What materials are needed to make a pot lid? How many processes are there?

The diameter of the enamel pot lid is 296mm. There is only one reinforcing ring on the pot lid. Its curved surface is very smooth. The depth of the pot lid is 26mm, which is relatively flat. Use this pot lid to receive a pot of 138 and 146 When there are multiple satellites, the efficiency is very high, but unfortunately it is not easy to buy on the market now; the antenna is homemade, with a diameter of 30 mm. The curved surface of the antenna refers to the 350mm offset antenna of Taiwan Zhongwei. Taking its horizontal curved surface, choose 1- The 2mm aluminum plate is made by beating it with a homemade mold. Its reception efficiency is better than that of the pot lid. The disadvantage is that it requires making a mold and beating it by hand, which is time-consuming and laborious. The diameter of the aluminum pot lid is 320mm, which is made of 1-2mm aluminum plate. It is made by ourselves. It is made by beating on the mold, and its diameter is 320mm. The efficiency is of course better. This is related to the increase in the effective receiving area of ??the antenna. The disadvantage is that the aluminum plate cover or enamel cover with a diameter of 320mm is cut into a miniature pot cover with a diameter of 230mm. Intended to challenge the limit of the smallest diameter of the antenna, the enamel pot lid with a diameter of 380mm, the enamel pot lid with a diameter of 324mm, this kind of pot lid is easy to buy, and the efficiency is the highest, and the efficiency is also good, the aluminum pot lid with a diameter of 600mm, the diameter It is larger, but its efficiency can only reach the level of the Zhongwei 0.45m antenna, and the material is thin and easy to deform, so it is not suitable for use.

Choice of pot lid: The small pot lid is mainly used to receive high-power Ku-band programs. Since it is used as an offset antenna, its focal length is not at the center of the pot, so the curved surface of the pot surface is required to be relatively flat. , if the curved surface is too deep, its efficiency must be very low. For example, the depth of the pot surface of a 0.6m offset antenna is only about 6.5cm. The imported 0.6m antenna has a flatter curved surface, and the depth of the pot surface is about 5.5-6cm. Usually pot lids have 3-6 rings to enhance the strength of the pot lid. The flatter the curved surface of the rings, the better. Rings with obvious steps should not be used because this will prevent all signals from being reflected to high frequencies. on the feed plate of the head.

Another thing to note is that the pot surface should be smooth and clean, and the materials should be thick. As for the size of the pot surface, it is recommended to be between 28-35cm. The efficiency will definitely be better if the pot surface is larger, but if it is too large, it loses the meaning of homemade, and if the curved surface is wrong, the efficiency will be counterproductive. In the test, the efficiency of an aluminum pot lid with a diameter of 45cm is not as good as that of an enamel pot lid with a diameter of 35cm. This is because the surface approximation is not high. This article recommends three types of pot lids and homemade antennas. The former saves trouble and can be bought It is useful, the latter is time-consuming and labor-intensive, but the efficiency of the antenna is good.

About the focal length of the LNB and the antenna:

Usually, the calculation formula used for the feedforward antenna is the square of the antenna radius divided by 4 times the depth from the center point of the antenna to the pot surface , take a commonly used 1.5m antenna as an example, its radius is 75cm, the depth of the pot surface is 25cm, find the focal length A, radius Y=75, antenna depth H is 25, substitute the formula A=752÷(4×25)= 56.25 (cm). Since the designs of antennas from different manufacturers are not necessarily the same and the production processes are not exactly the same, the focal length is only an approximate value. There is a quick way to find the focal length, which is to remove the pot surface from the adjusted offset antenna, hold the pot lid, place it on the original antenna surface, move it up and down, back and forth, find the best focal length and elevation angle, and measure and record Come down. Based on these data, a bracket can be made, and the pot lid can be fixed on the bracket. This method avoids the pain of blind search and saves a lot of time.

