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--- hf:antennas [2024/01/21 20:09] – m0tzo
+++ hf:antennas [2024/01/23 18:47] (current) – m0lte
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 Dipoles are band specific.
-{{:hf:dipole_image.gif?400|}}
+{{:hf:dipole_image.gif}}
-===== Good Resources =====
+==== Good Resources ====
 https://www.hamradiodx.net/beginner-hf-antennas\\
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 ===== The Loop=====
-The Amateur Radio HF Loop is an antenna design used in amateur radio for transmitting and receiving high-frequency (HF) signals. It is characterized by a loop-shaped conductive element, and there are various types, including magnetic loops and electric loops. Magnetic loops often employ a resonant loop of wire with a variable capacitor for tuning, while electric loops may consist of a full loop or a small section of a loop with a capacitor for tuning.
+The Amateur Radio HF Loop is an antenna design used in amateur radio for transmitting and receiving high-frequency (HF) signals. It is characterized by a loop-shaped conductive element, and there are various types, including magnetic loops and electric loops. Magnetic loops often employ a resonant loop of wire with a variable capacitor for tuning, while electric loops may consist of a full loop which can be very large to very small or a small section of a loop with a capacitor for tuning.
 HF loops are popular among amateur radio operators for several reasons. They can be compact, making them suitable for situations with limited space. Additionally, they can exhibit directional characteristics, allowing operators to focus their signal in specific directions. HF loops are often used in portable or temporary setups and can provide efficient performance when tuned properly. The tuning process is crucial to achieving resonance and optimizing performance on a specific HF frequency.
+===== The Full Wave Loop=====
+Definition
+A full wave loop is, as the words imply, a continuous loop of wire or other conductor approximately one wavelength long, usually with the two ends of the loop connected to the feedline.
+The exact length for resonance depends on the diameter of the conductor and the shape of the loop, but typically it is slightly longer than a physical half wavelength at the resonant frequency. A traditional formula for the length in meters is 306 / MHz (or 1005 / MHz in feet), but, like the similar formula for a dipole, this must be considered only an approximation. Unlike dipoles, larger diameter conductors require a larger circumference for resonance.
+Full Wave Loop Characteristics
+The full wave loop forms a second basic building block of antennas, along with the the half wave dipole. In fact, the two are similar in many ways: the full wave loop can be thought of two dipoles with the ends connected together, or a folded dipole opened up into a 2-dimensional shape.
+Compared to a half wave dipole, a full wave loop has a bit of broadside gain due to the separation between the two wires, though that is lessened slightly due to the shortening effect of bending the ends so they join.
+The current on a full wave loop antenna is maximum at the feedpoint, and at the point of the loop opposite the feedpoint. Current is minimum at the points midway between those two. Due to the phase reversal along the wire, the currents are in phase when viewed broadside to the loop.
+If we look at the radiation patterns of regular polygons in free space, fed either at a corner or in the center of one side, there is not a lot of practical difference among them:
+{{:hf:loop_table.jpg?400|}}
 ===== The Mag Loop =====