GARC HAM Labs

Interactive educational tools for amateur radio operators — from first-time learners to seasoned hams

Available Labs

Select a lab to begin training. New labs added regularly.

⚡

CW Trainer

All Levels

Learn CW from scratch with a realistic straight key simulator. Progressive lessons from basic dits and dahs through full alphabet, numbers, and common phrases. Real-time timing analysis and feedback.
📡

Propagation Simulator

Intermediate

Visualize HF propagation paths and understand how ionospheric conditions affect signal reach. Interactive layers, ray tracing, and solar index simulation.
🔧

Antenna Designer

Intermediate

Calculate precise antenna dimensions for any frequency. Dipoles, verticals, loops, and more using standard ARRL formulas. Real measurements in feet and meters.

Morse Code Trainer

Press the key to practice. Supports keyboard input and USB hardware keys (Chrome/Edge).

Trainer Power
OFF
WebHID Available
⌨️ Keyboard

Morse Code Reference

▼
A
.-
B
-...
C
-.-.
D
-..
E
.
F
..-.
G
--.
H
....
I
..
J
.---
K
-.-
L
.-..
M
--
N
-.
O
---
P
.--.
Q
--.-
R
.-.
S
...
T
-
U
..-
V
...-
W
.--
X
-..-
Y
-.--
Z
--..
0
-----
1
.----
2
..---
3
...--
4
....-
5
.....
6
-....
7
--...
8
---..
9
----.
Straight Key
Ctrl Space Enter to key • Click/Tap key graphic
Waveform
Live Decoder
Pattern
—
Character
—
Message
—
Settings
Timing Analysis
Avg Dit
— ms
Avg Dah
— ms
Dit:Dah Ratio
—
Consistency
— %
Start keying to see timing feedback

Lesson Progression

E T
The simplest Morse characters: E (dit) and T (dah). Master these before moving on.
0 / 10 correct

Antenna Designer

Calculate precise antenna dimensions using standard amateur radio formulas

Configuration
MHz

Calculated Dimensions

Total Length
33.02 ft
Each Leg
16.51 ft
Wavelength
69.39 ft
Min Height
17.35 ft
Antenna Diagram
Feed Point (50Ω) ← Leg 1 → ← Leg 2 →

SWR Curve

Rr: 73Ω
Q: 11.7
2:1 BW: 600 kHz
Min SWR: 1.46:1
1:11.5:12:12.5:13:13.5:14:113.42613.72514.02514.32514.62514.924Frequency (MHz)SWRf₀ = 14.175 MHz1.46:1
SWR vs Frequency
2:1 SWR Bandwidth
2:1 SWR Threshold
Formula Used
Length (ft) = 468 ÷ f(MHz)
Standard half-wave dipole formula with 0.95 velocity factor
Design Notes
  • 📌 Cut wire slightly long (add 2-3%) and trim to tune
  • 📌 Height affects impedance and radiation pattern
  • 📌 Use a 1:1 balun at feed point to reduce common-mode currents
  • 📌 At λ/2 height, pattern is mostly horizontal
  • 📌 Insulated wire requires slightly shorter lengths (~3%)

Propagation Simulator

Visualize ionospheric propagation and understand how solar conditions affect HF bands

Ionosphere Cross-Section
F2 Layer 268km F1 Layer 175km E Layer 110km D Layer 74km Skip Zone TX RX 15°
D Layer (60-90km)
E Layer (100-120km)
F1 Layer (150-200km)
F2 Layer (250-400km)
Frequency Limits
MUF (Max Usable)
22.5 MHz
LUF (Lowest Usable)
6.9 MHz
Skip Distance
2003 km
Max 1-Hop
3,698 km
Critical Freq
5.8 MHz
Band Conditions
160m
ABSORBED
80m
ABSORBED
60m
ABSORBED
40m
FAIR
30m
GOOD
20m
EXCEL
17m
GOOD
15m
FAIR
12m
DEAD
10m
DEAD
Time of Day (UTC)
12:00
Local Solar Time
☀️Daylight
Solar Conditions
SFI
120
SSN
50
K-Index
2
A-Index
8
Signal Path
What's Happening
☀️ Daytime Propagation
During daylight hours, the D-layer absorbs lower frequencies while the F2 layer provides the primary refraction path for DX. Mid-to-high HF bands (20m-10m) are most effective for long-distance contacts.