPLOG by VE6YP (updated monthly), Additional files for the TRLoog by N6TR. Technical topics for HF Contesting (mostly CW), software download (a huge collection)

7 dB for 7 Bucks, a 2 meter beam antenna for the cost of a fast food meal!

A compact antenna contender for 160 meters.

Project and schematic of a regenrative receiver by AA5TB

A database which allows the user to store and catalog QSL cards

Article about omega and gamma matching, related to bandwidth, loss and component failures, heating and power ratings

Morse Code Keyers / Processors and other PIC products. CW RTTY serial and usb interfaces and keyers kits.

Icom IC-9100 pre release product infomration

160m T Antenna broadcast design by Guglielmo Marconi has been built and is used by Jim NN4AA on 160m. Article by G7LRR

Radio scanner frequencies for nsw

JTSync is a simple utility that provides the ability to synchronize your computer clock over a network with world-wide NTP servers. When the Internet connection is not available, JTSync allows you to make time adjustments based on decoded QSOs within the WSJT-X application.

Large picture of a 2011 amateur radio map with DXCC country list

This page is a short description of the four phased verticals system i've build and used. It is primarily intendend to be used on the lower bands 160m, 80m, 40m.

Kenwood, AOR, CB antennas and accessories.