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Mods and articles collected by mods.dk

Amateur radio Services by the Federal Communications Commission.

General Mobile Radio Service Frequencies

This project shows how to build a 50-ohm dummy load using non-inductive resistors, oil for heat dissipation, and a simple assembly process. It enables accurate transmitter tuning, testing, and power measurement across LF to UHF bands. The setup allows meter calibration by measuring peak voltage, applying diode drop correction, and calculating RMS voltage and power precisely. Parts are inexpensive and widely available. With proper assembly, this dummy load offers extended service life, accurate readings within 2%, and a reliable alternative to costly commercial wattmeters for amateur radio applications.

Over 40 years of experience inform the reviews and commentary presented on Dave's Radio Receiver Page, covering a wide array of radio receivers and transceivers. The resource details specific models such as the **ICOM IC-R8600** SDR Communications Receiver, which is lauded as Icom's best wide-band receiver, even surpassing the IC-R9500 in performance. Other notable reviews include the ICOM IC-7300 HF Transceiver, highlighting its direct sampling SDR technology and spectrum scope capabilities, alongside numerous models from Japan Radio Co. (JRC), Kenwood, Yaesu, and various portable shortwave receivers. The content provides practical insights into the performance and characteristics of each radio, often drawing comparisons between models. For instance, the early issues with the AOR AR7030 receiver's Bourns mechanical encoders are thoroughly documented, including AOR's eventual switch to higher-quality Alps encoders. The page also features reviews of antennas like the MFJ-1026 Noise Canceling Signal Enhancer and various power supplies, offering a holistic view of radio monitoring setups. The author's "2 ear / 2 eye method" emphasizes real-world listening experiences over laboratory measurements, providing a unique perspective on equipment utility.

How connect a common PC headset with microphone to the Yaesu FY-817, FT-857, FT.897 in italian by I6IBE

The ZS6BKW multiband HF antenna, a design by ZS6BKW (G0GSF), functions effectively on multiple HF bands without requiring an Antenna Tuning Unit (ATU) for 40, 20, 17, 12, 10, and 6 meters. This antenna, approximately **27.51 meters** (90 feet) long with a 12.2-meter (40-foot) open-wire feeder, is a direct descendant of the _G5RV_ but offers superior multi-band resonance. It can be deployed as a horizontal dipole or an inverted-vee, with the latter requiring only a single support and maintaining an apex angle of at least 90 degrees to prevent signal cancellation. Performance data, recorded with an MFJ Antenna Analyser, indicates SWR values of 1:1 on 7.00 MHz (40m) and 14.06 MHz (20m), with SWR below 1.3:1 on 17m, 10m, and 6m. While primarily designed for these bands, the antenna can be adapted for 80m, 30m, and 15m with an ATU, preferably at the balanced feeder's base. The use of 450-ohm twin-lead for the feeder is recommended over 300-ohm for improved strength and reduced losses, especially in adverse weather conditions. This design, originally published in _RadCom_ in 1993 and featured in Pat Hawker’s "Antenna Topics," provides a compact and efficient solution for HF operation, particularly for those with limited space or resources.

University of Texas Amateur Radio Club RF-Calculator. This is a main beam power density estimation program intended for use as part of a routine evaluation of RF safety compliance with FCC regulations

Linking VHF and UHF radios and repeaters around the world using a secure Voice-Over-IP system, with no hackers!

An adjustable VSWR, 2 meter J-Pole

RadioReference.com, scanner frequency and radio communications reference source, with complete conventional frequency assignments, trunked radio system information, frequencies, and talkgroups, FCC License assignments and maps, 10-Code Lists, agency maps, files, downloads, links, and detailed agency information for most public safety, military, and local government activities.

The G3TPW Cobwebb antenna covers five bands, 14 - 28 mhz, including the WARC bands

Solar Flux reports, Current Alerts and Warnings from NOAA, 27 day forcast from NOAA, charts reflecting the past 7 years Solar cycle summary charts from NOAA

Multimode suite, feature logging, Internet interface to CXCluster, Smart multi-mode controller software, contest, APRS, and PSK31 via Sound card. Free and Commercial version available.

Radio programming programs for YAESU and ICOM handheld transceivers. VX-7 Commander, VX-2 Commander, VX-5 Commander, VR-120 Commander, and IC-R2 Commander. All software on this site is designed to work on Windows 9x, ME, NT, 2K, and XP.

A moxon antenna for 28 MHz

Old Time Radios ! a good resource to old time-radio amataurs

A DIY discone antenna project made to improve receiveing performance of an RTLSDR receiver.

Freeware antenna software that lets you see what the polar diagram of your rotatable beam actually looks like where it is operating. With PolarPlot you can measure the polar diagram of the antenna and check for abnormalities - compare plots taken before and after changes to the design or location - check the -3dB beamwidth - look at the front to back ratio - see the size and position of the sidelobes.

