digital mode

SWR: Maximum allowable VSWR - VSWR (voltage-standing-wave-ratio) represents the degree with which an antenna is "matched" to the system impedance. Most modern antennas do not require any tuning for optimum performance. VSWR is one of the easiest parameters to measure and VSWR meters are becoming very popular antenna installation tools

Mobile Helix Antennas for HF - Normal mode helix antennas for HF mobile. Photos andn plan for a 20 meters mobile helix antenna by N2MH

Antenna Modelling - Antenna modelling notes, including wich antenna modelling software choose and where to find useful resources for antenna planning and home-brewing.

Antenna Modeling Files - A collections of antenna models submitted to arrl and can be used with NEC-4 or Yagi Optimizer modeling programs

45SD105 Vlada - Personal web site of a freebander, info on 11m digital modes, pictures of antenna projects

VU2LFA ham radio in india - This site is basically for the begeners (SWL) of india. This site is supporting to digital communication for hams also.

HAM Rádio BR / Feirnha DIGITAL - Brazilian free classifieds, links and more.

DCI Digital Communications Inc. - Filters, Duplexers, Combiners Bi-Directional Amps

RACOM - Radio modems - RACOM is a Czech company specialized in design and production of radio modems and other devices for wireless data networks for radio channels from 140 to 900 MHz. RACOM radio data networks are suitable for data transfer in telemetry & SCADA applications, transaction networks, security systems, IP networks and firts of all mobile tracking and fleet management.

Telewave - Telewave's innovative engineering produces the industry's toughest antenna systems. Yagi, Fiberglass Collinear, and Dipole models are available from 66-2500 MHz. Wattmeters, test equipment,rf power meters, duplexers, filters and cavities, transmitters combiners

About digital modes - The digital modes provide a wonderful opportunity for those of us who would like to work on the HF bands but find CW too difficult and SSB phone prohibitive because of interference problems. The digital modes are easy to set up and get operating, require low power and a narrow band.

Frequency Calibration for Weak Signal Work - Accurate calibration of your receiver and sound card is necessary for good results with the weak signal modes in use at LF. Modern receivers with master oscillators that are synthesized to provide all conversion frequencies greatly simplify the process. This article describes a method of making the necessary measurements and adjustments to an ICOM R75 receiver and a sound card, using the ARGO software

Iambic mode A and B - Document explaning the differences between Iambic mode A and B

WA4DSY 56KB RF Modem - This is a prototype of the WA4DSY 56KB RF modem. It is intended for use on amateur packet radio networks. The modem generates RF in the 28 to 30 mhz range and requires and linear transverter to convert the signal to a UHF or microwave ham band

CQ SSTV de KB4YZ - Amateur slow scan television and digital sstv by KB4YZ

Amsat DSP Satellite Transceiver Project - The DSP Satellite Transceiver is a conceptual transceiver designed as a dedicated unit for amateur satellite operators. The initial concept was brought about by the lack of satellite functionality on modern amateur radio transceivers, and the specialized requirements of the ham radio operator who utilizes OSCAR amateur satellites.

Kenwood ts-2000 and packet/digital mode - Using the TS-2000 for packet and digital modes. How to connect the Kenwodd TS2000 to TNC

Rocket Radio UK - UK based suppliers of CB, amateur radio equipment and DAB digital radios. Other products include antennas, base and handheld scanners, and accessories including microphones, books.

APRS-Beacon - The purpose of the APRS-Beacon is to provide simple APRS-compatible position beacons for up to three Objects. It is designed to 'stand alone' and does not monitor other traffic on the frequency. It can use a single-port TNC (in 'native' mode), a single- or dual-port TNC in Kiss mode or the AGW Packet Engine in order to transmit on up to four radio ports.(When running with AGWPE, APRS-Beacon will also work with Windows 2000)

Smith Chart Software - SimSmith is a highly interactive, real time Smith chart graphing program. Circuits are constructed using drag-n-drop. Load files can be imported from the EZNEC and CocoaNEC antenna simulation software and from the AIM4170 and miniVNApro antenna analyzers. Circuits and load files can be of any size. Key Features: SimSmith is one of the few Smith chart packages which models transmission line losses. SimSmith also allows the description of circuit elements using algebraic equations. SimSmith has only one screen and allows the screen to be resized to increase workspace or readability.

Konfabulator - DX Cluster Priority listing - Freeware windows XP and MacOSX konfabulator widget dedicated to Amateur radio operators, is an easy interface to DX-Summit the ham-radio DX Cluster. DX cluster spots represents live ham radio communication connections, and are an invaluable resource for amateur radio operators. Users can choose Bands or operating modes like digital emissions, QRP IOTA and more. Spots are refreshed automatically and refresh rate can be set by users, with a minimum of 100 seconds.

MMvari - MMVARI is a multi-Mode SoundCard Ham (Amateur) Radio program for receiving and transmitting the RTTY-PSK-FSK-MFSK modes. The program was written to experiment with the efficiency of transmitting Japanese and East Asian languages (HL/BV/BY) using the VARICODE

Digital Radio DCM - Programmable Digital Radio Receivers

A 80/40m Direct Conversion HF Receiver with DDS VFO - Juha (OH2NLT) and Matti (OH7SV) have designed JUMA-RX1, an award winning 80/40m direct conversion HF receiver with highly accurate direct digital synthesis VFO. The receiver is very compact, because it constructed using surface mount components. No coils need to be wound to construct this receiver!

Wavefront CompactPCI (CPCI) RF converter - The Wavefront CompactPCI (CPCI) RF converter provides a complete half-duplex radio front-end in an industry-standard 6U format. The architecture consists of dedicated receive and transmit channels that share a common RF interface.