How to use the booster.
Booster is a device to amplify the radio signal. The TV screen is not always something better that you use a booster. To properly use a booster is required for a digital field strength meter and technical sophistication.
Basic usage of booster
35dB-90dB[μV] is necessary for the signal strength in the antenna terminal of the television to receive the terrestrial digital broadcasting well. When the signal becomes small more than this range, it is necessary to amplify with the booster.
The booster is the one basically using it right under the antenna.
Especially, if the booster is not used, the booster is used for a place near the antenna right under and the antenna in the weak electric current field region when an enough voltage of the antenna terminal is not obtained. The noise might increase if the booster is not amplified before the loss and the mixture distribution loss in the cable occur.
The ratio of the signal and the noise is called S/N ratio, and the ratio of S/N of the input and S/N of the output is called NF (noise figure). There is no unit because the S/N ratio and NF are ratios. It shows by decibel (dB) usually. Therefore, NF of the ideal amplifier is 0dB.
The loss occurs by the cable and the connector, etc. if the booster is not used when a weak signal is received, and the signal becomes small fast. NF worsens to the extent that it attenuates because the amount of the noise increases relatively when the signal becomes small, too.
When NF worsens once, NF is not improved no matter how it amplifies with the amplifier of the ideal. I think that an important thing to amplify before it attenuates is understood.
The booster basically does the usage that makes amends for the loss beforehand.
The booster might be necessary also in the strong electric field region. It is 30dB[μV] of the television in the terminal when there are 20dB20dB distribution loss. the loss in the cable in case of 70dB[μV] each other the signal strength in the output of the antenna for instanceWith this, it is not possible to receive it well.
For this case, the booster amplified by 20-30dB in front of before the loss occurs or the distributor is put. It is necessary to output 100dB[μV] if it puts it right under the antenna.
When you use the desk-top type booster
When the signal of the antenna is very strong in the strong electric field region or the signal in the antenna terminal after it distributes it is weak, you might use the booster of a desk-top type. When the signal of the wall terminal of the apartment house and the apartment is weak, and has poor TV reception, the usage of such a booster is effective.
It is necessary to defend a proper input and the rated power of the booster.
When details of the manual of the booster are seen, the range of a proper input and the rated power are written in the booster. It is likely to have the opposite result to what was intended if this is not defended when the booster is used to not only effective but also the return.
When the signal is not entering a proper input range large, the attenuator (ATT) is used for the input. The output adjusts the gain so as not to become exaggerated ratings. Because the signal of the antenna might change, it is adjusted that it enters in the standard even if changing in expectation of room.
If neither a proper input nor the rated power are defended, the intermodulation is generated, and the wiper obstruction is generated in an analog television. The signal quality (BER and MER) might become bad for the digital signal. If BER (bit error rate) is 2.00E-4 or less (2.0010-4), it is possible to receive it. It is a standard that the reception becomes excellent 25dB or more MER (modulation error margin ratio).
Method of selecting CATV booster (To receive the terrestrial digital broadcasting)
It is necessary to insert the CATV booster before it distributes it and, in this case, to make amends for the distribution loss by 4-8 distribution from CATV to each room because the electric wave weakens considerably. In this case, the CATV booster for the descending amplification is used.
When BS and the CS signal are mixed with the same coaxial cable, the CATV booster for the descending amplification that amplifies BS and CS is used. It will be easy for the choice of the model that can feed power to use the plus 15V also for the BS antenna.
The descending regeneration of signals of the CATV booster uses the one corresponding to 70-770MHz. Because this bandwidth is amplified almost flatly, it is the best for the amplification of the CATV signal and the terrestrial digital broadcasting. Then, it is necessary to note it for CATV because it is not, and the booster for U/V/BS/CS for usual antenna amplification doesn't amplify the CATV channel.