hf radio

638 links - and 12 categories

IAT Interactive Antenna Table - IAT is an excel sheet table evaluate parameters of VHF UHF antennas edited by Vladimir UR5EAZ. The difference between this tool and the existing VE7BQH Antenna Table is the use of G / T and C / N instead of the G / Ta parameter. In this table, Vladimir applies the ITU recommendations to assess the noise properties of a radio receiving system and shows the advantage of the G / T concept over the G / Ta concept when choosing an antenna.
[ Hits: 106 | Votes: 4 | Rating: 9.5 ]
Double Quad Antenna for VHF UHF - 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
[ Hits: 247 | Votes: 6 | Rating: 6.33 ]

W3DZZ Multiband Antenna - An easy to build and extremely high performance antenna, works perfectly on all HF bands 3.5-28 MHz with some compromises, it is basically an half wave dipole for 40-80 meters, an LC circuit or trap 40 meters allows you to use a single radiating element.
[ Hits: 464 | Votes: 3 | Rating: 7.67 ]

Building a VHF Contest Station - Building an amateur station for competitive radiosport involves a number of critical steps, regardless of the band or bands you focus on. These include, but are certainly not limited to: Station layout, Equipment interconnection and switching, Inter-station interference, Antenna selection. Radio interface with the logging program, CW and voice keyer integration, Rotator control
[ Hits: 336 | Votes: 1 | Rating: 4 ]

Pirate QSL Collection - A QSL Cards collection divided into North American Shortwave Pirate Radio QSLs abd European Shortwave Pirate Radio QSLs
[ Hits: 118 | Votes: 0 | Rating: 0 ]

Central States VHF Society - The Central States VHF Society, Inc. (CSVHFS) is a not-for-profit organization chartered in the state of Missouri. It was begun in the mid-1960s to foster amateur radio operation on the bands above 50 MHz.
[ Hits: 55 | Votes: 0 | Rating: 0 ]

Automatic Position Reporting System for HF - A basic introductionto APRS on HF Bands for radioamateurs and how to setup an APRS tracker using Argent Data Systems T3 Mini TNC device, configured and assemble ready for portable operations.
[ Hits: 150 | Votes: 0 | Rating: 0 ]

Operating AMTOR - Putting one of those old modems back into use.AMTOR is an acronym for AMateur Teleprinting Over Radio and was mostly used on HF. The mode is based on the marine SITOR code that was introduced to amateur radio by Peter, G3PLX. The mode is an enhancement of RTTY with active error correction that copes reasonably well with interference and fading.
[ Hits: 81 | Votes: 0 | Rating: 0 ]

FreeDV - Digital Voice for HF bands - FreeDV uses an audio codec as a software based modem to decode and encode the voice and text data from your computer. The data is encoded and then is transmitted over the HF radio using AF signals that can then in turn be decoded by the receiving station.
[ Hits: 92 | Votes: 0 | Rating: 0 ]

Global Ionosphere Radio Observatory - In cooperation with the URSI Ionosonde Network Advisory Group (INAG), the LGDC promotes cooperative agreements with the ionosonde observatories of the world to accept and process real-time data of HF radio monitoring of the ionosphere, and to promote a variety of investigations that benefit from the global-scale, prompt, detailed, and accurate descriptions of the ionospheric variability.
[ Hits: 125 | Votes: 0 | Rating: 0 ]

HF communication prediction tools - Online HF Communication prediction system provided by the Australian Governament Buerau of Metereology allow to predict usable frequency rage for radiocommunications between two stations allowing to specify frequency and date range. This tool allow calculation with different methods and algorithms
[ Hits: 169 | Votes: 0 | Rating: 0 ]
Tropospheric Ducting Forecast Europe - The areas noted in the forecast have the necessary atmospheric conditions to produce tropospheric bending of VHF, UHF and/or microwave radio waves. Tropospheric bending extends the range of radio & TV stations well beyond their normal limit and thus increases interference amongst stations as well.
[ Hits: 157 | Votes: 1 | Rating: 10 ]

Radio Equipment : HF Transceivers

FLEX-6400M DSP Review - A guest review of the FLEX-6400M DSP HF Trasnceiver considering just the receiver part of this radio.
[ Hits: 136 | Votes: 0 | Rating: 0 ]

Radio Scanning : Military

Monitoring The Airwaves During Ukrainian Conflict - This article reports and collect some frequencies used during 2020 Ukraine war and reported as being used by army forces. HF communications are still a crucial part of military communications and can ben monitored on web sdr radios available on the internet.
[ Hits: 530 | Votes: 3 | Rating: 9.67 ]

Radio Scanning : Scanner Frequencies

Scanning frequencies - HF digital mode transmissions, voice transmissions in HF and VHF Bands collected in several XLS files by Relic Radio communications
[ Hits: 139 | Votes: 0 | Rating: 0 ]

Spy Numbers Stations - Spy Numbers Stations are shortwave radio stations that are speculated to have been broadcasting since World War I. The true origin and purpose of them are unknown. A popular theory is that these stations are intended for spies in the field using a One Time Pad. Another theory is that they are used in drug smuggling operations.
[ Hits: 176 | Votes: 0 | Rating: 0 ]

432 MHz 100W RF Power Amplifier - This article describes the construction of a 100-Watt, 70 cm amateur band linear power amplifier. It is the result of a protracted period of experimentation during which I investigated a number of final amplifier stages from obsolete UHF FM 2-way radios.
[ Hits: 239 | Votes: 1 | Rating: 9 ]

70cm Beacon - PLL synthesized 70cm CW beacon exciter. The exciter is built arround a slightly more advanced ADF-4351 single chip PLL synthesizer rather then (among amateurs) more popular Si-570 or Si-5351 integrated circuits. The exciter is capable of providing up to 250 mW of RF output power,
[ Hits: 130 | Votes: 1 | Rating: 10 ]

EA2CW Nanokeyer - HFN (Hands Free Nanokeyer) is a 3D Printer made morse keyer. In this project the athor shares the STL printer model files for the 3 versions build.
[ Hits: 97 | Votes: 1 | Rating: 10 ]

Tulip SDR - SDR Project for a compact amateur radio software defined radio trasceiver covering HF bands all mode. Website includes schematics, element PCB, pictures, movies, firmware and elements bom.
[ Hits: 369 | Votes: 5 | Rating: 8 ]