Problem on my C band Need some Ideas.

[gregom]

Hi guys,

I hope some of you guys may have the answer for my problem.

I own a 12' HH dish with C and KU LNB's, I am using a corotor II plus feedhorn. I currently use this dish to catch all north American and Atlantic satellites. Last week my C Band Image started to be braking out.

It got to the point that i couldn’t watch TV anymore. I took a walk to the Dish to see what was happening outside. The LNB was very hot therefore i disconnected everything, after a few day i tried to see how was my c band and i couldn't see anymore picture on analog, my LNB got burned.

I recently bought a NORSAT DRO series LNB +-150Khz with 15K noise figure. I connected everything up and I was able to see all my pictures again. However after 3 hours my signal started cutting out and I lost everything Again.

I have tried the following:

1. I changed the feedhorn and the same behavior happens.
2. I have tried all satellites on KU and my picture does not brake like C.
3. My dish is on the ARC for sure because i was able to catch from satellite 22W to 137W.(C and KU)

What i have noticed is that the level on my digital side of the C band is oscillating like crazy, and before it wasn't. Whenever I have this oscillation my pictures starts to chop. I have also noticed that on C band analog the picture has some horizontal lines within 2.5" apart along the TV screen. These lines appears only when the picture is breaking in digital.

I have replaced cables, Feedhorn you name it. what could be wrong with my system ? would it be possible that my LNB L.O frequency is a little out ? or that the LNB is defective ?

Any help is appreciated.

Gregom.

 

[Lynskyn]

I would suspect either the C Band tuner in your receiver has issues or possibly you are experiencing terrestrial interference of some kind. Does your receiver have a TI filter built in?

 

[chefwan]

have you replaced the coax from the dish to the receiver? it may be arcing and causing ur signal to go in and out .

 

[gregom]

C band Issue

Guys,

I tried using a shorter cable right beside the dish and i still have problems.

When i use my T1 filter the picture get worst.

In regards to the tune, I have tried 2 different receivers on the digital side, connecting straight to the dish without the analog receiver the problem still persists.

I have no clue what this might be... however on the KU i have no issues what so ever. This at least tells me that the dish is properly lined up and that my feedhorn and polarizer is working O.K.

My concern is why am i getting those horizontal lines on the analog side ?

If i eliminate them my LNB behaves excellent on the digital side. Would it be possible that the LNB is malfunctioning?

 

[Lynskyn]

Try a known good C-Band LNB. If you still see this issues with the horizontal lines you probably have some kind of interference.

 

[gregom]

Isn't Norsat a good LNB ? The lnb that i am using is the DRO8000 series model # 8115, fairly expensive LNB.

If not... what is a good LNB out there ?

 

[turbosat]

Norsat is one of the best so I wouldn't suspect it. You don't say what kind of receiver you're using, they're all getting pretty old now.. May have some bad capacitors in your receiver. You say its doing things on analog channels too, so I wouldn't suspect the descrambler circuits (not at first anyway)
Without seeing it thats my best idea, receiver and/or cabling. If you're near an airport or an air force base with radar , you prob would've had problems before now. There are other forms of terrestrial interference, like microwave transmitters (any new cellphone towers close by?)
I'd try another reciever first, see if it has problems with your system. Also, if you haven't already, you can trade out the cables from ku to c-band side, and see what happens to both freqs then, to eliminate the cable as being problematic.

 

[Lynskyn]

Isn't Norsat a good LNB ? The lnb that i am using is the DRO8000 series model # 8115, fairly expensive LNB.

If not... what is a good LNB out there ?

No, I meant a known working LNB to eliminate that as being the issue. The Norsats are very good - I use those myself.

 

[gregom]

Let me give more information here;

I have tried another cable and the problem is still there. I switched the KU cable to the C band and the horizontal lines are there still.

I tried connecting straight to my Topfield 4000PVR digital receiver and the picture quality is bouncing from 0 to 87%. Only on Nasa channel the picture remains on. Since the signal is so strong... (I had all channels working before and now i can only get Nasa and a few others, without problems)

On the analog side I use a General instrument 550. This receiver is quite old but still works OK.

I live in town and there are no cell phone towers installed or no overhead wires. the dish is about 14 feet up in the air and has clear view on both of the horizons, since i catch signal from 22W to 137W.

I know for sure if I can eliminate those lines my problem goes away.