"ARES trains and organizes Hams to provide emergency communications to ""Served Agencies"" such as FEMA, National Weather Service, Red Cross, Salvation Army, Hospitals, and others. This site describes ARES goals and methods and structure."

SDR Software defined radio kits, genesis SDR kits

Kenwood TS-830 manual, tips and fixes

N2DS home made loop page collection.

The **NW3Z** optimized wideband antenna designs, originally presented at Dayton 2001, detail Yagi configurations for the 20-meter, 15-meter, and 10-meter amateur radio bands. This resource provides access to the design files, likely containing critical parameters such as element spacing, element lengths, and boom dimensions, which are essential for replicating these directional antennas. The designs focus on achieving wide bandwidth, a desirable characteristic for contesters and DXers operating across a significant portion of each band. The content specifically references "nw3z-Antenna-DesignsDownload," indicating that the core information is available as a downloadable file, presumably in a format suitable for antenna modeling software or direct construction. Such files typically include **NEC models** or similar data, allowing for performance analysis and optimization before physical construction. The emphasis on "optimized wideband" suggests design considerations for SWR bandwidth and gain characteristics over a broader frequency range than typical narrow-band Yagis. The resource serves as a direct source for specific, proven antenna designs from a known amateur radio antenna designer, offering practical data for hams interested in building high-performance Yagi arrays for HF.

G4NCE's illustrated vintage military wireless collection. Featuring British, Canadian and New Zealand Army eqpt, and Royal Air Force eqpt, from WW2 and the 1950's.

A free to download and print, amateur radio station log sheet in a paper US letter format

2 element Yagi antanna plan from G3SYC

Kenwood TS-2000 Review

Tim Kirby IC-706 review of this small portable Icom transceiver

Illustrates the fundamental principles of radio repeater operation, detailing how different duplex configurations overcome signal limitations in varied terrains. It begins by contrasting _simplex_ communication, where all units share a single frequency, with more complex systems designed for extended range and specialized applications. The resource systematically presents each mode, from basic base station setups to advanced multi-frequency configurations. The content specifically covers hemi-duplex systems, often used in commercial dispatch, where the base station transmits on one frequency and mobiles on another, without rebroadcast. It then progresses to semi-duplex repeaters, the most common type in amateur radio, which automatically retransmit received signals on a different frequency. The explanation extends to demi-duplex and hemi-demi-duplex systems, which incorporate multiple control links for enhanced operational flexibility and secure communications, as seen in public safety applications. Finally, the resource clarifies full-duplex repeater systems, exemplified by cellular networks, where simultaneous two-way communication is achieved through distinct transmit and receive frequencies for each direction. The visual aids, including **9 distinct figures**, effectively demonstrate the signal paths and frequency assignments for each operational mode, providing a practical understanding of repeater architecture.

Collection of Amateur radio packages for the Raspberry Pi devices

A small multiband antenna for vacation in french

Halo antenna for 4 meters band with dimensions, pictures and assembling instructions

The Adcock antenna has been used for a long time for RDF. It is basically an interferometer.

"Sells high voltage film and electrolytic capacitors for antique tube radios. Carries 630 volt metal-film, metallized and mylar film capacitors as well as electrolytics. Also has ""capacitor"" tips for antique radio restorations."

What is the best WiFi antenna for me? Looking for a range extender antenna for your WiFi system. This article will help in choosing the correct antenna for your system

Download the PDF with USA Amateur radio HF band plan and common country prefixes updated in 2008 by Icom

OZ2OE Technical pages, a 3 element 28 MHz light weight Yagi for 10 meters band

Mobile vertical antenna for 144 MHz suitable for satellite signals reception by K5OE

RTTY Tutorial by K4WW, foundamentals, FSK and AFSK

Manuals of US Military radio equipment

A friendly dx net who welcomes new comers to amateur radio and the serious dxer alike; Daily from 2000gmt on 14.208mhz. Listen the net live.

Indoor wire antenna for 7 mhz from F6CYV

If you have a small lot and want on 160 meters this is our version of the antenna by K5CBL Troy

Presents the product lines and corporate information for Japan Radio Company (JRC), a long-standing manufacturer of radio communication equipment. The company's offerings span various sectors, including marine, land, and aviation communication systems, alongside their historical contributions to amateur radio with notable **HF transceivers** and **shortwave receivers**. JRC emphasizes its technological expertise in areas such as radar, satellite communication, and network solutions, contributing to global safety and security infrastructure. The resource details JRC's commitment to leveraging its accumulated knowledge and experience in information and communication technology. While the primary focus has shifted towards commercial and governmental solutions, the legacy of JRC's amateur radio products, such as the JRC JST-245 transceiver and the NRD-525 receiver, remains significant within the ham radio community, known for their robust build quality and performance.

How to make a Weatherproof Vertically Polarised Omnidirectional Aerial, The Slim Jim Antenna

Radio worldwide on shortwave with schedules

Amateur Radio experience, blog from Florence Italy

A project by DL5DBM for a VHF UHF antenna suitable for handheld transceivers