Installation method: Use a pot lid as an antenna. It is better to install it upside down. Because of its high elevation angle, it borrows the sky but not the ground, takes up little space and is easy to fix, thus improving the stability of the antenna. Material selection and production of the bracket When making the bracket, you can consider the different placement positions and convenience of material selection. Here are several manufacturing methods and related dimensional data. ctvro.cn

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1. Use shelf angle steel to make the antenna bracket ctvro.cn

The characteristic of using this material is that it is easy to purchase. This angle steel has all strip holes and only needs to be connected with screws, making debugging very convenient and processing easy. After the size is determined, the store can cut it for you. The focal length and position of the LNB and the pot cover are provided. The size is for reference only, because when different pot lids are used, the focal length is different, the installation size and elevation angle are also different, and the diameter of the pot surface is also different. 35cm, choose 30×30mm angle steel, each angle steel is connected with 6mm screws, the low plate is made into a T shape, and three three-point feet are made under the angle steel, the height of the feet is 10-15mm, so that it can be placed on the ground or The tables and cabinets are very stable. It is used between the front end of an angle steel and the front angle steel for fixing the pot lid and adjusting the elevation angle. The hinge is fixed, and the rear end is fixed to an angle steel at the back with M6 screws. It is very simple to make the upper and lower seat brackets. It is best to cut them to size and then assemble them. This triangular base structure is strong enough, easy to move, and can be used both inside and outside the balcony. This antenna can be placed and used. ctvro.cn

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2. Use the bracket made of PVC pipe ctvro.cn

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Use this The material used to make the bracket is characterized by easy access to materials and simple processing.

Made into a floor-standing type, it is very convenient to move and debug, and is suitable for placement on the balcony. All PVC pipes are connected through PVC tees or elbows with PVC special glue. They can also be installed at three points in the T shape. Three 10-15mm feet make it more stable when placed on the ground. For joints that need to be adjusted, such as elevation and focal length, M6 expansion screws can be cleverly fixed in the elbows of the joints. The specific method is: Remove the expansion tube from the expansion screw and make a 3.2mm through hole at the end of the screw. Open a 3.2mm counter-hole on the PVC elbow and fix it with the long M3 screw. The only drawback of this antenna is that it occupies the indoor space. Or the balcony has a larger space. ctvro.cn

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3. Table lamp stand ctvro.cn

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Refer to the table lamp and microscope For the appearance, choose an indoor antenna bracket for an open-circuit TV, remove the original rod antenna, etc., and use its base and elevation adjustment parts. There are several options for the finished product of this kind of bracket. You only need to consider whether its elevation adjustment is light and flexible, and its appearance is beautiful. This type of bracket is made of plastic shell and is very light in weight. It is easy to tip over and become unstable after being used as a satellite antenna. An iron plate must be added to the bottom of the shell to increase its own weight. Most of the screws for adjusting the elevation angle on this kind of bracket are made of plastic, which can slip easily and must be replaced with metal screws. In order to facilitate the adjustment of the elevation positioning, a piece of rubber skin, such as a tire, can be placed on each side of the screw to increase its friction. When the elevation screw is 80% tight, the pot surface will not slide down when the elevation angle is changed by hand. This style of The stand is very small and flexible, and is well made like a handicraft. It is suitable for placing on a table cabinet or on the sill of an indoor bay window. ctvro.cn

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This kind of bracket is very simple to make, and it is rare to make it yourself. ctvro.cn

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(1) Antenna fixed bracket ctvro.cn

Select a steel bar with a width of 20mm, a length of 500mm, and a thickness of 1-2mm , bent at 180mm, with some curvature on both sides, used to fix the antenna and high-frequency head respectively. The bracket is made of local materials and connected by two steel bars. ctvro.cn

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(2) Strengthen the edge strips. After the antenna is debugged, measure the distance between the pot surface and the high-frequency head fixture, and use a 10mm metal strip , with a thickness of 0.8-1mm, one end is fixed on the high-frequency head fixture, and the other end is fixed on the pot surface, mainly to prevent the high-frequency head from shaking. The reinforced edge strip is made of plexiglass, and a soldering iron is used at the bend Made by heating. ctvro.cn

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Homemade desk lamp antenna bracket c

tvro.cn4. Make bracket with steel plate

The characteristic of using this method of production is that it is particularly convenient to adjust the focal length and elevation angle, because the method of opening strip holes and multi-point round holes in each adjustment part is adopted. The structure is simple and strong, and the materials are easy to obtain, but the structural parts need to be homemade. , which is more time-consuming and can be used both inside and outside the balcony.

