Var-Ac HF Digital

About VarAC

VarAC and VARA: Keyboard Chat for the Modern Radio Amateur

VarAC is a free, modern chat and emergency communications (EmComm) application for amateur radio. It brings real-time, keyboard-to-keyboard QSOs back to the bands, and works on HF, VHF/UHF FM and satellite. It was written by Irad Deutsch, 4Z1AC, and feels much more like a modern messaging app than an old packet terminal.
You can call CQ, chat one-to-one, join group broadcast rooms, leave messages for stations that aren’t on the air, send files, and see signal reports and recently heard stations. Small touches like a “typing” indicator and emojis sent over RF make conversations feel natural, even across thousands of miles of HF.

The engine behind VarAC is VARA, a high-performance soundcard modem developed by Jose Alberto Nieto Ros, EA5HVK. VARA uses OFDM, the same family of waveforms used in Wi-Fi and digital broadcasting. It adapts its speed in real time as band conditions change, so a link stays up through fading and noise. Its weak-signal performance is often compared to FT8, but it carries a proper two-way connection with error correction rather than short fixed messages.

VARA comes in two versions. VARA HF is for SSB transceivers and runs in 500 Hz or 2,300 Hz bandwidths, at up to about 7,000 bps. VARA FM is for VHF/UHF FM radios and reaches well over 12,000 bps. VARA is also widely used by Winlink, so if you already run Winlink over VARA, you’re halfway to using VarAC.

All you need is a transceiver with a built-in USB soundcard (such as the IC-7300) or an external interface like a SignaLink or DigiRig, plus a Windows PC. VARA is shareware: it’s free to try, and a one-off licence unlocks full speed on HF.

VARA (Virtual Audio Radio) modem is a proprietary software application designed for use by radio amateurs. The software provides a range of features for radio operators, including the ability to send and receive data over radio frequencies using soundcard-based digital modes.

One of the key features of VARA modem is its support for high-speed data transmission. The software is capable of transmitting data at rates of up to 7,200 bits per second, which is significantly faster than many other digital modes used by radio amateurs. This makes VARA modem a valuable tool for operators who want to transmit large amounts of data quickly and efficiently.

Another important feature of VARA modem is its reliability. The software includes advanced error-correction techniques, which can help to ensure that data is transmitted accurately and reliably even in the presence of noise and interference. This means that radio operators can trust VARA modem to transmit their data effectively, even in challenging conditions.
VARA modem also includes a range of tools for managing connections and optimising performance.

It is specifically tailored to Emergency Communications also. Running on a Laptop and using a QMX+ for eg. Other 5-10W radio's too Icom and Yeasu.

The software includes a built-in connection manager, which can be used to establish and maintain connections with other operators using VARA modem. The software also includes features for adjusting audio levels and optimizing signal strength, which can help to improve the quality of transmitted data.

One of the unique features of VARA modem is its support for automatic message forwarding and Email. The software can automatically forward messages and Email to other stations and people, based on a set of predefined rules. This feature can be particularly useful for emergency communications, as it allows operators to quickly and efficiently relay messages to other stations without the need for manual intervention.

Overall, VARA modem is a powerful and reliable software application for radio amateurs. With its support for high-speed data transmission, advanced error-correction techniques, and automatic message forwarding, VARA modem is a valuable tool for any operator who wants to transmit data quickly and reliably over radio frequencies. Whether you're communicating with other operators for fun or participating in emergency communications, VARA modem is a versatile and powerful tool that can help you get the job done effectively.

Many radios supported including by Omni-Rig and Flrig. I use the latter.
Be aware! As with any digital communication on your radio, it is wise to run the power level at 50% or below. The PA would benefit from not being driven at the full duty cycle and save your PA.
If you have a linear amp however, you can run that at 50% to get that extra mile or two :)

As a tip, you can run two instances of Vara and configure one as transmit and one as a receive decoder.
Why not have a look on the web, Google Vara and VarAC for complete details. I suggest you (RTFM) and look at the etiquette guide.

HF or VHF Digital Coms Vara & VarAc

About VarAC