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Program for amateur radio digital communications via a sound card. Supported modes are RTTY (Baudot code), ASCII (7 or 8 bits), PSK31 (BPSK and QPSK) and AMTOR-FEC (SITOR-B, NAVTEX). SELFEC SITOR decoding is possible also. No additional hardware required, need only a sound card. Optionally you can use simple circuit fo PTT-control. Can cooperate with RZ4AG AAlog logger.

Version 1.4.6 of _AAVoice_ functions as a digital voice processor for amateur radio, designed to operate on Windows platforms from 9x through 10. This software leverages pre-recorded WAV files for transmission, allowing operators to send pre-defined messages or calls efficiently. Its core functionality includes PTT control, which can be managed through a simple circuit connected to a COM port, providing a reliable interface for radio keying. The program offers extensive macro capabilities, streamlining repetitive transmissions during contesting or DXing. It also features direct integration with the _AALog_ logger, enhancing workflow for those using DXsoft's suite of tools, and can interface with other compatible programs via its COM-interface. Author Alexander Anipkin designed _AAVoice_ to require a working sound card, and it comes with a basic set of sound files. Users can easily create additional WAV files using standard Windows sound recording utilities, ensuring flexibility in customizing audio content for various operating scenarios.

Demonstrates building a basic _VOX circuit_ to add voice-operated transmit functionality to HF transceivers that lack this feature. The design utilizes a _1458 dual op-amp_ (two 741 op-amps in one package) to amplify microphone audio and act as a comparator, driving an NPN switching transistor for PTT control. A capacitor, C2, provides the necessary delay before unkeying the PTT, with a variable resistor, R6, allowing adjustment of the VOX level for specific microphones or voices. This low-cost circuit, detailed with a full parts list, offers a practical solution for hams seeking to enhance their budget HF rigs. The author, N1HFX, provides guidance on initial setup, including advice on microphone gain and the use of headphones to prevent speaker audio from re-keying the transceiver. Modifications for adjusting delay time are also included, suggesting increasing R8 to 10K for more delay or decreasing C2 to 22µF for less.

gMFSK, a Gnome Multimode HF Terminal, provides a comprehensive software solution for digital conversational modes on HF bands within Linux and Unix-like operating systems. The application facilitates sending and receiving various digital modes, including MFSK (MFSK16 and MFSK8), RTTY, THROB (1, 2, and 4 throbs/sec), PSK31 (BPSK and QPSK), PSK63, and MT63. It leverages the computer's soundcard for transceiver interfacing, performing all digital signal processing on the main CPU. The software features a multimode waterfall display incorporating waterfall, spectrum, and scope views, enabling _point-and-click tuning_ of decoded signals. Remote logging capabilities are supported via SysV IPC, with integration for logging applications like Xlog. PTT control is managed through serial or parallel port lines, and rig control is implemented using the _Hamlib_ library, allowing for real-time frequency display and transceiver manipulation. Fixtext macros can incorporate variables and command-line output. Distributed under the GNU General Public Licence, version 2, gMFSK requires Gnome libraries and FFTW 2.x libraries for operation, even without a full Gnome desktop environment. The software's design ensures compatibility with any soundcard supported by the operating system.

Sells leading-edge voice and digital communications products to the world-wide military, government, industrial, and amateur radio marketplaces. Bluetooth Remote Audio/PTT, Rig Controller with Audio & PTT , HamLinkUSB Rig Control, Noise filtersm antenna analyzers, Multimode Data Controller, TNC, Packet Radio Terminal Node Controller. USB2RS232

CwType v2.35 provides a dedicated terminal interface for **CW operators**, facilitating Morse code transmission from a Windows PC. Users can input characters via the keyboard or a connected paddle, supporting iambic keying. The software manages transceiver control, including PTT and CW keying, through COM or LPT ports. It offers adjustable speed, dash/dot ratio, and inter-letter spacing, with real-time speed display in LPM and WPM calculated by the "PARIS" method. The program includes features like MOX mode for automatic TX on/off, configurable weighting to compensate for transceiver element clipping, and programmable F-key macros for sending predefined text or special sequences. CwType can integrate with logging software such as AALog (V1.0.3 and later) for data transfer, and supports various character sets including English, Russian, and Swedish. A beacon mode is also available, executing the Alt-F12 macro periodically at a user-defined interval. Audio output for monitoring can be routed through the internal PC speaker or a sound card, with options for sine waveform and smooth envelope generation for SSB transmitters. The software is compatible with **Windows XP/Vista/7/8/10** and is distributed as freeware.