(1) The main steel plate for fixing the antenna is 1-2mm thick, 100mm wide, and 450mm long. Bend it 45o at the 50mm connection with the elevation-adjusting steel plate. Tap 2 M4 holes on the main steel plate. Bend 16mm at the front end 45o, tap 2 M4 screw holes, and connect it to the bracket fixed on the base. The bracket is 40mm wide, 80mm long, and bent 90o at 15mm.

(2) The elevation adjustment steel plate is 1.5mm thick, 100mm wide, and 180mm long. There is a strip hole 28mm away from both sides. The hole is 4.2mm wide and 95mm long. This hole is used to adjust the antenna elevation angle. .

(3) The connection between the elevation adjustment steel plate and the base is made of 25×25mm angle steel, 200mm long. You can also bend the steel plate 90o or extend the column steel plate by 20mm and then bend it 90o. This component can be omitted.

(4) The upright column is made of 1-1.5mm thick, 25×25mm angle steel, 220mm long, or it can be made by bending the steel plate 90o, and tilting one end 10o at the connection with the main steel plate of the fixed antenna and then bending 90o, bend the other side 90o, open one or two M4.2 holes in each bend, and connect it to the main steel plate. The reason for the tilt of 10o is because the focus of the high-frequency head is not in the center of the pot antenna, and it is biased. If it is more, it is less. It depends on different

"pot" debugging.

(5) Fixed high-frequency head adjustment bracket. Use a 1-1.5mm thick steel plate, 40mm wide and 210mm long. Bend 90o at 10m on both sides. A row of M4.2 round holes should be opened in the middle of the bracket. Or a strip hole to adjust the focus of the tuner.

(6) For the high-frequency head bracket, use a 1mm steel plate to make a clamp at the fixed position of the high-frequency head. This clamp is connected to the adjustment bracket and can also be used to adjust the focal length of the high-frequency head.

When using this antenna to receive 138oE and 146oE from multiple satellites in one pot, the fixture of the high-frequency head cannot be a finished plastic fixture, because the two high-frequency heads are closely together and can only be made of aluminum alloy. Bars or steel bars are homemade.

The antenna was placed on a flower stand outside the balcony, and the bottom was fixed with a scrapped computer case. Such a small antenna has very little wind resistance and is very stable.

5. Production of wall-mounted brackets

When small antennas are installed on the wall, they are generally installed outdoors. This installation method is very popular because it does not occupy the indoor space. Space. This self-made bracket can be installed on the floor or on the wall.

The main job is to make a set of universal structural parts that can be easily adjusted up, down, left, and right. The universal structural parts of this bracket are made of plastic rods or bakelite rods. After the elevation and azimuth angles are adjusted, M6 can be used Tighten the screws, and use M4 screws to connect the antenna and the gimbal structure. Use a steel bar 20mm wide, 400mm long, and 1-2mm thick to bend at 160mm. There are some curvatures on both sides to fix the antenna and high frequency respectively. head.

The pipe can be a tap water pipe or a stainless steel pipe. Its inner diameter can match the outer diameter of the universal rotating part. Fix it with screws at both ends of the pipe. Weld a 100×100mm square plate to the bottom of the pipe. Open M7 holes in the four corners to fix the antenna. The length of the tube is related to the size of the antenna. If the antenna is 300mm, the tube length is 160mm.

Homemade antenna

1. Production of 300mm "forward feed" antenna

(1) First make an iron box with a steel plate, with a thickness of 4mm and a width of 50mm , 1010mm long, roll it into a positive circle with a bending machine, and weld the two ends.

(2) Make an antenna curved panel template. The curvature of this template refers to the 350mm offset antenna of Taiwan Zhongwei. Take its horizontal curved surface and make it with a plastic sheet cutter and file. Tried and repaired until it matched the lateral curved surface of the Taiwan Zhongwei 350mm offset antenna.

