If you’ve set up Winlink recently, you’ve almost certainly installed VARA, even if you weren’t entirely sure what it was doing behind the scenes. It’s the software modem responsible for actually getting your email-over-radio message from your station to a gateway, and it’s become the default choice for most Winlink users.
A software modem, not a piece of hardware
VARA is a soundcard-based software modem developed by Jose Alberto Nieto Ros, EA5HVK, that handles modulation, demodulation, and error correction for Winlink connections. It comes in two flavors: VARA HF, tuned for the noisier, lower-bandwidth conditions of HF propagation, and VARA FM, built for faster, cleaner VHF and UHF links where you can push much higher data rates. Both run as a background service that Winlink Express or other client software connects to.
Free version vs licensed version
VARA is free to download and use, but the free version caps your data rate well below what a paid license unlocks. Most casual Winlink users get by fine on the free tier, especially for short text messages, but anyone regularly moving larger attachments or operating in genuinely poor conditions will notice the difference a license makes. It’s a reasonable one-time cost if Winlink is a real part of your comms plan rather than something you set up once and forget about.
How it stacks up against ARDOP
ARDOP is Winlink’s other major modem option, and it’s fully open source where VARA isn’t, but VARA has generally pulled ahead in real-world throughput and reliability, which is a big part of why it’s become the default recommendation for new Winlink setups. I’d start with VARA for most home or portable Winlink setups, and only look at ARDOP specifically if the closed-source nature of VARA is a dealbreaker for you.
Related reading: ARDOP vs VARA · VarAC · Pat Winlink Client