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27 Φεβ 2021 · Antenna length being 1/2 and 1/4 wavelength means that the actual electric and magnetic fields can satisfy suitable boundary conditions that allow effective radiation and reception, arising from the mathematical structure of the fields. 1/3 or 1/8 wavelength corresponds to neither the nodes nor the maxima of a sinusoid. @nanofarad Minor quibble.
If you find the wavelength for the given frequency, then just find the type of antenna (quarter-wave), take the appropriate fraction of the wavelength, and convert said quantity to the appropriate units.
represent a square root, such as 4 = 2. If there is a superscript number in front of the radical sign, then it represents the root indicated. 3 8 =2 Ratio—A fraction, with one quantity divided by another. The value of π is the ratio of the circumference
26 Φεβ 2017 · Antenna length goes hand in hand with the frequency you desire to transmit on. The higher the frequency, the shorter the wavelength. Most commercially available antennas come in length equivalent from 1/4 to 5/8’s of a full wavelength.
5 Ιουν 2021 · Here is a simple antenna calculator for two popular forms of ham radio HF wire antennas: the horizontal dipole and the inverted "V". Enter your desired frequency (MHz) of operation (i.e. 3.55). If you have no particular preference within a given ham radio band, then simply enter its center frequency (i.e. 7.15 for the 40 meter band).
dB values. For example, to calculate the dB for a power ratio of 10/4 (2.5), subtract . the dB equivalents for 10 and 4: 10 – 6 = 4 dB. Similarly for a ratio of 10/2 (5), 10 – 3 = 7 dB. The ratio of 5/4 (1.25) is 7 – 6 = 1 dB and so forth. The same trick can be used with the voltage ratios. Copyright © 2013, American Radio Relay League, Inc.
15 Μαΐ 2018 · The formula 234/f is a handy way to estimate the size of a ¼ wave antenna element based on the desired frequency for the antenna. Here is how to derive that number using only other constants and conversion ratios.