(3) Cut a 320×320mm aluminum plate. The thickness of the aluminum plate is 1-2mm. You can also use a 0.5mm-0.7mm thick steel plate. Place it on the iron hoop and beat it with a wooden hammer to roughen it. Processing, after it is basically formed, use the calibration template for detailed processing. At this time, you should use a rubber hammer to hit it, test while knocking, and finally make the curved surface of the antenna fit the calibration template. It takes some experience to hit the curved surface of the antenna manually, and it is best to It is done by an iron metal worker or a tinsmith, which is fast, accurate and beautiful.

(4) On the center of the processed antenna, use a compass to draw a circle with a radius of 150mm, use large scissors to cut off the excess edges along the outer circle, use a file to remove burrs and correct them. You can also spray your favorite color or pattern on the antenna surface, so that the antenna is basically finished. (Thanks to Teacher Song Youquan for providing the above information)

The actual use effect of a small pot lid antenna

The cost of making a homemade pot lid antenna is not high, and pot noodles can be bought in daily miscellaneous department stores , an ordinary enamel cooking pot cover costs 3-4 yuan, and the steel plate material for the bracket can be purchased at a scrap store for about 3-10 yuan. However, the most important thing for a homemade antenna is to achieve miniaturization and practicality, not price and cost. Generally speaking, this type of small antenna is suitable for use on high-power live broadcast satellites. After testing with many pot lids, we selected several practical pot lids as the antenna. The first choice is the pot lid, which has a diameter of 296mm. The effective receiving diameter is 280mm, and the edge of the pot is 8mm, which is flat and the signal cannot be reflected to the feed source. The curved surface of this kind of pot cover is relatively flat, the depth of the pot surface is 26mm, and there is only a reinforcing ring transition in the middle. If you can't buy a pot lid with this shape, you can buy another pot lid with a diameter of 324mm and an "effective diameter" of 294mm. If there are multiple stars in one pot, the efficiency is close to the former, but it is easy to buy. Over 296mm pot cover when received.

One thing that needs to be explained here is: the parameters in the following tables are all measured and are for reference only, but can be used for comparison. It should be noted that the recorded parameters are closely related to the weather, receiver threshold, tuner, local signal field strength, antenna installation environment and debugging accuracy.

The antenna has 138 as the main focus and 146 as the secondary focus. It can be viewed normally in rainy weather and the picture is smooth. When it rains, you can still watch normally if there are no raindrops accumulated on the pot surface. At this time, you can place this antenna on an unobstructed balcony for use. On sunny days, when it is on the balcony and received through a window with a thickness of 5mm, the signal quality will be better. dropped by 8%, the picture can still be viewed smoothly; when passing through two layers of 5mm thick windows, the signal quality dropped by 14%, and some transponders appeared mosaic, but transponders with strong signals could still be viewed normally. The specific signal quality of the antenna when receiving double stars on a clear day. The receiver is CP-7885.

When the signal quality is full, it is 100%. After a few months, the usage has been normal, achieving the purpose of practicality and miniaturization.

The antenna, with a diameter of only 230mm, was cut with scissors from a pot surface with an original diameter of 290mm. The depth of the pot surface is 18mm. The purpose is to test the limit of the minimum diameter of the antenna. When a single star receives the two satellites 138oE or 146oE, there is still some room for signal quality and the picture is smooth; when placed in an unenclosed balcony or on an indoor window sill, when a single star receives the two satellites 138oE or 146oE, you can watch and watch normally on sunny days. There's still some headroom, the picture is smooth, and its specific signal quality. The receiver is CP-7885, the tuner is Baichang 525, and the local oscillator is 11.3GHz.

In the signal quality measured by the antenna, "window opening" is the data measured when the window is opened on the balcony. "Closed" is measured when passing through 1 layer of 5mm thick glass window. When encountering light rain, you can still watch normally with the window open, which basically achieves the goal of achieving the minimum limit of the antenna diameter.

Single satellite reception data when the pot lid antenna is used.

