Chapter 31 Long Line Antenna

After 12 o'clock tonight, a chapter will be updated. Xiaoqiang rushed to the list. If you go to bed late, please help me vote. Thank you!

======

Due to geography, every place in the world has its own local time. As long as the scope of activities is limited to the same time zone, there is no need to care about it at ordinary times. However, radio activity is worldwide. Assuming that the connection between each other uses their own local time will cause great confusion, which has been confirmed by the early rise of radio.

Later, in order to solve this problem, the International Radio Advisory Committee stipulated and recommended a unified time standard - Coordinated Universal Time, referred to as UTC, often referred to as International Unified Time.

It divides the world into 24 time zones. The east and west longitude of the earth is divided into 180 degrees (a total of 360 degrees) by 24 time zones, each of which accounts for 15 degrees. For example, San Francisco in the United States is located in the West Eighth District, 8 hours later than the zero time zone, while Beijing is located in the East Eighth District, 8 hours ahead of the zero time zone.

According to the regulations of the International Telecommunication Union (ITU), UTC should be used and represented by 4 digits in international radio communications unless otherwise specified. The communication between amateur radio stations is carried out worldwide, so UTC should also be used.

Therefore, the opening time of the CQWW_DX competition CW refers to the last weekend of November every year in the sense of UTC. Considering the identity of amateur radio enthusiasts, the organizers of the competition specially arranged the time from 0:00 a.m. on Saturday to 24:00 on Sunday, a total of 24 hours. To get the certificate, it will take at least 12 hours to compete.

Today is Friday, and there is only one week left before the CQWW_DX competition starts.

After school, on the way home, Lin Hong said to Sun Wu, "After practicing, don't rush out and do something for me."

"What did you say?" Sun Wu, who was listening to the song, took off the headphones in his ears.

Lin Hong had to repeat it again.

"No problem!" After Sun Wu nodded, he stuffed the headphones back again.

After a while, Sun Wu remembered another thing, pulled out the headphones again, and said:

"Yes, my cousin said that someone sent a color TV to the other side of the shop. He has never repaired it, and he is a little uncertain. Let me ask you if you can do it."

"I'll go back and have a look. I happen to have something to do these two days."

Color TV is a relatively rare product for rural areas. In the past, in order to make the black-and-white TV look a little colorful, many people pasted a color plastic film in front of the black-and-white TV.

Sun Wu's cousin, Sun Kai, is a relatively flexible person. Before opening a maintenance shop, he knew little about electronic maintenance, but later through self-study, he quickly mastered quite professional knowledge. In the past, if there was a problem, I might have to ask Lin Hong to come out, but now this situation is less and less. I often greet Sun Wu when I encounter some unusual products.

Recently, his income has been greatly reduced, and Sun Wu has been thinking about doing something else to make money.

Back to the waste acquisition station, the two first stood in three-style, and then began to play tricks, and Sun Wu also asked his grandfather to teach them a set of two-person practice methods, and they fought back and there, which added a lot of fun.

Lin Hong remembers the "four wears" and "four tips" practice methods handed over by his master. Every movement is not only in place, but also meticulous in his eyes and expression. He shouts when it's time to shout, stare when it's time to stare, and concentrates every time.

Sun Wu did not agree with this at the beginning and made fun of him from time to time, but Lin Hong ignored it at all. Later, he was severely scolded by his grandfather because of this matter, which restrained him. Over time, he also realized some of the mysteries, and in the process of fighting with others several times, he applied several of them, and found that the effect was very good. From then on, he learned from Lin Hong's appearance and began to practice decently

Unlike ordinary exercise, they practice Xingyiquan more and more energetic. Although they sweat a little, they are out of breathless. Most of the essence of the whole body is closed in the body and rarely leaked out.

"What do you want me to help you with today?" After practicing, Sun Wu was not in a hurry to leave. He was still thinking about what Lin Hong said to him today. After all, it was rare for Lin Hong to take the initiative to ask him with his help.

"I'm going to make an antenna." With that, Lin Hong walked to the room.

Sun Wu followed him and came to the front of the workbench. Between them, Lin Hong drew a drawing from the innermost place.

Sun Wu stretched out his head and saw that there were a few sketches with pencils on it. There were several circuit schematics, and a section that seemed to be something, but he couldn't understand it at all.

"I don't understand this thing. Just tell me how to do it." Sun Wu said very single.

Lin Hong didn't expect him to understand it. He simply explained, "I want to make a long-line antenna..."

Before he finished speaking, Sun Wu interrupted and asked, "What is a long-line antenna?"

Lin Hong thought for a while and couldn't explain it. Finally, he said, "Shuly put, it's an antenna connected to a long wire."

Sun Wu nodded: "Oh... go on."

"Let's first connect the bamboo poles in the room, tie the wire to the bamboo pole, and then you climb to the tree on the other side of the window and help me fix the pole. I need to do some debugging..." Lin Hong pointed to several bamboo poles in the room and gave a general idea of what to do.

The long-line antenna is very simple, as the name suggests, to be long. Generally speaking, its length is preferably greater than one wavelength or even multiple wavelengths. The CQWW_DX competition is divided into six bands, with wavelengths of 160 meters, 80 meters, 40 meters, 20 meters, 15 meters, and 10 meters respectively. For the best results, the length of the antenna should be greater than or equal to 160 meters.

However, for Lin Hong, he can only imagine that he didn't have such a long wire at all. After preparing for a long time, he got a metal wire of more than ten meters, but he could make do with it, but the delivery efficiency was relatively low. Fortunately, the communication mode he planned to participate in was CW, and its impact had been reduced. To the lowest.

The long-line antenna can be placed parallel to the ground or vertically.

If it is placed in parallel, it has a strong direction, just like the Yagi antenna, so if you want to get a better effect, you must constantly adjust the direction. However, because the conditions did not allow, Lin Hong did not adopt this plan, but decided to adopt an upright approach, so that he could rely directly on the trunk of the old locust tree outside the window without occupying space.

adopts the method of upright erection, and a relatively good ground net must be added under the sky adjustment to improve radiation efficiency. Lin Hong prepared 9 meters long plastic copper wire and cut it into 3 sections, each section of 3 meters.