Causes and solutions of poor satellite signal reception

In debugging satellite TV or in use, it is often found that the received signal quality is not good, and its performance is as follows: 1. The signal is intermittent and the screen sometimes has mosaics. 2. The picture jitter is unstable, and sometimes the upper and lower pictures appear. 3. Disconnected, the signal was erratic. 4. The sound is intermittent and the sound is turbid. When these phenomena occur, some people tend to focus on the satellite, thinking that the antenna is not aligned with the good satellite, and spent a lot of time to adjust the antenna, but the result has not been resolved. In fact, there are many reasons that affect the signal quality, and it should be analyzed, one by one to eliminate various factors, in order to be satisfied with debugging and reception.
During commissioning, first of all, the supporting equipment must be carefully inspected, and every link in the commissioning and installation must be paid attention to. It should not be rushed to achieve success. It is necessary to understand and confirm the impact of the local environment on the quality of the received satellite signals. So as not to give up the previous achievements.

1. Inspection of equipment

1. Digital receiver: stable and reliable work, good after-sales service and brand reputation should be selected, it is best for beginners to choose a receiver with signal strength display, lower threshold, and superior image quality. The function may not be very good. , It can be practical. Receivers with high thresholds often fail to receive signals when watching weak signals. Especially when the margin of other equipment is not very large, the threshold of the receiver is very important. For example, in the same supporting equipment, different quality is used. Receiver, poor receiver can not receive when receiving weak signal, or the picture is unstable, there are mosaics and so on.

2. Antenna: The antenna is a key supporting equipment that affects the quality of the signal. The accuracy of the antenna is very particular. The antennas of different brands vary greatly in their pros and cons. The antennas of poor quality or deformed, even if the antenna caliber is very large To no avail, the focus did not know where to go, but the results were not adjusted well. Such examples have been heard. In order to ensure excellent signal quality, it is not appropriate to choose an antenna to blindly pursue a small aperture or a superstitious aperture, but to pay attention to the accuracy and quality of the antenna pot surface. As long as the antenna aperture meets the receiver threshold requirements for received signals, it is sufficient.

3. High-frequency head: The quality of the low-frequency high-frequency head is difficult to guarantee, and each batch is different. The quality problems of the high-frequency head are mainly reflected in the unstable working performance, such as local oscillator frequency drift and poor thermal stability. , Poor consistency of the frequency band, low gain, etc. In use, the signal will be unstable, if it is looming, some frequency bands are good, some frequency bands are poor, or even not received, the low-gain high-frequency head, the received signal The quality is obviously not good. The author has done experiments, using the same antenna and receiver, receiving the same program, and replacing the tuner of different brands one by one, but found that the quality is different, even in different batches but in the tuner of the same brand There are also differences. Seriously unqualified products with a local oscillator drift of 50 MHz have also been found. Therefore, it is necessary to understand the quality of the high-frequency head used during commissioning. It is best to check it first.

4. RF cable and F connector: Although the cable and the F head are not critical equipment, if they are used improperly, they will also affect the quality of the signal. If the core wire of the radio frequency cable is too thin and the shielding network is too thin, the leakage and attenuation of the signal will be large, resulting in the degradation of the signal quality. The connection between the F head and the cable should also pay attention to the process. If the connection is not good, the shielding net and the core wire will be short-circuited, or the shielding net and the F head will be disconnected. If the waterproof treatment is not good, the wind and rain will cause oxidation. , Poor contact with the high-frequency head caused a significant drop in signal quality. In addition to choosing high-quality cables and F-heads, we must pay attention to reliable connection and rain protection.

5. Various switching switches: when multi-star or multi-home receiving is needed, switching switches are needed, such as: 0 / 12V, 13 / 18V voltage switching switches; 0 / 22KHz, DiseQ switching switches; various power points Device, wire and so on. The quality of these switches is variable, and the poor quality of the switch has a large signal loss, which seriously affects the quality of the ratings. Choosing a good switch is also very critical.

In short, the reasons for the deterioration of the received signal due to the poor material of the device are very common, and compared with high-quality equipment, the quality of the received signal is immediately reflected, and some people are concerned about these small auxiliary equipment and equipment. The tuning process is often negligent. It is difficult to tune the stars for the first time, so you should calmly think about whether these are the reasons.

