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Hebei Industrial Dissection Use double Han-card friend DV B Dream software are not familiar with the software running smoothly, CPU Occupancy rate is low, not easy to hang, look for stars with high sensitivity, is a rare quality software. And other two-card player than the Han, DVBDream have its own unique advanced scanning functions, the following to talk about the DVBDream software applications related to advanced scanning features. DVB Dream Senior scan interface Shown to DVBDream advanced scanning interface check "activate close scanning" and "close to the maximum scanning signal", it can be "close scanning option" set. System default maximum interval and the interval between adjacent scanning were 2000kHz (2MHz) and 250 kHz (0.25MHz), these two parameters can be arbitrarily modified according to actual needs. "Scanning near the largest interval" can determine the frequency of a following line in the center of the scan range, if we do not know the existence of high-frequency first local oscillator, frequency offset LNB need to shift the natural frequencies of the qualitative, may the value Set a large number, or when high-frequency first local oscillator frequency offset value is large, it will not scan the results. "Interval" refers to 0.25MHz as a new parameter every scan point, the high frequency characterization of the first local oscillator frequency offset, you can set this value larger, so that you can reduce the scan time, such as high-frequency head adjust the oscillator frequency, in order to ensure accuracy, the value can be set smaller, generally you can use the system default of 0.25MHz. Determine LNB local oscillator frequency offset In Satellite TV Receive practice, sometimes receiving a signal, adjust the antenna and feeding system, no matter how, the total appears objectionable Mosaics Phenomenon, experienced friend would often transfer large or downlink frequency appropriate adjustment is small, the results of this signal can be properly received, the reason both of which were factors that parameter is not accurate, it may be because high-frequency first local oscillator frequency shift occurred. Sometimes, the first local oscillator frequency offset high frequency more than the number of machine fault-tolerant downlink frequency range, you can not receive signals, and therefore do not know that the LNB is the natural frequency shift of the real damage was already In this case, can use the advanced scanning DVBDream the first local oscillator frequency to high frequency shift for qualitative analysis. There are two cases in the scan, a scan is a parameter with DVBDream, scan the maximum frequency point and down the same frequency. For example, Asia-Pacific 2R satellites scan Tibet TV 12374V5660 parameters, default values using the system scan, the scan range of 12374 ± 2MHz (12372-12376MHz), each interval 0.25MHz scan once, scan the results of the maximum frequency point for 12374MHz. At this point, in determining the precise downlink frequency parameter case, should not happen that the LNB local oscillator frequency offset. Another is the maximum frequency point of scanning a downlink frequency than large or small, when the first local oscillator frequency may determine the frequency shift occurred. LNB local oscillator frequency adjustment LNB LO frequency shift took place, often using digital machine slowly adjusted to restore the specific operation, need to observe the number of machine side signal strength and signal quality indication, side adjust the tuner's local oscillator frequency adjustment screw, it is difficult to determine what the number of local oscillator frequency offset, operate are more troublesome. If using DVBDream can easily head to the high-frequency vibration frequency of the deviation of the quantitative adjustment. 2R satellites following the Asia-Pacific Tibetan TV 12374V5660 parameters, for example, introduced the use of DVBDream LNB LO frequency adjustment method. First high-level scanning interface into DVBDream software will scan the largest interval is set close to 25 MHz, interval set to 1MHz, according to Save the Apply button and exit, for scanning. When scanning is complete range of visible scan 12349-12399MHz, show the maximum frequency point 12351MHz, then the vibration frequency offset 12374-12351 = 23 (MHz). LNB LO frequency is nominal 11250MHz, the actual local oscillator frequency is 11250 +23 = 11273 (MHz), the head of the natural frequency of the frequency shift up a 23MHz. Remember that this vibration is 11300MHz Ku-adjusted 11250MHz first time, reducing the natural frequency of 50MHz to counterclockwise rotation of the adjustment screw about a lap and a half, this figure is rotating the adjustment screw ring oscillator LO frequency is about 33MHz , rotate a quarter turn of the natural frequency variation is about 8MHz. Adjustment screw clockwise to adjust the vibration to the natural frequency, counter-clockwise to adjust to the natural frequency decreases, the natural frequency of upward shift of 23MHz, the LO should be close to three-quarters of the adjustment screw counterclockwise rotation circle, adjusted to the approximate location and then scan, fine-tune the frequency until the maximum point of scanning the same frequency with the downlink, may think first of the high-frequency vibration frequency of the basic adjustments have been precise. Such as scanning a maximum frequency point 12395MHz, then the head of the high-frequency vibration frequency offset 12374-12395 =- 21 (MHz), the actual frequency of this vibration should be 11250-21 = 11229 (MHz), that is, the LNB LO frequency downward shift of 21MHz, the LO should be the adjustment screw clockwise no more than three quarters of the circle, further detailed scanning, adjusting, so that high-frequency head vibration frequency close to the nominal value. These conclusions through Ku-band LNB series of experiment, interested friends may wish to try the. It is noteworthy that, in high frequency when the first local oscillator frequency adjustment, the selected downlink frequency must be accurate, because the downlink frequency to as the base, and scan the maximum frequency point of comparison, if not accurate adjustment will be affected The natural frequency accuracy, so the best use Channel Operation Downlink frequency data supplied. 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