Do you have a pan-less satellite TV receiver?

Reveal the secret of satellite TV reception without pan

-Also talk about a new type of satellite receiving antenna

At present, in China, due to the policy restrictions, individuals are generally not allowed to install and use satellite ground receiving facilities. For this reason, some unscrupulous merchants took the opportunity to advertise the product of "no pot reception" of satellite TV, claiming that it is attractive to use this product to receive satellite TV signals without setting up an outdoor receiving satellite TV "pot".

As for the so-called "no-pan reception" of satellite signals, some merchants advertised that "the high-frequency, no-pan reception and anti-interference equipment produced by adopting the internationally advanced AOMM double-layer magnetic high-frequency digital compatibility technology, GPS global positioning system and SOS automatic search system will replace the pan surface receiving system!" Some readers are confused by these technical terms that seem to be incomprehensible, seemingly heard and unheard of, and I wonder if there are such satellite receiving equipment. In our previous magazines, it was not introduced in depth. Here, we will use this article to take you to unveil the "no-pot reception" of satellite TV signals, and also introduce the new satellite receiving antenna technology today.

what is the "pot" in satellite reception?

The "pot" in satellite reception is an image saying. Because the parabolic antenna is often used in satellite TV reception, and the reflecting surface of the parabolic antenna is similar to the iron pot we use in our daily life, people call it the satellite "pot" or "pot cover", which is simply called "pot".

There are two kinds of parabolic antennas: positive feed antenna and offset feed antenna. The reflecting surface area of positive feed antenna is relatively large, so it is commonly called "cauldron". The reflection area of the relative offset feed antenna is relatively small, which is called "small pot" or "small ear".

Some satellite enthusiasts use the antenna made of pig iron, which is common in rural areas, to receive KU-band signals. Hehe, this is the real pot!

the new satellite receiving antenna realizes "pan-less reception"!

according to the definition of satellite "pot" above, we can definitely answer that "receiving without pot" can be realized. Because the satellite "pot" (that is, parabolic antenna) is only a member of the large family of satellite receiving antennas, it is only a receiving equipment made by using the reflection principle of electric waves; In addition, there is a new antenna which uses the principle of direct and refraction of electric waves to receive satellite signals, which is what we call "no-pot reception".

At present, there are three kinds of satellite receiving antennas: horn antenna, flat antenna and lens antenna. Among them, horn antenna and flat antenna use the principle of direct radio waves, while lens antenna uses the principle of refraction of radio waves.

1. Horn antenna

Horn antenna, also known as horn antenna, consists of a uniform waveguide and a horn waveguide with a gradually increasing cross section. There are three types of horn antenna: fan horn antenna, corner cone horn antenna and cone horn antenna.

A so-called "back-focus antenna" which was popular among satellite enthusiasts in the previous stage can be regarded as a conical horn antenna in essence. It rolls the iron sheet into a horn shape, makes the horn diameter 3CM and the cone angle 16, and makes it a fixed bracket with adjustable elevation angle and polarization angle, so that it can receive signals by aiming at the satellite.

The horn antenna is one of the most commonly used antennas, which has the advantages of accurate gain, simple structure, convenient use and wide working frequency band. However, it is generally only used as the feed of the secondary reflective feed-back parabolic receiving antenna (Cassegrain antenna), and it is rarely used for direct reception because of its small receiving area and small reflection coefficient on the mouth surface.

2. Flat antenna

The receiving surface of a flat antenna is flat, and the tuner is arranged inside the antenna, which is generally used to receive KU-band live satellites. According to its internal structure, common planar antennas can be divided into two types: dipole type and slot type.

(1) Oscillator-type flat antenna

Oscillator-type flat antenna is based on the principle of half-wave oscillator-type unit antenna used for TV reception in the past, except that the flat antenna is made of many half-wave oscillator-type unit antennas on a printed circuit board with a special medium according to certain rules and using microstrip circuit technology. Most of the dipole planar antennas on the market are designed for overseas markets in Korea or Japan, with a built-in 1.75GHZ or 1.678GHZ local oscillator and circularly polarized reception.

the gain of the dipole antenna depends on the number of half-wave dipole elements. The higher the gain, the more half-wave dipole elements are used and the larger the area of the antenna.

(2) Slotted planar antenna

Slotted planar antenna, also known as slot antenna or slot antenna, is a large metal plate. According to certain rules, cracks are artificially dug, and the length of the cracks is required to be 1/2 of the average wavelength of the received signal, and then a cavity is made behind the metal plate, so that electric waves perpendicular to the waveguide plane will be absorbed by the waveguide from the gap to the maximum extent.

as far as the current technology is concerned, the flat antenna can only receive KU-band signals, and can only receive a single polarization. If you want to receive another polarization, you need to rotate the antenna plane by 9. Due to the rigorous manufacturing process and high material cost, the current flat antenna is expensive.