When my satellite was working for 3 hours I had no horizontal lines on C band, and in the digital receiver the level line would not fluctuate like it is now.

My level in the digital receiver is also jumping between 77 to 82. It should remain constant like before.

I also tried to use my pansat 2700 receiver and the problem remains there.

I found a very old LNB here in my house, I tried it and the horizontal lines are still there.

I just can't figure it out what the problem is.... my KU band works fine on digital. So at least my feedhorn and dish are properly aligned.

I have also switched the cables from C and KU and the problem remains on C band. Therefore the Cable is fine.

I don't know what else to do. I believe that this LNB from NORSAT is a great LNB but if the LNB is working O.K what might be wrong with my setup ?

Would a C band interferance Filter help me ?


Gregom

 

[Lynskyn]

A TI filter might help. It seems logical to me that it is something interfering with 3.7-4.2 Ghz since your Ku is fine. It sounds like you have eliminated everything else. Is there anything else new in your environment? Sometimes things like lamps, bug zappers and battery chargers can even cause issues.

 

[gregom]

There is nothing really new... I am think to buy a band pass filter and put between the feedhorn and LNB ...

Do you think this is my best bet ?

The TI filter in my receiver makes the picture worst ... why is that ?

This is very strange ... i ran out of options ....

A TI filter ... do you know where i can get that ?... I will place an RFI filter on my tv and see what happens ..

I have just noticed that my C band level droped from -33 to -40 .... this is weird ... it looks like something moved outside ... I have lost some of my signal strength.... i will move the dish up and down and see what happens with the signal ... But i think the feedhorn might moved a bit.

Thanks

Gregom

 

[gabshere]

i'm not the expert on co rotors but is it possible the lnb in reversed. i know it will reverse the polarity , which for digital channels they will still come in but on the analog channels it will give you the horizontal lines like you mentioned.

 

[gregom]

No it is not reversed ... my digital picture is all choppy and i can get c band analog but the picture has these horrizontal lines that i have no clue why ...

As I mentioned before ... my c band analog signal has dropped its strength ... so i have to investigate that ... meanwhile when i first installed it all worked for 3 hours without any problems ... up to now ...

The wind was calm and the dish did not move at all ....

Maybe a filter might be the solution but i still think that the filter will not help me ... this is weird but i can't find a solution yet ....

Gregom

How can I load some pictures here ... I took 2 pictures ... one from the digital and analog reception on my TV ...

 

[gabshere]

when you type a mesage goto the advanced window and manage attachments ( also its a mountain pic onthe mini toolbar if you already have a host) but its easier to goto manage and upload that way

 

[gregom]

Here are the pictures:

The first one if from the digital NSS806 C Band and the other is satellite 135W

As you can see there are some horrizontal lines on C band analog and the picture on digital is completly funny.

Has anybody seen anything like this before ?

Gregom

 

[turbosat]

This is a tough one to crack!
What satellite are you getting NASA from? You said it was still coming in ok for you. (when surrounded-attack in all directions)
EDIT>diregard - posted at the same time you were posting the pictures

 

[turbosat]

Tell me which channel on 135w so I can look at it here. I didn't know there was any analog left on those western sats on cband.

 

[gregom]

Turbo

I get nasa on satellite AMC6 72W before I was able to catch on AMC6 and AMC7 but since i got this line i am unable to catch the other Nasa channel from the west coast satellite.

The channels I was looking on my C band analog is channel 5 on satellite Galaxy 15 133W Horizontal POL.

See if you have those lines... I bet you will be ok ... I get those lines on all C band analog.

Gregom

 

[turbosat]

Yes they all look fine here, shopping channel clear as can be, ARTS and the EWTN channel , fox news is back I see and its good too.
Is the GI 550 what you are getting the analog signals thru? If you're filtering thru switches and pvrs or vcrs its possible something else is throwing in that annoyance.
I have a 550 also, and GI650 that Im using for analog, they both are super receivers.

 

[gregom]

Yes they are good receivers ...

I am connecting straight from the dish to the receiver (there is absolutly notthing in between) and Before i was catching -33 and now my signal is -40 ... What is your signal and what dish are u using ?

something funny is happening here ... I know those numbers because I was outside for 3 days playing with my feedhorn to get the best possible output signal.

I don't know if you have a voltmeter, but can you check the continuity and tell me the result you get from the C band LNB ?
I don't know if you can disconnect your C band and check it for me ... mine reads 707.

thanks

Gregom