This online guide details the microphone pinout for the Kenwood TR-7950 transceiver, specifically addressing the wiring configuration for a dynamic mobile microphone with a **500 Ohm** impedance. It provides a pin-by-pin breakdown for the 6-pin microphone connector, identifying the function of each active pin. The resource specifies that Pin #1 is for the microphone audio (white wire), Pin #2 controls the _PTT_ (black wire), Pin #3 activates the memory down function (blue wire), and Pin #4 controls the memory up function (red wire). Pin #6 is designated as the ground connection, while Pin #5 remains unused in this configuration. The document focuses on the physical wiring necessary to restore microphone functionality to the Kenwood TR-7950, a transceiver capable of **45 watts** output on the _2m band_. It directly addresses the technical challenge of re-establishing correct electrical connections after microphone wires have been disconnected from the connector. The information facilitates proper microphone operation for simplex QSOs and other voice communications. DXZone Focus: Online Guide | Microphone Pinout | Kenwood TR-7950 | PTT Wiring

Hidden transmitter hunting, often called fox hunting or Amateur Radio Direction Finding (_ARDF_), presents a unique challenge for radio amateurs. This resource details the _PicCon_ controller, a specialized device designed to automate the transmission of signals for such events. It integrates with a standard radio transceiver, functioning similarly to a packet radio TNC, by controlling the Push-To-Talk (PTT) line and injecting audio tones or modulated CW Morse code into the microphone input. The _PicCon_ unit is field-programmable using DTMF tones received via the radio, storing all settings in EEPROM for power-off retention. Its compact design and low power consumption (a few milliamps from a 7-35VDC source) make it suitable for remote deployment. An onboard LED indicates operational status, and a push-button allows manual start/stop of transmissions without DTMF. Typically supplied as a kit, _PicCon_ includes a PCB, components, and a comprehensive manual (available in HTML, RTF, and PDF formats). The kit provides a six-conductor interface cable, but users must supply radio and power plugs due to varied configurations. Byon, _N6BG_, developed this controller, which is available from the Byonics website.

The Elecraft K2 transceiver requires specific modifications for optimal soundcard digital mode operation, particularly for PSK31. The original article, circa 2001, details initial challenges with manual PTT and speech compression settings. A key modification involves adding headphone audio and a compression disable signal to the K2's microphone jack, utilizing pins 4 and 5. The **COMP0** signal, active low, is shorted to ground via a non-inverting open collector switch circuit, comprising two resistors and two transistors, mounted on the SSB board near U3. This circuit provides effective control of an analog signal line with good noise immunity. The switchbox itself repurposes a computer COM port switch, using only two of its original connectors and four of the nine poles. It integrates a microphone preamplifier, a PTT circuit built with 'flying leads' construction, and RCA jacks for soundcard connections. A trimpot adjusts the audio drive to the K2. The central DB9 connector links to the K2's mic connector via a shielded RS232 serial cable, ensuring proper grounding and signal routing. An external footswitch PTT jack is also included. Further enhancements include a **noise-canceling microphone** preamp based on a QST December 2000 article, adapted for Heil mic elements. This preamp, built with pseudo-Manhattan style construction, provides a gain of approximately 2 by changing emitter resistors (R9 and R16) from 680 ohms to 330 ohms. A 10-ohm series resistor and 47 µF capacitor on the +5V supply mitigate noise spikes.

This document details the design and construction of the PA70H, a 50-watt RF amplifier for the 70MHz (4-meter) amateur radio band. Built around the Mitsubishi RD70HVF1 MOSFET transistor, the amplifier delivers 45-55W output with 3-5W input power while operating on 13.8V DC at approximately 7-8A. The PCB design incorporates multiple protection circuits including overcurrent, SWR, and temperature control. The amplifier features various control modes including GND PTT, +13.8V PTT, and RF VOX. Two versions are available: PA70HLI (requiring 100mW input with additional driver) and PA70H (for 3-5W input). The comprehensive documentation includes circuit diagrams, assembly instructions, and performance data showing successful operation from both 100mW and 3.5W input sources.