Second, installation and commissioning

1. After selecting high-quality equipment, the accuracy of the star is the first step in determining the quality of the received signal, so you must be patient, especially for the first-time adjuster, unfamiliar with the prescription, and lack of experience. You can use some auxiliary equipment for star adjustment, such as: compass, star finder, inclinometer, etc. For experience in this area, it is best to read some articles about electronic publications, such as "TV Media". These newspapers are the best mentors and friends. You must have the knowledge and experience you need most.

2. Try to avoid debugging on cloudy and rainy days when searching for stars. Bad weather will cause a great loss of signals. You should also know whether there are sunspots during debugging and whether the clouds are too thick. Another thing to note is that even if the debugging is carried out in clear weather, the signal strength of the location of the transmitting signal source will be affected, or the signal strength will be affected, or if the debugged transponder is stopped, or the parameters have been changed, etc. Although this situation is rare, it sometimes coincides. For those who are inexperienced for the first time to adjust the star, they can use the time slot method or debug other transponder programs.

3. During the debugging, the shielding objects in front of the antenna should be avoided, such as houses, trees, etc. After the general orientation can be determined with a compass, the distance of the shielding objects in front of the antenna can be visually observed.

4. During debugging, a group of transponders with the strongest signal in the satellite should be selected. After receiving the signal, fine-tune it to the best point, so that the weak signal can be watched satisfactorily.

5. During debugging, microwave interference nearby is sometimes encountered, mainly in the C-band. In the frequency band of 3.4-4.2 GHz, various microwave signals do exist. When debugging, the frequency of this group of transponders When the frequency of the transmitted microwave is close, interference will occur, which is usually called co-frequency interference. In this case, the signal cannot be downloaded. The only solution is to add a metal shielding net in front of the antenna to absorb the interference wave. With isolation, if the effect is not good, you can only give up.

The various reasons for the above analysis are often encountered during commissioning, so it is necessary to analyze carefully, eliminate one by one, and avoid detours.

Among the small antennas, it is preferable to use the rocker to adjust the screw to change the azimuth and elevation angles. Because the rotation is smooth, stable and flexible, the debugging is not only easy, but also the accuracy is guaranteed. Unfortunately, such antennas are rare. It is not easy to buy, you can only choose the ones with better quality from the brands of common antennas, slowly braid the antenna with your hands, after coarse adjustment to the signal, and then slowly and finely adjust, fine adjustment of the azimuth angle, you can use sets The wrench or movable wrench slowly changes the tightness of the left and right fastening screws (used to fix the back of the antenna to change the azimuth angle). Fine adjustment of the antenna is achieved by changing the tightness of the left and right thread pitch Azimuth angle until the received signal is the strongest and the picture quality is the best. At this time, the azimuth angle of the antenna should be relatively accurate. To fine adjust the elevation angle, you can put an inclinometer or protractor on the antenna, you can directly see the degree when changing the elevation angle, until the signal is strongest, and finally tighten the screws for fixing the antenna.

After the star-finding debugging is completed, rain prevention should be considered. Rainwater is one of the main killers that cause attenuation to the signal. To prevent rain attenuation, you can refer to several methods previously introduced in this journal. The simplest method can use plastic bottles. For example, a 2 liter beverage bottle, etc., cut the bottom of the bottle into a diagonal shape and put it on the high frequency head, so that the rain cannot fall on the high frequency head, but when there is too much rain on the pot surface, the signal attenuation is still very large, you can Make a rain shield on top of the antenna. If the balcony has space, you can also move the antenna into the balcony. The ceiling of the balcony can block the rain. var check_allow = "/d/Api/iscantalk.html"; var add_url = '/ d / article / write /'; function CheckLogin () {now_uid = ''; var ElecfansApi_checklogin = '/ webapi / passport / checklogin'; var logout_url = "{: U ('Login / logout')}"; var logout_url = 'http://bbs.elecfans.com/member.php?mod=logging&action=logout&refer=front'; $ .get (ElecfansApi_checklogin, function (data, textStatus) {if (data! = "") {EchoLoginInfo (data); CheckEmailInfo (data); data = $ .parseJSON (data); now_uid = data.uid; / * var login_content = 'write an article