Web Calculators for Ham Radio Projects
ik2nbu @ gmail.com
Ham Radio Life Style
This is my  short list of preferred web calculators that i use frequently to make fast RF and simple on line circuit simulations:

http://www.changpuak.ch/electronics/index.php
http://coil32.net/online-calculators.html
http://www.claredot.net/it/sez_Elettronica/elettronica.php
http://tonnesoftware.com/index.html
http://www.daycounter.com/Calculators/

We can make a comparison between the calculators, to be sure of schematic RF values results, but littles differences are normal and  will be corrected during pratical construction.
You must consider almost a 5 % of tollerance in RF value and, above all, use only a right selection of electronic components.
  Utility Software for Ham Radio Download Zip File:
I used this software programs for several goals: projects of circuits, filters calculator, differents design antennas etc. they are in Zip files and most of them have a help menu in English language, the old DOS version is ARRL free programs 90ys.
This software is easy to use and run also in WIN PC without trouble. You can also find simple Excell Calculator and in most programs you can print and save the results of calculation. The following links go directly to my public folders on Google Drive.
Amitor Coil on Toroids SWL OM Antenna BEAMS ANTENNAS LC Parallel Calc Delta Lops Antenna Quad Design
Wire Horizontal Lops Magnetic Lop Antenna Rectangular Lops Tube P Greco RF SIM DESIGN SPIRAL LOPS
ARRL Band Filters Coax Cable Traps Vertical Helical Antenna Short vertical Antenna Load Vertical Vertical short Quarter