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79 posts

Master Geek


Topic # 15492 25-Aug-2007 19:36
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Any one got any Idea what the signal level is on the RF output on a Sky/Freeview Decoder???.

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  Reply # 83812 25-Aug-2007 22:38
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No, but it will be the same as on a VCR for which it would be much easier to find the info. It is in the order of mW, not much at all. Search for UHF modulator, there are a number of manufacturers of the modulator modules which will have datasheets with specifications.  Or find a VCR manual, it should be on the last few pages.




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Master Geek


  Reply # 83819 25-Aug-2007 23:56
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Cheers I would of thought it would have been in the range of dbmv as this is the measure of Frequency and some modulators can also give out an amplified signal but I wouldnt expect that from a STB or VCR as the signal does not have to travel far usually. Im just a we bit curious as I dont have the testing equipment yet to check this out myself.

 
 
 
 


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Ultimate Geek
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  Reply # 83861 26-Aug-2007 16:03
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Not sure if this helps, but I have a Jaycar modulator outputting a DVD player, RF feed goes into RF In on SKY STB and modulated RF Out is driving a Hills Distribution amplifier. Perfect reception of DVD and Sky around the house.

The Jaycar modulator has specs for RF Out of 70+or- 5dbuV, so I guess Sky STB RF Out will be similar given the Jaycar modulator is feeding Sky STB RF In with no problems.

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  Reply # 83868 26-Aug-2007 16:48
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Oh, I was asleep again.  Yes, the RF output strength is measured in dBuV (decibel relative to 1 microvolt).  Hills have a 4 channel modulator that outputs 75 dBuV into 75 Ohm.  I have found a datasheet for a Sony modulator which does 81 dBuV, so it is in that ballpark.




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  Reply # 83881 26-Aug-2007 17:58
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When I was trying to get things working here and had a signal meter, it was about 65dBµV when on ch 63, more on lower channels. Ended up having to attenuate the UHF antenna by 16dB, mix in all the modulated sources and then put that into the amplifier. That way the modulated channels are slightly stronger then the off air ones. too much more into the dist amp and it was co channeling splattering all over the place. Not ideal but its enough to get the CCD cameras and when I had it the skybox on all the TVs in relative clarity.




Richard rich.ms

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