3. len antenna

in optics, a len can make a spherical wave radiated by a point light source placed at its focus be refracted by that len and become a plane wave. The lens antenna is made by using this refraction principle, which consists of a lens and a feed placed at the focus of the lens. According to its working principle, there are two types of common lens antennas: dielectric deceleration lens antenna and metal acceleration lens antenna.

(1) Dielectric deceleration lens antenna

Dielectric deceleration lens antenna, also known as Luneberg lens antenna, is designed according to the principle of dielectric lens invented by Luneberg in 1944 (focusing electric waves through dielectric).

zebel lens is made of low-loss high-frequency medium, with thick center and thin periphery. The plane wave signal emitted by the satellite is decelerated when passing through the dielectric lens, the path of deceleration in the middle part of the lens is long, and the path of deceleration in the surrounding part is short. Therefore, the plane wave becomes a spherical wave after passing through the lens and gathers at a certain position on the spherical surface. As long as a feed is installed at the focus, the satellite signal can be received.

The LUNE- series lens antenna introduced by Sumitomo Electric and JSAT Co., Ltd. in 24.

(2) metal accelerating lens antenna

metal accelerating lens antenna is developed according to the principle of Waveguide Lens.

The waveguide lens is composed of many metal plates with different lengths placed in parallel. The metal plates are perpendicular to the ground, and the metal plates closer to the middle are shorter. Satellite signals are accelerated when propagating in parallel metal plates. The closer to the edge of the lens, the longer the accelerated path, while the shorter the accelerated path in the middle, so that the spherical wave passing through the metal lens becomes a plane wave.

CyberTenna S64 satellite receiving antenna developed by TeleWide in Sweden in 23.

The advantage of lens antenna is that the side lobe and back lobe are small, so the pattern is better. The accuracy of lens manufacturing is not high, so it is more convenient to manufacture. Its disadvantages are low efficiency, complex structure and high price.

Uncover the trick of the swindler's "receiving without a pot"

From the above introduction, you should know that it is possible to realize "receiving without a pot" by using a new satellite receiving antenna. In fact, whether it is "no-pot receiving" or "pot receiving", a set of satellite receiving equipment is composed of three parts: satellite receiving antenna, tuner and satellite receiving. The so-called "no-pot reception" or "pot reception" is just that the antenna types used for receiving antennas are different.

these new antennas have their reception limitations, which are generally aimed at receiving satellite signals in KU band, and the ground field strength of satellite signals is required to be high. In addition, especially the flat antenna and lens antenna are expensive, which is far from the ordinary satellite "pot". For example, in a satellite receiving system using a flat antenna, the price of only one flat antenna with a specification of 35×185㎜ is 4 yuan, and if you add an ordinary satellite receiver, the cost will be at least 6 yuan; However, the cost of using an ordinary "small pot" of .45m, which is equivalent to its receiving performance, plus an ordinary KU-band tuner and satellite receiver is only 3 yuan, which is mainly caused by the high production cost of these new antennas.

therefore, from the perspective of equipment production cost, there is no "pot-less receiving" equipment whose selling price can be lower than that of "pot-less receiving", which means that the cost of "pot-less receiving" is higher than that of "pot-less receiving". For the "pot-less reception" with too low price, it is obviously a trick used by swindlers to cheat and attract people to buy. Let's expose it one by one.

One of the tricks of "no pot to receive"-playing word games

Some websites advertise swindlers: "XX brand high frequency/no pot/anti-jamming indoor digital signal receiver, which is jointly produced by China and the United States, receives channel 6B of three satellites in Asia-2, 3 and Asia-Pacific 1A ..."

On the surface, the swindlers say "no pot", which makes people mistakenly think that "the pot cover is not needed. When they find them, they can justify themselves to the dupe, saying that "no pot" means no "pot cover" and only sell receivers! If you need to receive it, you have to have a "pot cover".

These swindlers who recruit "exclusive agents at all levels" mainly cheat people into sending money. They generally don't send receivers to the dupes; Even if you send it, you will send inferior receivers of tens of dollars, and then say that it is not enough to have a receiver alone, and further swindle more money into the remittance to buy the remaining "supporting equipment."

