Amitor Coil on Toroids SWL OM Antenna
Wire Horizontal Lops Magnetic Lop Antenna
ARRL Band Filters Coax Cable Traps
Rectangular Lops Tube P Greco
Helical Antenna Short vertical Antenna
Delta Lops Antenna RF SIM DESIGN
Load Vertical Quad Design
SPIRAL LOPS Vertical short Quarter
This is my  short list of preferred web calculators that i use frequently to make fast RF and simple on line circuit simulations:

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.