SatSig topic:

DW6000 never syncs... LNB?

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May 20^th, 2015 at 5:36am

Well I'm back again... (in 2009 I had a BUC trouble and replaced the whole TRIA...)

My set up spends all winters powered down in the cold... Doesn't help?

On my return this time, I just can't get any lock on any transponder/sat that I tried: I get broad peaks in the mid teens of Signal Strength, with some in the low 20s. And twice at 28-29, BUT these high ones can NOT be reproduced. Never once did I see a 30...

Took all the waveguide stuff apart: clean and dry. Changed coax... voltage OK... etc

What could possibly match these symptoms? I'm leaning towards an erractic old LNB... That saw too many cold northern winters. Are they known to fail that way? Erratic noise would explain all this? Are they PLL?

Thank you.

Christian

Jun 1^st, 2015 at 3:44pm

for the DW6000s, i believe the standard Hughes saturated 1W and 2Ws use a LNB that requires a 10Mhz reference vs PLL.
I have on occasion seen issues there the modem will get stuck at 15 or 30. A factory reset via the RF command would quickly tell you if that the case, but I would use that as an absolute last resort.

If your service is provided by Hughes they have been slowly migrating there carriers to DVBS2 which is not supported by the DW product line, so its possible the carrier you where on no longer compatable, If they did a transponder migration while your system was turned off, it wouldn't have received the new carrier information.

What satellite are you on?

Jun 1^st, 2015 at 10:12pm

I've copied this from a message elsewhere:

"The way the signal scale works is as follows: Initially it acts as a simple noise power meter. You get a reading when the dish is pointed at any satellite. If you move the dish along the orbit each satellite will give a reading, in range 0 - 29. This noise power readout has a maximum value of 29. If you get 29, you have peaked up on a powerful satellite.

Next, if you are pointed at the correct satellite, the correct polarisation, have the correct LNB local oscillator frequency and the config tuning and symbol rate all match up then the demodulator locks and the modem will show a receive LED light and the signal quality scale will immediately jump up to about 90 (in the range 30 - 100). Now you have your wanted carrier. Peak up."

Generally low receive signals can be caused by moisture and corrosion for long distances along inside the cable. Intermittent signals are likely due to poor/corroded connections. Try waggling the LNB cable to see if there is poor contact or loose contact inside the LNB socket.

I don't know if Hughes LNBs are PLL or DRO type.

I have come across DRO type LNBs that have failed due to a physically detached DRO pellet or LO frequency jumping about. That could be caused by extreme temperature variations. Try gently tapping the LNB while measuring the signal.

Talk to Hughes in case you need a new SBC.cfg file in case your satellite carrier was ceased or changed during the winter when you were not operating.

Best regards, Eric.

Jul 21^st, 2015 at 5:30am

UPDATE:

I had bought another spare LNB, and all 3 are working! No real idea what was wrong for a while, except I am now suspecting the little power supply!

FYI