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Jul 29th, 2008 at 6:29pm
Three guesses:
1. Severe dish mispointing and small satellite movement. If the satellite is somewhere down the side of the beam you will lose transmit connection into the hub when the satellite moves even slightly in the wrong direction. At the same time the measured receive quality will be deteriorated. Measure the receive quality every hour for a whole day. Does the quality dip in the evening ? If not, wrong guess !
2. Effect of temperature on the LNB. If you have a DRO type LNB this is fine for big outlinks like 27.5 Msps, but if you have a narrow 1 or 2 Msps outlink then the frequency accuracy of the LNB may cause the modem to lose lock on the outlink. There may be a local oscillator sweep range parameter that can be adjusted, or maybe set the nominal L band receive frequency biased one way a bit. DRO LNBs have a frequency accuracies of as much as +/- 3 MHz, allowing for both long term drift and extreme temperature limits. Look in the iSite Config Remote Receive. I think there is an LNB LO stability parameter. If you can measure the tuning stress, do this every hour during the day. When it goes beyond the limit there will be complete failure and it will start searching.
3. Water/moisture in the feed or cables. During the day it is hot and water evaporates. In the cool evening the water condenses.
Best regards, Eric.
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