Explains the fundamental concepts of **PSK-31** digital mode, detailing its origins from phase shift keying and how it achieves a narrow 31 Hz bandwidth. George Rothbart, KF6VSG, demonstrates the signal's behavior on an oscilloscope, illustrating the 180-degree phase shifts that define its bit stream. The resource highlights PSK-31's superior signal-to-noise ratio compared to FSK, noting its 20 dB advantage over SSB, which enables reliable cross-country contacts with QRP power levels. It also delves into the unique **vericode** character encoding, which uses variable-length bit patterns to optimize data rate by assigning shorter codes to common characters, resulting in an average of 6.5 bits per character versus 10 for ASCII. The presentation concludes with practical guidance on assembling a PSK-31 station, outlining the necessary computer hardware, sound card, stable HF transceiver, and cabling, along with methods for PTT control via a COM port.

Translates CAT PTT commands into COM port DTR line changes. Use COM port PTT instead of CAT PTT control.

A DIY Automatic Band Decoder (ABD) project, designed for dual-radio operation, addresses the common challenge of integrating band data with older transceivers lacking dedicated outputs. This particular build utilizes an AVR AT90S8515 microcontroller and a 16x2 Liquid Crystal Display (LCD) to provide band information, specifically targeting Kenwood rigs via a computer's LPT port. The design aims for cost-effectiveness while maintaining functionality, offering a solution for hams seeking to add automatic band switching capabilities to their station without significant expense. The project outlines the core components required, including the microcontroller, LCD, and an enclosure, noting that the Printed Circuit Board (PCB) fabrication and AVR programming might present challenges for some builders. It details the input requirements, such as a four-pin input and PTT for each radio, along with a 13.8V DC power supply. The decoder provides 2x6 outputs capable of sinking 500mA, suitable for controlling external devices like antenna switches or filters. Despite the original unit being damaged by a lightning strike in 2004, the author confirms its successful operation prior to the incident and mentions plans for a revised version. The resource includes a schematic in PDF format and images of the finished PCB and assembled unit, demonstrating the practical implementation of the design.

The m0xpd keyer project utilizes a PIC16F628A microcontroller, offering Iambic A and B modes, adjustable speed from 5 to 40 WPM, and variable weight control. It incorporates a sidetone generator with adjustable frequency and volume, along with a PTT output for transceiver control. The design includes a 16-pin DIL IC socket for the PIC, a 3.5mm stereo jack for the paddle, and a 3.5mm mono jack for the PTT output. Powering the keyer requires a 9V DC supply, which is regulated down to 5V for the PIC. The circuit board layout is designed for through-hole components, facilitating home construction. A detailed schematic and a parts list are provided, guiding builders through the assembly process. The project also discusses the firmware programming for the PIC16F628A, essential for the keyer's functionality. Construction details cover component placement and wiring, ensuring proper operation. The keyer's compact size makes it suitable for portable or shack use, providing a reliable CW interface.

Constructing a digital interface for the Elecraft K2 transceiver, this resource details the "Fat Wire" design by WG4S. It demonstrates how to integrate a sound card for digital modes, outlining specific connections to the K2's microphone jack and internal audio path. The author shares practical insights from his build, including the use of _RG-62_ coax for its flexible braid and the strategic placement of components like the 2.2K resistor and _2N2222_ transistor. The guide provides a breakdown of the interface's internal wiring, specifying connections for AF In (pin 1), AF Out (pin 5), PTT (pin 2), and Ground (pin 7) on the K2's microphone connector. It also covers the external connections to a laptop's headphone and line-in jacks, along with a DB-9 connector for PTT control via _DTR_ or RTS lines. The author notes that his laptop's headphone output level was sufficient for the K2, negating the need for an attenuator. Reflecting on the design, the author, Dan WG4S, acknowledges a later suggestion to house the components directly within the DB-9 shell for a more compact build. This iterative feedback highlights the ongoing evolution of DIY ham radio projects and the community's collaborative spirit in refining designs.

This project is a USB Audio, Serial and PTT interface for rigs that does not directly support digital modes provided by applications such as FLDIGI, WSJT-X and JS8CALL. Plug these interface devices into your Windows or Linux laptop or Raspbian Raspberry Pi and you can send and receive digital tones to/from your rig and automate the frequency and mode control and PTT control.

