RF Toolbox is an antenna design and electronics/electrical tool package for Windows and Macintosh. It takes you step by step through the design of the many types of antennas, as well as numerous radio and electronic calculations.

More information, as well as downloads, can be found here:

http://www.blackcatsystems.com/software/electronics-antenna-design-software.htmlAntennas:

Dipole

Fat Dipole

Yagi

Long Yagi

J-Pole

Super J-Pole

Log Periodic

Cubic Quad

Vertical 1/8, 1/4, 3/8, 1/2, 5/8, 3/4, 7/8, and full wave

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

Zender Diode Calculator

Parallel Line / Ladder line Calculator