Chapter 666: Radio broadcast

Qi’s weapon imitation has just begun, but Qin has already begun another revolutionary technological achievement that has epoch-making. This is radio technology.

With the continued research on tube technology, radio technology has developed rapidly, but Zhong Shangwen has made full use of spare time to help its technology become more mature in order to speed up its promotion.

The previous Qin State radio technology only sent out some meaningless radio signals, which had no information value. Later, the radio technology improved the electron tube technology and used the vacuum electron tube as the signal receiving device. In this way, the foundation of radio technology has laid a solid foundation. But this is far from large-scale popularization. Because these devices are still large. This requires further simplification of these technical equipment.

Shang Wen first checked the materials currently used by Qin Guo. Among these materials, he did not see the materials he most wanted to see. Silicon, which is a good semiconductor material. But he rummaged through all the records and explained that there was no indication of the existence of silicon.

Silicon does exist around us, and it is the second most abundant element on the earth, but it mostly exists in the form of oxides in nature. However, Qin State was able to invent the vacuum tube because another element was discovered before going further. Developed, this element is germanium, which is also a good semiconductor material.

Germanium is a rare element, and there is no ore for industrial mining. It occupies 7.0×10-4 by mass in the earth's crust, and contains a small amount in coal, silver, tin, zinc, copper and other minerals. Industrial production is mainly recovered from zinc sulfide ore, coal and metallurgical waste or flue dust. The discovery process is the same as industrial production, and it is also discovered from it.

The scarcity of this element determines that it cannot be mass-produced on a large scale. Shangwen decided to extract pure silicon first. In the laboratory, magnesium powder can be used to reduce the powdered silicon dioxide under red heat, and the generated magnesium oxide and Magnesium powder is washed with hydrofluoric acid to remove the unacted silicon dioxide to obtain elemental silicon. The amorphous silicon produced by this method is not pure enough, which is brown-black powder. The industrial production of silicon is the reduction of silica (SiO2 content greater than 99%) in an electric arc furnace. The reducing agent used is petroleum coke and charcoal. When using a DC electric arc furnace, all petroleum coke can be used instead of charcoal. Petroleum coke has low ash content (0.3% to 0.8%), and high-quality silica (SiO2 greater than 99%) can be used to directly produce high-quality silicon for silicon steel sheets. High-purity semiconductor silicon can be obtained by reducing high-purity trichlorosilane SiHCl3 or SiCl4 with hydrogen on a hot silicon rod at 1,200°C. Ultra-pure single crystal silicon can be prepared by the Czochralski method or zone melting method. Shang Wen wrote in detail the method of preparing silicon in the modern electronics industry.

After extracting pure silicon. It is to manufacture circuit boards and diodes or triodes. Shang Wen believes that it is best to make a triode, because the triode can amplify weak signals.

After seven consecutive days of continuous research, Shangwen has initially completed the development of the diode, but the triode still needs further upgrades of some materials to complete, but the vacuum tube can already complete the reception of electric wave signals.

Some high-rise buildings in Qin State have built some steel towers, not only lightning rods, but also signal receivers. This is the result of continuous testing of radio signals.

Broadcasting stations broadcast programs by first converting the sound into an audio electric signal through a microphone, and then being amplified by a high-frequency signal (carrier). At this time, a certain parameter of the high-wave signal changes accordingly with the audio signal, so that we want to transmit it. The audio signal is contained in the high-frequency carrier signal. The high-frequency signal is amplified again, and then when the high-frequency current flows through the antenna, it forms a radio wave that is emitted outwards. The propagation speed of the radio wave is 3×10 8 square meters per second. This radio wave is received by the radio antenna, then amplified and demodulated, restored to an audio electric signal, sent to the speaker voice coil, causing the corresponding vibration of the paper cone, and then the sound can be restored, that is, the sound-electric conversion transmission—— The process of electro-acoustic conversion.

The broadcasting principles of radio stations are already known, so the next step is to popularize this kind of receiving device on a large scale. Now Qin needs a simpler receiving device to popularize this kind of radio.

However, Qin soon had a cheap radio, this is the mineral radio. Mineral radio refers to a passive radio without amplifying circuit composed of antenna, ground wire, basic tuning circuit and ore as a detector. It is the simplest radio receiving device. The mineral radio was first used by Qin Guo as a detector. But he now has the biggest use, that is, receiving radio broadcasts.

However, this mineral radio has a big disadvantage. That is, it can only be listened to by one person, and the reception performance is relatively poor.

Shangwen’s products are DC radios and AC radios. The tube radio uses two sets of DC power supplies, one set for filament power supply and one set for anode power supply, and consumes a lot of electricity. It will not take a long time to replace the battery. Therefore, the use cost of the radio is relatively high. The radio is cheaper than the direct current tube radio. , But due to the large size of the electronic tube, high power consumption, severe heat generation, short life, low power utilization efficiency, fragile structure and the need for high-voltage power supply shortcomings.

Transistor radios require the invention of transistors to be widely popularized. With the current level of technology, it is estimated that there is still a certain degree of difficulty.

Whether it is mineral radio, or DC tube radio and AC tube radio, as well as the future transistor radio. Qin Guo finally started a new information dissemination on the radio. And Qin Guo media began to move from newspaper to wireless. A new kind of media was born in Qin.

"Good afternoon, ladies and gentlemen. Welcome to Wenyang Radio. I am the announcer Xiaobai. Today I am excited and very happy, because our country has new news tools. This is a huge change from literal to sound. "Although this is not the first voice of Qin State on radio, it is the first radio broadcast voice of Qin State.

Mineral radios are widely popularized in ordinary people's homes. This kind of cash register that only requires three and a half is cheap and durable, but it is not clear. Rich people buy AC radios to listen to programs. Whether it is the rich or the middle class. For the first time, Qin State transmitted sound in radio waves.

However, the radio can only cover one place in Xianyang, and has not yet been able to cover all the places in Qin State. Because this involves a high-power radio. The emergence of radio broadcasting quickly attracted the attention of the military, who believed that this kind of transceiver device without wires was much lighter.