W5 dropping out

[trinidex]

Hi guys,

My W5 signal drops periodically. I'll be watching HBO or SHO for half-an-hour with no problems and then all of a sudden the picture goes black and the DC light goes off. For a while after the picture will come back then go off, come back then go off and I can't figure for the life of me what the cause is.

My signal seems good and strong, when all is okay Strength is around 85 and Quality 75 when the picture drops Quality hits 0 but Strength stays the same.

My setup is this:

2 x DSR922
1 x 8-way LNB
12ft prime focus mesh dish
Chaparral dual fixed feed horn and 2 LNBs

I currently only have Horizontal fed into the 8-way, there is no Vert feed (purposely disconnected for troubleshooting).

I tried hooking the LNB straight to 1 receiver but the same problem occurs, so I'm thinking it is not the switchbox.

Does anyone have any suggestion as to what the problem might be?

Thanks in advance

 

[tvropro]

75 quality is way low for a 12 foot dish, my 12 foot is always 99 no matter what the weather. I would start with alignment if that don't fix it the LNB may be at fault or TI.

 

[truckracer]

My 10' dish stays pegged on 99%
Sound like however you have terrestrial interference knocking out your signal.

I have a TI problem here sometimes.

 

[trinidex]

Hmmm T.I. - what are some possible causes of T.I.?

I have another 12ft P.F. next to it that is used for G5 - CNN is crystal clear.

Thanks!

 

[trinidex]

Update:

I hooked in the Ver feed directly to the 922 used for HBO and switched to HBO West(?) - I left the other receiver on the Hor feed (through the 8-way switch) and Showtime.

Within the last hour, neither of them have dropped or gone off - weird!

Is it possible to 'overdrive' an LNB?

What about 'crosstalk' from one receiver to another? - maybe the HBO 922 is playing up or is unstable and it 'wobbles' passing back interference or some-such?!

The 8-way switch is a passive unit, getting power from the receivers.

I am sooo confused

 

[tvropro]

You could be getting some kind of intermod from some of the extra devices hooked up. This is hard to pinpoint. Start out basic and connect one device at a time till you find the culprit. Although 75 quality is acceptable it's more like a 7 foot dish would get so peaking the dish wouldn't hurt. Sometimes keeping it simple is better

 

[sergei]

Has this always been a problem with the setup your using? I have a different setup that was given to me by a Chaparral engineer and that's why I'm wondering how long you had this drop out issue.

 

[trinidex]

I'll try peaking and see what happens, it could've shifted off beam I guess - I can't remember how high I was able to peak it before.

This problem has only started since I switched from X4 to W5 - I didn't notice it at first - I travel a lot so didnt get chance to watch much of it, the missus used to tell me it was dropping but everytime I checked it was okay.

The setup is identical accept of course I'm using a different dish with different LNBs, everything else is the same - oh and of course I've told the 922s they've got C-Band LNBs attached, not Ku


Thanks one & all

OOPS - almost forgot to mention, since my re-arrange earlier the system was stable (both pols) for over an hour, then BAM! break-up occured, and it occured on both POLs - so we're now here (I'm guessing):

1) Both LNBs bad - not likey, but possible
2) Dish out of alignment - how does it work great for a while then drop, then great again?? (scratches head)
3) Cabling (dear gawd I hope not!)

 

[tvropro]

I'll try peaking and see what happens, it could've shifted off beam I guess - I can't remember how high I was able to peak it before.


1) Both LNBs bad - not likey, but possible
2) Dish out of alignment - how does it work great for a while then drop, then great again?? (scratches head)
3) Cabling (dear gawd I hope not!)

Try alignment, If you still have an issue I would say it's a source of TI or #3

If it's a mild TI having it at the maximum satellite signal you can get may be enough to overide the TI. You should get 99 Q with that size dish. Make sure the feedhorn is centered, the F/D, focal length and declination are correct, then peak the azimuth, elevation.

 

[sergei]

From this line in your posting it sounds like everything from the receiver out is different

The setup is identical accept of course I'm using a different dish with different LNBs, everything else is the same - oh and of course I've told the 922s they've got C-Band LNBs attached, not Ku

What type feedhorn are you using...it sounds like a dual c-band because of the KU statement, is this correct.

 

[trinidex]

What I noticed lastnight was that my Sig was at 78% and my Qual fluctuates between 88% and 99% on HBO - which is directly fed from the dish.

Clarification on my setup...
When I said "setup is the same", what I mean was, the cabling, switch and receivers are the same, the only difference is the dish, feedhorn and LNBs.

