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2.1. Antenna length based on the following formulars: 1/2 λ dipole (feet)= 468 / frequency in Mhz. 1/2 λ dipole (meters) = 142.65 / frequency in Mhz. Full wave loop (feet) = 1005 / frequency in Mhz. Full wave loop (meters) = 306.32 / frequency in Mhz. Cut wire slightly longer for connecting insulators and pruning. 22-Jun-2007 09:30 AM.
19 sty 2017 · I want to use an end-fed wire antenna, but what would be the best length of wire for the 20m and 40m bands? Is there a way to work this out? This is assuming a tuner will be used.
The impedance of a end fed wire can be anywhere from a few 10s of Ohms to a few thousand Ohms, depending on the frequency in use and the length of the wire. Other factors that can affect the impedance are bends in the wire, height above ground, proximity to buildings and wire diameter.
This calculator is an aid for determining antenna element lengths, based on Frequency, Type (Wire or Tubing), and Diameter (AWG#, inches, mm) of the element. At the top of the calculator, enter the Frequency (1 to 30 MHz) of interest.
SWR for all lengths should typically be under 2.2:1 and in most cases will be under 1.8:1 for 160-10m which will allow most built in ATU’s to match the antenna on all bands. Initial installation should utilize a
ARRL and HF Kits offer a 4-band antenna kit: End Fed Half Wavelength Antenna. The advantage of an EFHW is the ease of construction, it’s versatility in a variety of installation configurations, no tuner is needed, and this one works on 4 bands: 10, 15, 20, and 40 meters.
Figure 2 shows the complete schematic view of a typical EFHW antenna system. Briefly, the 100pf/2kv cap across the primary of the impedance matching transformer is there to allow better tuning in the 10 meter band. The transformer is a step-up with an impedance ratio of 49:1, and wound on a type 43 toroid core.
