Satellite Signals can someone explain

AndyPet57

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I am totally confused as to how satellite signals are received and shown on the TV.

Reason behind this is if I quote a recent example of our problems

Lose BBC1 channel - saying no Satellite signal received switch box off etc etc

yet all the other BBC channels we were receiving.

Similarly now lose BT Sports channels 1 & 2 lost, and BBC 1 lost yet Sky Sports, BBC2 etc are still being received.

Getting that loss of signal message gives an impression that there is a fault with the dish, yet when going into system testing the signal strength shows as being good.

Hence our confusion - is it transmission or hardware - why do the BBC channels as the main example fluctuate.

Taking this one step further we receive our local BBC as BBC SW, we get problems with this as mentioned, if I switch to BBC South I also get problems, yet if I switch to say BBC Midlands I get a perfect picture

Please help me to understand

Thanks
 

Lazarus

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The symptoms you describe are consistent with failing Power Supply Smoothing Capacitors in your Receiver.

It's a very common problem and there are repair kits available or you might be able to get BSkyB to provide you with a replacement Box.
 

hvdh

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Tivù can you elaborate what exactly goes wrong, I suppose certain transponders won't lock any more, is it when DVB-S2, or when 8PSK ?
 

Lazarus

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No idea.

Just know that it does - and always has: In the early days, Grundig SD Sky Boxes were prone to losing Channels then in recent years it's (chiefly) the Thomson HD Boxes.

Also, the use of cheap, poor quality Electrolytics affects other Boxes, eg The Humax Foxsat and Foxsat HDR.

Repair kits are available for each affected Model.
 

hvdh

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Yes I'm curious. :)
 

Lazarus

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I'm sure you can find more if the quest for the whys and wherefores if not sated!
 
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Archived-1

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I once had a similar problem to this in the end it was my dect phone ?
 

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DECT tends only to interfere with L Band signals at around 1880 MHz (which translates to Satellite Transponders adjacent to 11532 MHz and 12480 MHz). To that extent, DECT interference is systematic, not random.
 

hvdh

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Interesting. Well, my old Dr.HD F16 (probably Technomate 6900 HD combo in UK) has these two 1500 uF 10V bulging caps.
It started gradually having trouble with certain 8PSK transponders. Now using the identical C-Tech 5000 HD Combo Plus.

These PSU capacitors are perfect time bombs to make sure most people buy new receivers after warranty expiry!
But too bad, a decent successor for F16 and the like has not shown up yet!
 

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AndyPet57

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Tivu - many thanks, my own feelings before your reply was something was breaking in the box - its old now, so time to change it
 

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Ah, just realised this query is closely related to this other Topic
 

pgh13

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As an aside, this capacitor problem isn't confined to satellite boxes.... I had to replace some capacitors to restore normal operation on a fairly expensive graphics card and friend had problems his american style fridge/freezer; again, capacitor related
 

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As an aside, this capacitor problem isn't confined to satellite boxes.... I had to replace some capacitors to restore normal operation on a fairly expensive graphics card and friend had problems his american style fridge/freezer; again, capacitor related
Philips Senseo coffee machine for me :) I'm pretty awful with a soldering iron but managed to replace the failed part without too much trouble
 

4wd

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Just to add to the capacitor dept., have changed them in sat receiver, audio amps, pc power supply. Matching the capacitance value, and going up on the volt value. The higher the rated volt the longer it will last, only consideration is physical space available.
 

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Perhaps they should be renamed as Crapacitors ? :D
 

Analoguesat

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Some basic background info here:

http://en.wikipedia.org/wiki/Capacitor_plague


One story I heard is that industrial espionage was to blame. A worker in a factory was tempted away to a competitor and took the new electrolyte recipe with him. Unfortunately it wasnt quite finished......

The electrolyte boils when the cap gets hot which causes the bulges and the leaks.
 

Analoguesat

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Ive had no end of power supplies fail at work over the last 10 years. Computer internal & monitor external. At one point the monitor psu's were going down faster than I could get them exchanged by our supplier.

Some of the staff were less than impressed when their nice shiny new flatscreen monitors were temporarily replaced with 17" crt monstrosities I had in store :D
 
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