Some rules can be summarized from the depth of various pot lids: Under normal circumstances, the depth of the pot surface is about 9% of the diameter. You should try to choose a pot surface with a shallow depth and a flat transition surface, and the basic efficiency is relatively high. In addition to receiving 138oE or 146oE, this antenna can also receive programs on the 113oE Palapa-C2 satellite. The signal quality of the 11472Mhz group of transponders is 55%, and the 1132Mhz group is 35% of the single satellite data. , the data of these two sets of transponders were tested before the real-world operator of the 113oE Palapa-C2 satellite stopped broadcasting, and the picture could be watched smoothly. We also tried to receive Sino-1, and the signal quality was 12780V 41530- 44%, the three groups of 12440 V 41530, 12500 V 41530, and 12560 V 41530 are all 36%, 12620 V 32553——44%, this data is also using the receiver CP-7885, Baichang 525 high frequency head (11.3GHz) Actual measurement.

This kind of small antenna has good prospects and practical value in its application in high-power live broadcast satellites in the future.

The actual measured data of the antenna, this data was measured on the balcony, the receiver is Hangke 430, and the tuner is Baichang 525 (11.3GHz).

The actual measured data of antenna viewing, this data is measured outside the balcony, the receiver is CP-7885, the tuner is Baichang 525, 11.3GHz.

Test reception of 76.5-degree Asia-Pacific 2R

The antenna can only receive one group of 12375Mhz Tibet stations, the signal quality is 55%, and the others are all 0, so I can only give up and the author chooses A 380mm aluminum pot lid was tested. Most transponders can receive it, but the margin is not large. The signal-to-noise ratios of two groups of transponders are 24, 25, 26, and 27. The measured data were actually measured on the balcony. The reception The aircraft is Hangke 430, LNB Bubaichang 525, local oscillator 11.3G. This data was recorded and photographed in 2004. The purpose of this test is just to see its effect, and it cannot be used for normal reception.

Some feelings after the experiment

This experiment of using pot lids and aluminum plates and galvanized plates to make antennas left a deep impression on us, and we also felt the success. Joy, it proves that there is still a lot of potential to be tapped in terms of antenna efficiency, such as the size of the curvature of the surface, the difference in materials, the length of the focal length, etc. The author has seen 0.45-0.75m offset antennas and flat panel antennas from brands such as Sony, Toshiba, Diba, Panasonic, Aiwa, and Gosbell. They are very beautifully made. We have also used some imported brands of offset antennas, and they are very particular in terms of workmanship and packaging and are impeccable. Its efficiency is indeed higher than that of domestic antennas of the same caliber, and its focal length is relatively short. The accessories it comes with are also very thoughtful, such as tuners, cables, F-heads, tools, etc.; the clamps are also multi-purpose and suitable for It is fixed in many environments and users can install it according to the picture after buying it. The author has used a 0.45m imported second-hand antenna to receive programs on 76.5oE Asia-Pacific 2R. All 11 transponders received it normally. Although some transponders have little signal quality margin, the picture is still very smooth. Made in China The 0.45m antenna cannot be fully connected.

There are no less than 100 factories producing antennas in our country, and the number is still increasing. However, only 3% of the factories have the ability to test antenna performance and technical indicators. At the same time, the production technical standards of each factory are the same and copied here and there. At present, the minimum diameter of the domestically produced offset-feed antenna is 450mm and the focal length is 270mm. The pot diameter is only 296mm and the focal length is only 188mm. The pot diameter is only 230mm and the focal length is only 179mm. It is really very small. The minimum diameter of domestically produced feedforward antennas is 1000mm, which cannot meet the needs of users, and factories produce very few high-quality products. Most factories are unwilling to invest funds in scientific research and development. Many antenna molds are copied and imitated, and corners are cut on materials and processes. The production is rough, the efficiency is very low, and the lifespan is extremely short. This may be the result of the vicious cycle of price competition. In previous quality evaluations, there are many unqualified ones. I hope this article can provide some inspiration to antenna manufacturers: if manufacturers can invest more in development and design, check the materials used, work hard on antenna caliber and efficiency, and improve production processes, then high-gain high-quality antennas can also be produced. It will definitely appear in domestic and foreign markets, and efficient small antennas will not be a dream.