EH STAR (14 Mhz)

The critical dimensions for calculation (which determine its angle of radiation) are the cylinder diameter/length. The followings cylinder length/diameter ratios work well depending on the choice of band: 1,8 MHz - 215/110 mm. and more; 3,5 MHz - 110/75 mm. and more; 7 MHz - 75/50 mm. and more; 10 mhz - 50 mm. and more; 14 MHz - 50/32 and more; 18-28 MHz - 32-20 mm. and more; 145 MHz - 15/8 mm and more. The ratio length/diameter we choose range in ratio between 1-6. What anymore ratio length/diameter, or than anymore diameter of cylinder (there is length/diameter at unchanging ratio) - the anymore bar of key-in of antenna. Please play with the program and see how antenna parameters change before you construct your antennas. Also please note that in the program, a phasing coil in our flat EH antenna is not used, because it is not necessary to compensate for any stray capacity of the central wire that passes through the centre of the pipe (this is important however for the cylindrical variant of EH antenna). Please note that the flat EH antenna does not use a ‘source coil’ and this will be discussed on my tuning page. By the way, it is possible to enter data i.e. dimensions of cylinders, wires etc. based on what you have available because this is a big part of the fun in experimenting and playing with EH flat antennas. Suitable materials for constructing the rectangular plates include (besides copper plate itself), "copper foil fibreglass" or a "copper net".

The above describes how to derive the dimensions of flat EH antennas for the band of your choice. The next stage following construction is to tune the antenna itself. This is done by connecting the central wire from the middle of the SO239 to the first or second turn of the tuning coil. This is described in much more detail on my TUNING page.

http://www.flateh.narod.ru/construction.htm