Elecraft Power Combo CLI (EPCC)

A Python Textual TUI application for combined control of Elecraft KPA500 amplifier and KAT500 antenna tuner via serial ports.

Design Philosophy

The KPA500 and KAT500 are treated as a single "combo" unit:

• Combined power control: Power button turns both devices on/off together
• Synchronized state: If one device is powered on at startup, the other is automatically powered on
• Continuous monitoring: Connected devices are polled regularly while powered on

Project Structure

src/
├── epcc.py      # Main TUI application with custom widgets
├── epcc.tcss    # Textual CSS styling (theming)
├── kpa500.py    # KPA500 async serial interface module
├── kat500.py    # KAT500 async serial interface module
└── model.py     # Application model bridging TUI and hardware
tests/
├── conftest.py         # pytest configuration with CLI options
├── test_kpa500.py      # Unit tests for KPA500 module
├── test_kat500.py      # Unit tests for KAT500 module
├── kpa500_live_test.py # Live hardware integration tests
└── kat500_live_test.py # Live hardware integration tests

Technology Stack

Component	Details
Python	3.12+
Textual	TUI framework
Rich	Terminal formatting
pyserial-asyncio-fast	Async serial communication
pytest	Testing framework
pytest-asyncio	Async test support

Features

KPA500 Amplifier Control

• Power on/off (supports bootloader mode wake-up)
• Standby/Operate mode switching
• Real-time monitoring: Power (W), SWR, Temperature, Current, HV, Band
• Fault detection and clearing

KAT500 Antenna Tuner Control

• Auto/Manual/Bypass mode switching
• Antenna selection (1/2/3)
• Full tune with automatic KPA500 standby
• Real-time monitoring: SWR, Bypass SWR, Forward/Reflected power
• Fault detection and clearing

Combined Features

• Unified power button controls both devices
• Segmented bar graphs with color thresholds for Power and SWR (KPA and KAT)
• Shared fault indicator with per-device fault text
• Tune button: puts KPA in standby, initiates KAT full tune
• Fixed KPA and KAT polling intervals; the KAT is not dynamically polled based on transmit state

Environment Setup

This project requires Python 3.12 or newer. Use an isolated environment rather than installing dependencies globally.

Recommended: uv

If you have uv installed, install the project and development dependencies from pyproject.toml:

uv sync --extra dev

Run commands through uv run so they use the managed environment:

uv run python src/epcc.py --kpa-port /dev/ttyUSB0 --kat-port /dev/ttyUSB1
uv run pytest tests/ -v

Alternative: venv + pip

python3.12 -m venv .venv
source .venv/bin/activate
python -m pip install --upgrade pip
python -m pip install -e ".[dev]"

After activating the virtual environment, run Python and pytest normally.

How to Run

# Run with both devices
python src/epcc.py --kpa-port /dev/ttyUSB0 --kat-port /dev/ttyUSB1

# Run with KPA500 only
python src/epcc.py --kpa-port /dev/ttyUSB0

# Run with KAT500 only
python src/epcc.py --kat-port /dev/ttyUSB1

# Custom baud rate (default: 38400)
python src/epcc.py --kpa-port /dev/ttyUSB0 --kat-port /dev/ttyUSB1 --baudrate 38400

# Custom fixed poll intervals
python src/epcc.py --kpa-port /dev/ttyUSB0 --kat-port /dev/ttyUSB1 \
    --kpa-poll-interval 0.25 \
    --kat-poll-interval 0.25

Command Line Options

Option	Short	Default	Description
--kpa-port	-k	None	KPA500 serial port
--kat-port	-t	None	KAT500 serial port
--baudrate	-b	38400	Serial baud rate
--kpa-poll-interval		0.25	KPA500 poll interval (seconds)
--kat-poll-interval		0.25	KAT500 poll interval (seconds)

Keyboard shortcuts:

Key	Action
h	Toggle help
p	Toggle power
t	Full tune
o	KPA operate
s	KPA standby
a	KAT auto mode
m	KAT manual mode
b	KAT bypass mode
1	Select antenna 1
2	Select antenna 2
3	Select antenna 3
Ctrl-Q	Quit

Testing

Unit Tests

Run the full test suite (no hardware required):

# With uv
uv run pytest tests/ -v

# Or inside an activated venv
pytest tests/ -v

Live Hardware Tests

Run integration tests with actual hardware:

# KPA500 live tests
pytest tests/kpa500_live_test.py --serial-port /dev/ttyUSB0 -v

# KAT500 live tests
pytest tests/kat500_live_test.py --serial-port /dev/ttyUSB1 -v

# Custom baud rate
pytest tests/kpa500_live_test.py --serial-port /dev/ttyUSB0 --baudrate 38400

Live tests are skipped automatically if --serial-port is not provided.

UI Layout

┌─────────────────────────────────────────────────────────────────────┐
│               Elecraft Power Combo (KPA/KAT500)                     │
├────────────────────┬────────────────────────────────────────────────┤
│  Power: 350W       │  KPA Mode:                                     │
│  Temp: 45°C        │  ○ Standby  ● Operate                          │
│  Current: 12.5A    │  KAT Mode:                                     │
│  HV: 53.2V         │  ● Auto  ○ Manual  ○ Bypass                    │
│  Band: 20M         │  Antenna:                                      │
│  FWD: 1234         │  ● 1  ○ 2  ○ 3                                 │
│  RFL: 56           │                                                │
│  Bypass SWR: 1.05  │  Power   ████████████░░░░░░░░░░░░░░░░░░ 350    │
│                    │  KPA SWR ██████░░░░░░░░░░░░░░░░░░░░░░░░ 1.3    │
│                    │  KAT SWR ████░░░░░░░░░░░░░░░░░░░░░░░░░░ 1.1    │
│                    │                                                │
│                    │  [ POWER ]  [ TUNE ]                           │
├────────────────────┴────────────────────────────────────────────────┤
│  [ FAULT ]  KPA Fault: None                                         │
│             KAT Fault: None                                         │
└─────────────────────────────────────────────────────────────────────┘
                              h: help

• Readings panel (left): Yellow background when powered on, dark when off
• Power bar graph: Green (0-500W), yellow (500-600W), red (600-700W)
• SWR bar graphs: Green (1.0-1.5), yellow (1.5-2.0), red (2.0-3.0)
  • Bar clamps at 3.0 but displays actual value if higher
• Radio buttons: Dark green when inactive, bright green when active
• Power button: Dark green when off, bright green when on
• Tune button: White on black normally, inverts while tuning
• Fault button: Dark red normally, bright red when fault active (click to clear)

Serial Protocols

KPA500 Commands

Commands use ^ prefix (e.g., ^ON;):

Command	Description
^ON;	Get/set power state
^OS;	Get/set operating mode (Standby/Operate)
^BN;	Get/set band
^WS;	Get power (W) and SWR
^TM;	Get temperature
^VI;	Get voltage and current
^FL;	Get/clear fault code

When KPA500 is in bootloader mode (powered off), send P to power on, then poll until responsive.

KAT500 Commands

Commands have no prefix (e.g., PS;):

Command	Description
PS;	Get/set power state
MD;	Get/set mode (Auto/Manual/Bypass)
AN;	Get/set antenna
FT;	Initiate full tune
TP;	Get tuning in progress status
VSWR;	Get VSWR
VSWRB;	Get bypass VSWR
VFWD;	Get forward voltage
VRFL;	Get reflected voltage
FLT;	Get fault code
FLTC;	Clear fault