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RadioRaft decodes 10 different ARQ modes, 8 different FEC modes, Packet, Baudot, CW... It works with a Hamcomm interface or a radiomodem. RadioRaft offers automatic detection of modes, speeds and shift. It comes with a frequencymeter/baudmeter included, it has signal frequency tracking and a bit by bit display mode. Very easy to use. practical and fast.

Mods.DK serves as a central repository for **amateur radio modifications**, offering a substantial collection of user-contributed articles. Hams can find detailed instructions for various equipment, from transceivers by Yaesu, Kenwood, and Icom to microphones and power supplies. The database, currently holding 6230 articles, facilitates searching for specific equipment modifications, such as enabling out-of-band receive and transmit capabilities or integrating high-speed packet modems for enhanced data communications. Many entries focus on achieving better performance from existing gear, often detailing how to expand frequency coverage for MARS/CAP operations or optimize radios for 9600 baud packet. The site also includes repair instructions and general improvements for a wide array of HAM rigs and modems, reflecting a community-driven effort to share technical knowledge. Users are cautioned that modifications are not verified by Mods.DK and are undertaken at one's own risk, with potential legal implications depending on local regulations. The platform emphasizes community support, encouraging direct contact with authors or forum discussions for troubleshooting.

Packet/telemetry modems, GPS tracking, sound card interfaces

Weatherfax decoding software with modem

This is a packet radio software developed for amateur radio operators to provide IP communications. You can chat, send/receive e-mail, surf the web and so on via radio depending on your bandwidth. You don't need a TNC. You might have all of TNC features via SoundCard using SoundModem.

Amateur Radio Projects & Kits for homebrewers, includes DDS,sound card interface,programmers, hamcom, frequency counter, RF Power Meter, modems and more.

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

A 200 kHz bandwidth digital transmission system for image transfer in the Amateur Service is under development, specifically targeting VHF allocations. John B. Stephensen, KD6OZH, leads this project under an FCC Special Temporary Authority (STA) valid until September 10, 2006, authorizing emissions up to 200 kHz bandwidth in the 50.3-50.8 MHz segment. Current regulations typically limit bandwidths to 20 kHz on VHF amateur bands, making this STA crucial for testing wideband digital modes. The modem, a modified **OFDM** (Orthogonal Frequency Division Multiplexed) unit, was initially tested on the 70-cm band. It splits a high-rate data stream into multiple low-rate subcarriers to mitigate multipath echoes. The system uses a DCP-1 card with a Xilinx XC3S400 FPGA and Oki Semiconductor ML67Q5003 microcontroller. The transmitter, located at 36d 46m 30s N, 119d 46m 22s W, generates 150 WPEP into an 8 dBi gain vertical antenna, while the mobile receiver uses a Ham-stick. Three data formats for 50, 100, and 200 kHz channels are being tested, with encoded data rates of 96, 192, and 384 kbps. Verilog code for the VHF OFDM modem is 95% simulated, with modifications from the UHF version including increased filter coefficient precision and a change from Ungerboeck **TCM** to BICM for improved performance over fading paths. Final tests will involve one-way over-the-air measurements of bit error rates and coverage area.

PACTOR mode radio modems and accessories, performance sailing electronics and innovative hard to find parts. Audio cables, packet cables, usb to serial converters

Q15X25 is a packet modem with a KISS/AX.25 interface designed for HF transmission of AX.25 packets and TCP/IP using Automatic Repeat reQuest (ARQ) and forward error correction (FEC).

Modem Telephone Super Filters For HF and AM Radio Interference.

DataBridge wireless RF modem modules facilitate point-to-point data transmission, supporting analog, digital, and serial RS232 UART signals. These modules are engineered for robust wireless communication, offering a reliable solution for various industrial and amateur radio applications requiring secure data links. The product line includes specific models designed for different frequency ranges and power outputs, ensuring compatibility with diverse operational requirements. Each module integrates advanced RF technology to maintain signal integrity over distance, crucial for remote monitoring and control systems. The design emphasizes ease of integration, allowing users to quickly deploy wireless data links without extensive configuration. Key features encompass low power consumption and a compact form factor, making them suitable for embedded systems and portable devices.

VARA HF is a soundcard modem that can be found on the HF bands exchanging traffic (Winlink). VARA implements an High Speed Data Mode and comes in 2 separate programs VARA FM and VARA HF. VARA is a High Performance HF modem based on OFDM modulation. VARA Modem, brings state of the art Military grade technology to new and existing HF data. Introduces a new standard of technology available for Amateur and Commercial use. Designed for operation within a SSB Bandwidth of 2400 Hz.

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.

This page, authored by VU2ESE, delves into the sBitx, a Software-Defined Radio (SDR) designed for homebrewers. The content covers the hybrid SDR circuit, software, user interface, hacking/modifying the sBitx, performance, and more. It explores the various components of the sBitx, including the exciter, filters, amplifiers, digital circuit, and modems. The page aims to provide information and guidance for hams interested in building their own SDR. Readers will learn about the capabilities, features, and adaptability of the sBitx, making it a valuable resource for DIY radio enthusiasts.

This blog post documents the author's journey building an APRS micromodem for amateur radio applications. Using an open-source design by LY2EN, the author assembled a cost-effective Terminal Node Controller (TNC) with SMD components, an Arduino Nano, and a JDY-31 Bluetooth module. The construction process included PCB fabrication, careful component soldering, microcontroller programming, and Bluetooth configuration. A custom 3D-printed case protected the completed device. Field testing in Romania showed the device functioned with a Baofeng UV-5R radio, though antenna limitations affected performance. The entire project demonstrates an affordable DIY alternative to commercial APRS trackers.

The N7YG Digital Engine, functions as a streamlined digital modem, supporting **PSK**, **RTTY**, and **MFSK** modes. It eliminates many ancillary logging and awards features found in other software, focusing instead on providing a dedicated digital interface. The software is specifically engineered to complement the N3FJP logging suite, offering a simple digital modem with a floating waterfall display that can coexist on the same screen as the logger. The application includes support for PSK Reporter, EXTFSK, TinyFSK, and K1EL Winkey FSK, enhancing its utility for various digital operations. Key features comprise a separate waterfall window, a main GUI with operational controls, receive and transmit display areas, and 10 Macro Buttons across 10 user-definable macro banks, totaling 100 macros for general and contesting use. Configuration options include sound card selection, digital gain (0-32767), AFC Level (0-100), AFC Width (in Hz), and COM Port TX keying for VOX/SignaLink or direct port control. Input and Output Mixer buttons provide direct access to OS audio mixer controls for precise level adjustments. The software is digitally signed with a security certificate, aiming to prevent conflicts with antivirus programs.