Blind Scan scans much slower on AMC6?

[Mr Tony]

For those with blind/smart scan recivers

Does anybody know why some satellites take FOREVER to scan and some can scan in no time flat?

Example
I can scan SBS6 and AMC9 in about 3-4 minutes. The exception is when the satellite has alot of stuff on it (during CBB or CFB season)

but AMC6, which has 2 active transponders on it 24/7 (one H one V) can take up to 10 minutes or more to scan it....and come back with only those 2.

Anybody have a reason? I know the more TP's on it, the longer it will take (for obvious reasons), but AMC6 seems to be a bugger.

And on this, is there anything on it ever? I've seen one BB game on it in the last 2 months.

 

[Diamond Jim]

I know what you mean. When I figured out how to scan each polarity separate with the 3618 scan times dropped to about 5 to 7 minutes per polarity, which isn't bad. With this 3688 format I have not figured out how to do that and it takes forever to scan. I agree, the more signals on a satellite, the faster it scans.

 

[mkm4]

.

Anybody have a reason? I know the more TP's on it, the longer it will take (for obvious reasons), but AMC6 seems to be a bugger.

.

Hmmm, maybe interference from the nearby DirectTV 5 satellite?

 

[Mr Tony]

but AMC4 at 101 (same spot as Direct) scans normally

and since 72.5 is a DBS slot, it wouldn't interfere with it because of the settings of the receiver.

But maybe Voom is adding stuff there and that is screwing up the scan time.

 

[Diamond Jim]

Tony,

AMC 6 is a long time scan for me also.

 

[Mr Tony]

I think it has something to do with Voom maybe moving there.....

Other than one WCBB game about a month ago, nothing is on there.

 

[mkm4]

I think it has something to do with Voom maybe moving there.....

Other than one WCBB game about a month ago, nothing is on there.

Oh yeah, I forgot about voOm. I know that many of their transponders on AMC-6 have been active in testing, for a few months now.

 

[Othea]

My guess is that the fewer transponders active, the longer it takes. My reasoning: The blind search function must search each transponder using all SR frequencies. On those satellites that have active transponders, the search goes on to the next transponder once it identifies the SR frequency used. For every inactive transponder, however, the blind search must continue through the entire range of SR frequencies. This would make the blind search longer on satellites having many inactive transponders, and much shorter on satellites with low SR frequencies.

 

[Diamond Jim]

Sounds good to me.

 

[Mr Tony]

not necessarily

I can scan AMC9, which sometimes can have maybe 2 TP's active (11775 H 4232 being one), but it scans MUCH faster than AMC6

 

[TuxCoder]

And remember, SR and frequency are two different things. I believe a blind search just slowly "moves the dial" digitally from a starting intermediate frequency (IF) and steps incrementally by some constant difference up to a final IF. After each increase it checks for a digitally modulated signal on that frequency. If one is found, it examines the signal to determine the FEC rate, then watches for DVB-S "symbols" on that signal and runs a brief timer to determine the symbol rate. Some receivers may pick the frequencies differently (stop at first one with signal, or move up and down a bit to find the best signal, perhaps where the FEC is least utilized).

 

[mkm4]

My guess is that the fewer transponders active, the longer it takes.

But, inactive transponders will have a lower signal strength than the activce ones. So it should skip them, seeing that there is no signal there.