Precautions for twisted pair transmitter

The advantages of twisted-pair video transmission have indeed strengthened our confidence in using twisted-pair video transmission equipment in engineering. However, in actual product purchase and wiring applications, there will still be some problems, and Utepu employees have carried out A summary is as follows:

1) In order to enhance the anti-interference ability, use shielded wire by yourself. Some friends have unconsciously applied the experience of using coaxial cable as the transmission medium to twisted-pair transmission due to the long-term use of coaxial cable for transmission, thinking that the use of shielded twisted-pair cable has better performance in anti-interference. However, In fact, the use of shielded cables does enhance some anti-jamming capabilities, but it severely damages high-frequency signals, the color of the transmission effect becomes worse, and there is no color image at a long distance, and the transmission quality is greatly reduced. At the same time, the price of shielded twisted pair is high, which increases engineering costs. Therefore, wiring is the first to pay attention to this problem.

2) In order to reduce engineering costs, blindly select low-priced products. Any product has a certain reasonable price. Good mobile phones are beautiful in appearance, easy to use, and durable, but they are expensive. The reason is that a lot of work has been done in industrial design, quality control, materials and technology, etc. Need to invest in costs, the natural price is higher than some other brand mobile phones. At present, most of the twisted-pair transmission equipment manufacturers in my country are small private enterprises. A relatively reasonable price can not only bring benefits to users, but also ensure that the manufacturers have a relatively stable power. They will not be closed in 3 or 5 years. There is a problem with the product on hand and I don’t know who to fix it. Twisted-pair transmission equipment has been a matter of recent years. The market price is in a mess. Some friends first consider the price when buying products, and then consider the quality and after-sales service. This put the cart before the horse. It should be clear that the project we are doing is a security project. Therefore, the entire system of the security project must be of reliable quality. Otherwise, the quality will not pass, and the system itself will have problems. How to monitor the small actions of the kittens and puppies. It is difficult to buy reliable products at ultra-low prices. If you do, you may have to consider the quality of the product or the pros and cons of after-sales service. Of course, there are some companies that have done a good job of cost control, and their price/performance ratio is very competitive, but such companies in China are rare and very few.

3) Blindly believe in the waterproof, anti-interference and lightning protection capabilities of the product. Most companies claim that their products are waterproof, anti-interference and lightning protection during publicity. Therefore, when communicating with customers, in order to convince customers of these capabilities of their products, they should actively bypass the rainy, strong interference and There is no end to the area of direct lightning strikes. After purchasing the product, customers will naturally not attachgreat importance to these places that should be avoided. As a result, interference phenomena and direct lightning damage may occur. Just imagine, tens of thousands of voltsof lightning can split a big tree into several petals. What is a small twisted pair transmission device? ! The case will be melted by it, so what can the detonator do? Therefore, wemust seek truth from facts in wiring, try to avoid them, the farther the better, and at the same time improve the environment of product storage, so that the equipment can work stably in a clean and dry environment.

4) Rough wiring process leads to poor video effects. In fact, the unshielded twisted pairs we buy on the market are all 305 meters in a box, but the points in the project are one on the left and one on the right, which is far and near. Therefore, the network cable needs to be broken for short places less than 305 meters. Pick out the wire for the camera. If it is long, you need to connect the wires of two or more boxes. It is best to solder and wrap the wires when wiring. At the same time, pay attention to the twisting of the twisted pair to ensure that There is no problem with the transmission line.

5) Going to two extremes, causing unnecessary waste. It is unscientific to use long-distance transmission equipment for short distances and use short-distance transmission equipment for longer distances. In order to make the video effect better, some friends often use the 1200-meter transmission equipment at 500 meters at the cost. In fact, this is unnecessary and a waste. There are more economical products for medium and short distances. Some do not require power supply, which is more stable and very economical. In today's energy shortage, we advocate effective conservation. On the contrary, it is unscientific to use equipment that normally works at 300 meters at 500 meters. Can a 10-year-old child carry a load of 100 kilograms? This can only increase the risk of equipment damage, and the displayed effect is also not good.

6) The wire is too poor, resulting in frequent disconnection. When wiring twisted-pair video transmission equipment, most of the two wiring methods are adopted. One is to directly remove the two wires of a pair of wires and connect them to the two terminal posts of the device; the other is to use RJ45 The crystal head comes to pick it up. Both methods have their advantages and disadvantages. The screw-free spring terminal is better in contact and can ensure good contact between the nodes. However, the twisted-pair wire is thin and it is not easy to handle without special tools. The quality of the wire is not good, and the wire that is pulled out may be very brittle and cannot withstand the toss; using the crystal head to connect it makes people feel very *, but the actual effect is not good, because the contact of the crystal head is *elastic, and the time is long. It may cause poor contact. In addition, we usually only use one of the four pairs of twisted

-pair cables at one point. It is obviously a waste to put all four pairs in the crystal head. Therefore, the best way is to still take the form of screw-free spring wiring Ruizi, but when purchasing wires, check the quality and use brand-name wires as much as possible. Some people worry about whether the two thin wires can withstand the pulling force generated by the weight of the longer wire when wiring in the form of binding posts. This worry is normal, but we have a way to deal with it, as long as the whole wire is placed near the terminal This kind of worry can be completely solved by fixing the twisted pair.

7) In-depth research, lack of patience, and failure to adjust the best results. When using the twisted pair transmission equipment for the first time, I saw the thin page of manual and felt that the installation was just a piece of cake, so I read the manual and started to do it. However, the actual adjustment is far from the case, because the adjustment , The transmitter and receiver must be adjusted, and the location of the transmitter is often hundreds of kilometers away, the personnel on both sides need to use the walkie-talkie to continuously coordinate, this kind of work is easy to make people upset, so problems are easy to produce, many For the first time users, it is easy to sprinkle air on the twisted pair transmission equipment. The solution to this problem is that the specific construction personnel must first read the manual thoroughly, and secondly estimate the distance between the two points based on the actual situation, first determine the dial position of the transmitter, and then let the construction personnel on the receiving end make appropriate adjustments. It means that the estimation is wrong, and it needs to be re-estimated. After the dialing code is set at the transmitting end, the personnel at the receiving end will make another adjustment. In this way, the best effect can be easily adjusted. The key is 1, we must emphasize an adjustment sequence, 2, we must hold a research attitude, and do it patiently, comprehensively, and seriously.