Whip Shark Antenna is the most commonly used antenna for walkie-talkies. This straight rod-shaped metal structure has become the symbolic configuration of communication equipment long before the advent of mobile phones. Its working principle is to convert electrical signals into radio waves and receive external signals efficiently, which has the characteristics of simple structure and high signal radiation efficiency. Today, despite the miniaturization of electronic equipment, walkie-talkies still retain external antennas, which is essentially determined by the physical laws of electromagnetic wave propagation. The working frequency of the walkie-talkie is concentrated at 409-410MHz. According to the formula "wavelength = speed of light/frequency", this frequency band corresponds to a wavelength of about 73-74cm. The core theory of antenna design shows that the ideal length should be 1/2 of the wavelength (i.e. 36-37 cm) to realize high-energy signal emission. If the antenna size is forcibly shortened, the "impedance matching" between the antenna and electromagnetic wave will be unbalanced, and the signal strength will be exponentially attenuated. The measured data show that when the antenna length is reduced to 1/3 of the ideal value, the communication distance will drop from the conventional 3 km to less than 500 m, and the ability to penetrate obstacles such as walls and vegetation will drop by over 60%. Therefore, the external ISDB Antenna is a necessary design to ensure long-distance and anti-interference communication. The 900MHz/1800MHz band used by mobile phones has shorter wavelengths (33 cm and 16 cm respectively), and the high-frequency characteristics make it possible to receive signals through a built-in Patch Antenna (such as PIFA), and it is necessary to take into account multiple functions such as battery life, screen and camera. The walkie-talkie has a single function, and the communication effect is the core competitiveness-in complex scenes such as construction sites, mountainous areas, underground garages, etc., we must rely on the physical length of external antennas to maintain signal strength. This design logic of "sacrificing portability for communication efficiency" is the fundamental difference between professional communication equipment and consumer electronic products. The walkie-talkie retains the external antenna, which is the result of the dual functions of "band characteristics+function priority": the long wavelength of 409MHz band requires the antenna to have sufficient size, and the rigor of communication scenarios does not allow for compromise for portability. From military walkie-talkies in the 1940s to modern civilian models, whip antenna has always been the best footnote for "clear hearing and far Transmission", which also confirms the eternal principle of "performance takes precedence over form" in professional equipment design. 1. Why does the walkie-talkie rely on the exposed whip antenna? Whip Antenna is the most commonly used walkie-talkie. Its design essence is determined by the physical characteristics of 409-410MHz band: this band corresponds to the wavelength of 73-74 cm, and according to antenna theory, the ideal transmission length needs to be 1/2 of the wavelength (about 36-37 cm). If it is shortened to 12 cm (1/3 of the ideal value), the signal strength will decline exponentially due to "impedance matching imbalance", the communication distance will drop from 3 km to less than 500 m, and the ability to penetrate obstacles will drop by more than 60%. 2. Why can mobile phones have built-in antennas but walkie-talkies can't? The core difference lies in the band frequency and function positioning: the 900MHz/1800MHz band used by mobile phones has a shorter wavelength (33 cm/16 cm), which can be integrated through micro-patch antennas (such as PIFA); And the mobile phone needs to take into account multiple functions such as battery life and screen, and the signal is the basic requirement rather than the only standard. However, the walkie-talkie has a single function. In construction sites, mountainous areas and other scenes, it is necessary to rely on the physical length of external antennas to maintain long-distance communication, and sacrificing portability is a necessary compromise to ensure signals. 3. Can the design logic of whip antenna be subverted? It cannot be subverted in the short term. Although modern technology optimizes portability through spiral loading and foldable design, the long-wavelength physical law of 409MHz band cannot be broken-if the built-in antenna in high frequency band is used, the signal penetration ability will be weakened by more than 40%, which cannot meet the needs of professional scenes. From military aircraft to modern equipment in the 1940s, whip antenna always follows the principle of "performance takes precedence over form", which is the optimal solution of the game between "long-distance communication is just needed" and "electromagnetic wave law".