One of the tricks of "no pot to receive"-using GPS high-tech terms falsely

Many advertisements selling GPS satellite TV receivers have been posted on some streets, which said that "synchronized tracking with satellite tracker and automatic search and positioning with GPS can receive many free TV signals, and there is no pot, which is very clear and the lowest price ..."

Let us know what GPS is first? GPS is the abbreviation of "Global Positioning System", that is, Global Positioning System. It consists of 24 GPS satellites in synchronous orbit at an altitude of 2 thousand kilometers, several GPS signal monitoring stations on the ground and GPS signal receivers used by users.

the GPS signal receiver can search and capture the GPS satellite. When the satellite is captured, the signal is towed and tracked, and the received GPS signal is transformed, amplified and processed, so as to measure the propagation time of the GPS signal from the satellite to the receiver, analyze the navigation message sent by the GPS satellite, and calculate the longitude, latitude and height of the GPS signal receiver in real time. For the vehicle-mounted GPS receiver for navigation, it is also equipped with a liquid crystal display screen, which directly displays navigation information and even an electronic map on the screen to determine the position of the vehicle body on the electronic map.

that is to say, the GPS signal receiver is a kind of tracking and positioning equipment. It can't receive the satellite signal sent by the geosynchronous communication satellite over 36, kilometers. Only when it is combined with the satellite automatic tracking antenna system can it have the function of receiving this satellite signal.

a new type of satellite automatic tracking antenna measures the real-time motion parameters of the carrier through the GPS receiving module equipped inside, and after being analyzed and processed by the microprocessor, an error signal proportional to the deviation angle is obtained to control the mechanical driving device pointed by the antenna, thus realizing continuous tracking of the satellite. However, the price of such an automatic satellite tracking antenna is above 1, yuan. These scammers use GPS high-tech terms to confuse people's audio-visual and achieve the purpose of cheating.

one of the tricks of "no pot to receive"-advertisements in newspapers and magazines

In addition to posting advertisements on websites and posting illegal leaflets on the streets, scammers also use print media such as newspapers and magazines to advertise and make false propaganda in order to expand the spread of these advertisements and attract more people to buy them.

Some users reported that they once saw an advertisement in a newspaper-a satellite receiver without a pan, so they remitted money to 65 yuan to buy it. Unexpectedly, two months passed, but nothing was received. After many negotiations, we used various excuses to prevaricate, saying that it was out of stock, asking for it, saying that it had been sent, and waiting for it. Later, as soon as I answered the phone and said that I was inquiring about something, I hung up immediately; It is very patient and serious to say that it is to remit money to buy something. Moreover, there are many advertisements for satellite receivers without pots like this, which have been published in many newspapers and magazines.

These swindlers take advantage of people's belief in newspapers and magazines, believing that advertisements published in newspapers and magazines will not deceive people. These newspapers and magazines, and even some well-known newspapers and magazines, are lax in reviewing such advertisements, or they think that there is such a "no-pot receiving" device and publish it, which undoubtedly becomes an accomplice of scammers.

one of the tricks of "no pot to receive"-live fake demonstration

Some readers asked, although they also doubted the liar's statement, what is the reason why they were able to play satellite TV pictures after seeing the liar's live demonstration? Let's debunk two common cheating tricks used by scammers.

1. Short circuit of coaxial cable with RF plug

In a stall near a railway station, a small black-and-white TV set was placed on a square simple table, and a small plastic box was placed next to it. The stall owner shouted while tuning the channel on the TV set: "For sale, as long as 2 yuan, you can receive dozens of satellite TV signals." And demonstrate on the spot that as long as the plug of this "satellite receiver" is plugged into the access port of the TV set, many satellite TV channels will be broadcast immediately by the small black-and-white machine; If you don't insert it, you will get nothing from a snowflake. At his urging, many citizens paid for such a "receiver".

when the citizens take it home and connect it to their own TV sets, they can't see anything. When I opened this small plastic box, I couldn't help but be dumbfounded. This is the so-called "satellite receiver".

It turns out that the swindler used a hidden portable VCD player to burn a VCD disc with satellite TV signal content, and then it was emitted by an RF radio frequency modulation transmitter. The small black-and-white TV set in the hands of the swindler was not an ordinary black-and-white TV set, but was specially modified, and the pull rod receiving antenna lead it carried was connected in series to the tuner in the TV set through an RF jack. The so-called "satellite receiver" sold is nothing more than a coaxial cable tie rod short wire with RF plug. As long as the shell of this "satellite receiver" is opened, it can be clearly seen that the inner core of the coaxial cable is twisted with this shielding layer. The most ridiculous.