Scan/TP Question

[Spine]

Hello All,

I beleive the blind scan of many FTA receivers will scan a specified frequency range and look for all channels (or transponders) in that range, effectively finding all transponders and channels in that range. My receiver also has an auto scan which only scans the transponders in it's list.

Since it takes quite a while longer to do a blind scan than auto scan, I was wondering if it is required to do a blind scan, and if so what satellites?

My theory (please correct me if i am wrong), is that a satellite is built with a specified number of transponders and launched. I know they can turn them on and off, but can they change the frequency of the transponders once it is in space? If not, is doing a blind scan all the time a waste of time?

I guess some sats have a "steerable" beam which could make TPS available to different geographic areas on command, but if we know in advance of all the TPS on the sat, and always scan all the TPs, even the steerable, we should not miss any new feeds popping up?

I'm just curious what everyone else's philosophy is.

Thanks

 

[Tron]

Blind scan is necessary with digital satellite signals if you want to find new or unpublished (or temporary, as in the case of news feeds) signals. Symbol rates and PIDs can (and do) change regularly, plus many transponders are not included in the receivers list.

 

[Spine]

If I make sure I have all the transponders entered in my receivers list, and just do "auto scan" (scan the list of TPs), will it detect new SR and PIDS for that TP, or just PIDS?

Thanks for replying,
Mike

 

[brentb636]

If I make sure I have all the transponders entered in my receivers list, and just do "auto scan" (scan the list of TPs), will it detect new SR and PIDS for that TP, or just PIDS?

Thanks for replying,
Mike

I don't think so . When you define a transponder entry, you also create a SR for it. The STB is not going to "analyze" each transponder for different Symbol Rate values in "autoscan".

This issue is largely the reason I added a FortecStar Classic NA to my system. My first STB didn't have "blindscan" capabilities , and my only recourse was to define a large number of transponders on each bird that I wanted to scan. Then I ran into the SR problem, and realized I didn't have time ( or STB memory) to define all the possible combinations. I needed a discovery agent, and "Blindscan" is that agent.

 

[sikma]

On my Pansat 2700R, I have compiled about 60 tp's on SBS6 and IA6, so a lot of the times I just scroll through the tp list using my 'advanced scan' feature in the menu and look for a live tp. Then I scan that tp and it will detect new pid's and pcr's.