Dish Network: LNB Drift Detected (DVR 625)


Tue 06 Jan 2009 08:00:00 -0800

At home, I’ve got a Dish Network DVR 625 connected to a Dish 500 on my roof. Recently, my satellite setup started experiencing some strange signal quality issues: splotching, broken audio, and in some cases the unit loses the satellite signal all together. There are no large tress or other objects that block my view of 110°W and 119°W, so I started hunting around for answers. I ran the DVR 625’s self-test feature, and luckily, it helped me pin-point the problem. Based on the self-test results and my own investigation, I’ve concluded that I have a potential problem with the Dish 500’s LNB Low-Noise Block Converter on the roof.

The LNB is a parabolic receiver (an antenna) which converts a high-frequency satellite signal to a lower one that can be easily sent over coaxial cable. An LNB Drift indicates that the LNB’s internal oscillator frequency is operating out of normal range, and therefore, it could not compensate for any normal fluctuations with the incoming satellite signal. This explains my signal quality issues; the LNB hardware is failing. On my DVR 625, the self-test reported an LNB Drift of about -6. Many online forums and other sites suggest that an LNB Drift might be caused by a failing LNB, a bad parabolic dish, or a blockage of the incoming satellite signal. In my case, I think it’s pretty clear that a failing LNB is the most likely cause.

I contacted Dish Network Technical Support for help — they told me that they would only send a technician to my home to replace the LNB if the LNB Drift was less than -8 or greater than +8. However, after some more digging, I found this interesting internal Dish Network memo that discusses failing LNB’s and Dish’s LNB replacement policy. According to the memo, Dish should replace the LNB if the drift is +/-5. Well, my drift is -6 and sometimes -7 (depending on the time of day) so I guess I’m due for a replacement.

The failing LNB on my roof was eventually replaced, and all is well again.