(Butler 1991) gives a design for a Small Transmitting Loop (STL) for 14MHz and some other bands.

He gives key design data:

```
``````
Tube Diameter d 0.75 inch
Circumference S 12.7 feet
Area A = 10 square feet
Frequency f = 14.2MHz
Power P 100 watts
Radiation Resistance Rr = 0.137 ohm
Loss Resistance RL = 0.064 ohm
Efficiency n = 68%
Inductance L = 3.27 micro-henry
Q factor = 723
Inductive reactance XL = 291 ohms
Bandwidth B = 19.6kHz
Distributed capacity Cd = 10.4pF
Capacitor potential Vc = 4587V
Tuning capacitor Ct = 28pF
```

The data above appear to ignore some important factors, and estimate some others based on an assumption of uniform current. Continue reading An NEC-4.2 model of VK5BR’s 1m square loop for 20m