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Morse code copy practice tool featuring a fully operational Enigma machine. Master CW decoding through realistic WW2 campaign missions and 100+ standalone challenges.
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KE9BOS
Ham Radio • Open Source • CW Enthusiast
Brett Hollifield — KE9BOS. Amateur radio operator from Indianapolis. I maintain the Vail Adapter open-source project and build tools to help people learn CW. When I'm not at the bench, I'm chasing POTA activations, riding motorcycles, or exploring somewhere new.
Current Projects
What I'm actively working on right now.
OnlyHams New
A real-time HF propagation map — see who you can hear right now from live RBN spots, POTA activators, and online CW operators. Includes rig CAT control and live chat.
Visit Site →Vail CW School New
A full Morse code learning platform — structured lessons, daily challenges, copy and send practice, progress tracking, and leaderboards.
Start Learning →Vail Repeater
Internet CW repeater for practicing Morse code with others worldwide in real-time.
Visit Site →Spark Watch New
A game where you copy authentic historical maritime distress signals — SOS and CQD — across difficulty levels, campaigns, and leaderboards.
Play Now →ReRBN New
A real-time Reverse Beacon Network spot aggregator with a searchable web interface and public REST API for live CW, RTTY, and FT8 spots.
Visit Site →Morse Mailbox
Asynchronous CW messaging platform — send and receive Morse code messages to other operators. Currently in open testing.
Visit Site →Morse Story Time New
Listen to stories transmitted in Morse code at adjustable speeds, take notes, and answer comprehension questions across difficulty levels.
Visit Site →Ben's Best Bent Wire New
A fast-paced Morse code speed-challenge game with Firebase leaderboards and multi-keyer support.
Play Now →Vail Zoomer New
A cross-platform desktop app that mixes CW sidetone into your microphone — send Morse code during Zoom, Teams, and Discord calls.
Download →CW Training Tools
Browser-based tools for learning and practicing Morse code at your own pace.
Start Training →Xenomorse
A roguelike RPG that teaches Morse code as you play. Learn CW through gameplay, not drills.
In DevelopmentVail Summit Device
A Morserino-style standalone CW device with a 4" display and built-in mini keyboard. Features games, training tracks, online repeater access, Morse Mailbox integration, and more.
Beta TestingVail Adapter Improvements
Ongoing firmware and hardware updates to the open-source zero-delay Morse code USB interface I maintain.
View on GitHub →YouTube Channel
Prepping video content covering CW, ham radio, and the Vail ecosystem of products.
Subscribe →Products & Shop
Hardware I design and sell — order direct from the official store at shop.ke9bos.com.
Vail Adapter
A zero-delay Morse code USB interface that solves computer audio latency for CW practice. Works with MIDI, keyboard input, and direct radio keying. I took over maintenance and development of this open-source project and sell official assembled units and kits.
Vail Summit Beta
A Morserino-style standalone CW device — no computer required. Features a large 4" display, built-in mini keyboard, and a ton of functionality:
- CW training classes and structured learning tracks
- Games for building speed and accuracy
- Online repeater access via WiFi
- Morse Mailbox integration
- Radio control for on-air operation
- Multiple WiFi modes
Official KE9BOS Store
The official store for Vail Adapters, assembled units, kits, and CW accessories. Buy direct — this is the only official source for genuine hardware.
Shop at shop.ke9bos.com →On the Air
Ham radio activity and community involvement.
POTA Activations
Parks on the Air — I activate parks regularly. Look me up on pota.app.
Volunteer Operations
Public event support including marathon communications.
Other Builds
Hardware and embedded experiments away from the CW bench — 3D printing, PCB design, and microcontrollers.
OpenDisc
An open-source disc golf throw analyzer — a small ESP32-C6 puck with a high-G IMU that measures spin rate, release speed, and hyzer/nose/launch angles.
In DevelopmentSplit-Flap Display
A modular 3D-printed split-flap display with stepper-driven character drums and ESP32-C3 controllers networked over ESP-NOW.
PrototypeWiFi Flip Clock
An ESP32 servo-driven flip-digit clock and counter with NTP sync, RTC fallback, and an embedded web configuration UI.
CompleteGRV Groovebox
An OP-1–inspired portable groovebox — a Flutter touchscreen UI on a Raspberry Pi backed by a C++/JUCE audio engine.
In DevelopmentQuadruped Robot
A four-legged walking robot with expressive OLED eyes, eight servos, and an ESP32-S3 camera controller running custom gait code.
In DevelopmentESP32 Drone Synth
A generative ambient drone synthesizer on an ESP32 using the Mozzi library, with five modes and rotary/OLED control.
PrototypeAbout
I'm Brett, KE9BOS — an amateur radio operator and maker based in Indianapolis. I got into ham radio for the technical challenge and stayed for the CW.
I took over maintenance of the Vail Adapter project from its original creator and have been expanding it ever since — improving the hardware, adding features, and building out a whole ecosystem of tools for CW practice and training. What started as helping with an open-source project has grown into a community of contributors and users worldwide.
Beyond radio, I'm into 3D printing, PCB design, and open-source hardware. I believe in building things that are useful, well-documented, and accessible to others who want to learn or contribute.
When I'm away from the workbench, you'll find me on a motorcycle, mountain biking, traveling somewhere new, or hunting down good food.
Contact
I love collaborating with other hams and makers — whether it's bouncing ideas around, helping troubleshoot a project, or just talking shop. I'm also always happy to hear feedback on the tools and hardware I build. If something's working great or could be better, let me know.