roll-off setting in scanning

never used anything other than auto m8 and as for what it does im clueless im afraid
 
gibertini said:
never used anything other than auto m8 and as for what it does im clueless im afraid
Click to expand...
Thank you gibertini, after reading this I will stick to auto as I am still none the wiser :-lol.
http://en.wikipedia.org/wiki/Roll-off

Roll-off is a term commonly used to describe the steepness of a transmission function with frequency, particularly in electrical network analysis, and most especially in connection with filter circuits in the transition between a passband and a stopband. It is most typically applied to the insertion loss of the network, but can in principle be applied to any relevant function of frequency, and any technology, not just electronics. It is usual to measure roll-off as a function of logarithmic frequency, consequently, the units of roll-off are either decibels per decade (dB/decade), where a decade is a 10-times increase in frequency, or decibels per octave (dB/8ve), where an octave is 2-times increase in frequency.
The concept of roll-off stems from the fact that in many networks roll-off tends towards a constant gradient at frequencies well away from the cut-off point of the frequency curve. Roll-off enables the cut-off performance of such a filter network to be reduced to a single number. Note that roll-off can occur with decreasing frequency as well as increasing frequency, depending on the bandform of the filter being considered: for instance a low-pass filter will roll-off with increasing frequency, but a high-pass filter or the lower stopband of a band-pass filter will roll-off with decreasing frequency. For brevity, this article describes only low-pass filters. This is to be taken in the spirit of prototype filters; the same principles may be applied to high-pass filters by interchanging phrases such as "above cut-off frequency" and "below cut-off frequency".
 
I certainly will sleep easier knowing that Martin.....:-lol
 
You do ask some hard ones martin.:)
Well as far as I am concerned.:)
 
Blinded me with science as the great Magnus Pike said.
 
i thought inversion was what they used back in the analogue days for C-band transmissions...
 
In your screenshot, there's an inversion option. I guess it doesn't apply to digital satellite?
 
I have no idea CJ, after a google that's about all I could find, maybe I should have a deeper look and confuse myself even more lol, one thing this box does that my others don't is scans in data channels,

Obviously I cant view anything from them (yet) but it does lock them in maybe something to do with that ?,
 
AFAIK there is no real advantage to spectrum inversion ..it is simply a product of lnb design ..
Local osc signal when mixed with incoming signal resulting output being either correct way up or inverted ...
Most likley as a result of the LO being higher than the signal frequency ..or lower ..
The difference fequency passed to the receiver is either acceptable to the tuner or indeed inverted as a result..
Thus correction to invert or not invert being neccessary.
Please correct me if I got this wrong ...
rgds
VS..

Roll off AFAIK is an operation performed after a night of passion spent with a loved one ..
:)
 
Vipersan said:
Roll off AFAIK is an operation performed after a night of passion spent with a loved one ..
:)
Click to expand...

:-rofl2:-rofl2:-rofl2 Always based upon the assumption you rolled on in the first place
 
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