RF ToolBox

RF Toolbox is an antenna design and electronics/electrical tool package. It takes you step by step through the design of the following types of antennas:
Dipole
Fat Dipole
Yagi
Long Yagi
J-Pole
Super J-Pole
Log Periodic
Cubic Quad
Vertical
Helical

It also performs the following calculations:

Transmission Line Calculator
Coil Design
LC Filter Design
Transmission Line Loss
L Matching Networks
Pi Matching Networks
Impedance Calculations
Wire Gauge and Resistance and Voltage Drop
Wire Inductance Calculations
dB Calculations
Resistor Series/Parallel Calculations
Resistor Color Code Calculations
Low and High Pass Butterworth and Chebyshev Filter Design
Thermal Noise Calculator
Pi Network Attenuator Calculator
Tee Network Attenuator Calculator
555 Timer Oscillator Calculator
RF Link Budget Calculator
Gamma Match Calculator
Skin Depth Calculator

With the transmission line calculator, you can select the type of line, length, operating frequency, and calculate the losses, as well as the SWR and losses from SWR due to impedance mismatch. The load impedance can also be calculated from the measured impedance at the line input.