JYR4010 plus End-fed Shortwave HF Antenna 4 Band 7/14/21/28MHz Joint Waterproof

Antenna introduction How can it be called a long wire antenna? Do you just pull a thread? Do not! Strictly speaking, that's just. The name of the antenna should depend on the operating frequency. If the length of the antenna is exactly half the wavelength, it is called a Ziber antenna, also called a terminal-fed dipole antenna. An antenna whose length is greater than one wavelength is called a long-line antenna. A more strict definition can be summarized as: an antenna whose length is greater than one wavelength and an integer multiple of a half-wavelength can be called a long-line antenna. So when we use the same antenna to work in different frequency bands, the name of the antenna is different? For convenience, we call the antenna that works in the low frequency band as a long-line antenna. Why use a long wire antenna (1) It is not easy to set up an antenna in a city. This antenna is very simple to set up. (2) It has a slight gain, and has a better effect than a dipole antenna in its larger radiation direction. (3) The short-range directionality is not obvious. (4) The need for mobile emergency communications, quickly erected. Note: The advantages of long-line antennas are simple structure, low price and moderate gain. Compared with the Yagi antenna and the anti-polar periodic antenna, the long-line antenna has lower length directivity and gain. But its advantage is that because its gain is related to the line length, the user can find the length and angle suitable for the receiving line. By comparing the signal wavelength, the length of the line is calculated, which is very suitable for long-distance communication. When the line length is 4 times the wavelength and the elevation angle is 25 degrees, the gain is 3dB higher than that of the dipole antenna. When the line length is 8 times the wavelength, the gain is 6dB higher and the elevation angle drops to 18 degrees. Antenna model: JYR4010plus (4-band 7/14/21/28Mhz) Antenna configuration: 1, 1 end-fed balun, 1 storage bag 2. 2.5 square vibrator 20 meters 3. 20m outdoor drawstring. If you don't include the feeder, you need to buy it separately. The store has a feeder for sale. Welcome to buy. 4. Input power: transmit in 30 seconds, receive in 30 seconds, below 150W in ssb, cw mode, below 100W in FT8 mode, below 70W in AM.FM, SFK mode, the following figure 67.9 degrees is measured for long-term use, when the transmission is longer than the receiving time When proportional, the transmit power must be appropriately reduced. Antenna erection: The end-fed antenna has low requirements for erection, and it can work normally if it is more than 2 meters away from the ground, but in order to achieve the desired effect, it should be as high as possible and as open as possible. When the antenna is erected vertically, the communication is far away due to the low elevation angle. , When erected horizontally, due to the high elevation angle and the close communication, it also has a certain directionality. Shipping volume: 25x15x13cm, shipping weight 1.2KG