The feedhorn is a dual fixed c-band horn, with 2 lnbs one for H and one for V

I replaced one cable that feeds HBO directly, brand new, laid it out yesterday evening, same problem occurs! - So cable is out (phew!)

I guess it must be either T.I. (still none the wiser on that!) or ???

When the signal drops, both LNBs suffer and they are not linked electronically, only physically bolted to the same feedhorn.

 

[tvropro]

The best advice I can give is give it a good alignment and see what happens. TI (terrestrial interference) can be hard to deal with. Methods of dealing with TI include filtering and screening. This can get into a long drawn out process even if you have the right equipment and know what your doing.

Here's some info on TI: Satellite Footprints by Dish Size - Noise Discussion, Terrestrial Interference (TI), Rain Fade, Free Space Loss, Earth Thermal Noise Chart, Side Lobe Maps, Conflicting Frequency Chart

 

[sergei]

Other than you may need to adjust your dish and that maybe all it takes to fix the problem. If it was T.I. or an adjustment with the dish then I would think you should see more picture breakups

I still have some question.

1) Does this happen on all satellites?

2) Does this happen to both receivers?

3) Are both H and V affected?

4) In the receiver setup did you select the Dual C-band LNB option?

The TI which is terrestrial interference is normal caused by a nearby radar system and normal the interference will match the sweep of the radar. I'm not sure about some of the newer military radar that has no rotation, maybe someone else knows.

 

[truckracer]

I get bad TI on my western sats during the afternoon. It kills everything c-band from Amc-8 to satmex. Totally mutes HBO/Max on G1 (G15).

I thought about buying one of those TI filter wave guide chokes that goes in between the lnb and feedhorn. I have an orthomode feedhorn with dual c-band lnbs and dual ku lnbs.

I would have to have two chokes. Big $$$$$$ we are talking there.

 

[trinidex]

1) Does this happen on all satellites?
Although motorised, I don't use it on other sats so I don't know - the sensor that reports movement is damaged.

2) Does this happen to both receivers?
Yes it does.

3) Are both H and V affected?
Yes they are, and they are physically seperate.

4) In the receiver setup did you select the Dual C-band LNB option?
Yes I did, one polarity on the top, the other on the bottom.

Other than you may need to adjust your dish and that maybe all it takes to fix the problem. If it was T.I. or an adjustment with the dish then I would think you should see more picture breakups

I still have some question.

1) Does this happen on all satellites?

2) Does this happen to both receivers?

3) Are both H and V affected?

4) In the receiver setup did you select the Dual C-band LNB option?

The TI which is terrestrial interference is normal caused by a nearby radar system and normal the interference will match the sweep of the radar. I'm not sure about some of the newer military radar that has no rotation, maybe someone else knows.

 

[trinidex]

It's not really fixed but this is what I did today...

I tried re-aligning the mesh dish, slight movement up/down and left/right, also skewing the feedhorn. The only thing that happened is loss of signal, it never got better.

In desperation, I dug out a CBand LNBf with a feedhorn for an offset dish and installed it on my 8ft solid (that I used to use for X4).

I've been watching TV all evening - just finished "Fried Green Tomatoes" - (man that movie goes on for ever!) and the signal didn't drop once.

The only downside to this is that I only have LNB and so only 1 polarity at a time.

I've been in touch with Mike Kohl and he is organising the proper bits for my 8ft so I can get both pols at the same time.

Thanks guys!

 

[sergei]

If you haven't already tried this then here's something else to to, hook both your H and V directly to one receiver ...nothing else in line.

 

[trinidex]

Yeah I tried that, both Pols exhibit same issue, both rcvrs losing signal at the same time

If you haven't already tried this then here's something else to to, hook both your H and V directly to one receiver ...nothing else in line.

 

[sergei]

Next question how do you have the feedhorn positioned.... at what clock position?
How about the F/D position? Did you get instructions for setting the F/D for the feedhorn.
How about a picture of the dish and feedhorn....night help us.

 

[Corrado]

Another thought that comes to my mind is water intrusion into a cable connector or fitting. I once had an LNBF that had condensation inside that caused problems as it would come and go. That gave symptoms of heat or cold sensitivity.

Dissimilar metals in connectors and couplers sometimes react and corrode internally causing high resistance and signal degradation.

You could test the cables by disconnecting both ends and testing continuity with a meter for shorts. Sometimes all it takes is a single stray strand of shielding caught under a fitting.

If all else fails, try another spare piece of cable laid out direct to the dish for a test if the cable is buried and possibly damaged.