A 15-pin data switch, typically a rotary-knob type designed for DB-25 connectors, forms the basis for this microphone selector project. The resource details the conversion process, which involves replacing the original DB-25 connectors with **RJ-45** or **RJ-12** jacks to accommodate modern amateur radio microphones. It specifically addresses wiring for radios like the Icom IC-706 series (including the IC-7000 and IC-703) and Yaesu transceivers such as the FT-857, FT-897, FT-817, FT-7800, FT-7900, FT-8800, FT-8900, FTM-100, and FTM-400. The design ensures all microphone lines are switched straight through, with separate contacts for external speaker/headphone jacks, allowing simultaneous switching. The project emphasizes the practical application of switching between a headset for net control and a hand mic for rag-chewing without repeatedly plugging and unplugging cables. It highlights modifications to the original concept, such as eliminating a separate PTT jack by integrating PTT into headset cables and building the external speaker cable directly into the selector. The article provides guidance on managing the non-color-coded wiring often found in these data switches by soldering wires one by one from old to new connectors, ensuring correct pin alignment. This approach simplifies the conversion, making it accessible for hams seeking a functional and cost-effective mic switching solution.

This interface includes both the CAT and the PTT circuits,and it can be controlled from a single COM port for the Yaesu FT-817 transceiver

The Aziloop DF-72 antenna system provides 72 K9AY headings and 36 loop axes, allowing for rapid switching in 60 ms. It integrates a switchable 18 dB preamp, a 4-step attenuator (0-18 dB), and four 7-pole preselection filters to optimize receiver performance. The K9AY load is adjustable from 250 Ohm to 950 Ohm in 50 Ohm increments, offering flexibility for various receiving conditions. Control is managed via an intuitive Windows UI, supporting Local, Client, or Server modes, with headless remote operation possible through the built-in Ethernet Server. _Omni-Rig_ support facilitates auto-filter selection, PTT muting, and Rig-Sync functionality, enhancing integration with existing station setups. Designed by _GW4GTE_, the system utilizes a low visual impact, small-footprint antenna with orthogonal loops and an earth connection. It is suitable for general monitoring, co-channel station resolution, basic direction finding, and interference reduction across the VLF to HF spectrum.

Beam Controller Interface Project. The control system will be via the internet and consist of a Rig-Expert WTI-1 interface which provides access to CAT commands, PTT, and Rx and Tx audio.

This project details an automatic roger beep circuit for VHF/UHF contests. Built around a Microchip PIC microcontroller, the design detects PTT (Push-To-Talk) activation and generates a brief tone upon release, mimicking a "roger beep" to signal the end of transmission. The circuit utilizes readily available components and includes downloadable resources for PCB layout and firmware.

This online project documentation details the construction of a hands-free microphone interface unit designed for _mobile_ amateur radio operation. The curriculum covers the integration of electret microphone elements with amateur radio transceivers, specifically addressing **VHF** band communication. It outlines the circuitry for a switch box that provides an interface between various radio models and microphone types. The guide specifies the inclusion of a **1750 Hz** tone-burst generator for accessing amateur radio repeaters, an operational protocol for many VHF systems. Design considerations include the reduction of ambient vehicle noise through an adjustable audio input level control. The project provides schematics and wiring diagrams for connecting the interface unit to specific amateur radio transceivers, including the Yaesu FT-817. It addresses the selection and adaptation of readily available electret microphone and earpiece assemblies, initially sourced from mobile phone accessories, and later from dedicated headset units. The design incorporates a control mechanism for radio functions, enabling hands-free operation during _mobile_ excursions. Circuit details cover power supply considerations for the electret microphone and signal routing for both transmit audio and received audio monitoring. The documentation specifies component selection for the switch box, ensuring compatibility with common amateur radio microphone input impedances and output levels. This includes considerations for PTT line switching and audio path isolation. DXZone Focus: Online Project Documentation | Hands-Free Mobile Microphone Interface | Electret Microphone Integration | 1750 Hz Tone-Burst Generation

INTERCOM is a freeware application designed for remote control of KENWOOD TMD700/710/V-71 transceivers, as well as other transceivers equipped with UP, DOWN, and PTT commands. Compatible with Windows XP and higher (32 & 64-bit), INTERCOM offers multilingual support in English and French, and can be used on Linux, Ubuntu, or Android platforms via WINE 1.0 or CROSSOVER. The software enables users to send basic commands—such as selecting TX, VFO, memory channels, or power levels—either through manual inputs or over a TCP/IP link. INTERCOM is tailored for SIMPLEX setups, facilitating the interconnection of VHF/UHF repeaters with nearby repeaters. Remote commands are transmitted using DTMF codes, which are decoded by SIMPLEX and forwarded to INTERCOM via TCP/IP. This functionality makes INTERCOM an ideal tool for radio enthusiasts and operators seeking seamless remote management of supported transceivers in simplex configurations.