Question about how blind scan works

[Alan Rovner]

Hi guys, I regularly read Rick's wildfeed site to see what's new and the guys there post feeds in great detail, including FEC (I know what that is) and Pilot (I don't know what that is). A couple questions:

Why do I need to know FEC and Pilot? This isn't something I can change or adjust at least on my receiver.

When I do a blind scan does it search only the TPs in the receiver's database, or perform a complete tune covering the complete range of the LNBF? Maybe it can do both, I'm not sure. If I see a TP listed on Rick's site that isn't included in my database do I need to add it by hand using an editor? Sounds like a lot of work.

Thanks,
Al Rovner, K7AR

 

[KE4EST]

FEC is good to know, for reference.

When a receiver does a blind scan it scans the frequency range looking for a signal. When it locates one it stops and checks to see if there is anything on there it can tune. If so it will scan for channels.
A transponder scan is just that--it scans the transponder list in your receiver. So no, you do not need to go through and add every frequency you see posted by anyone else.

Frame synchronization is needed to indicate the start of each FEC block for the decoder. It also provides the necessary information for the receiver to apply the appropriate demodulator and decoder to demodulate and decode the transmitted information. Given that some overhead is necessary for frame synchronization, it is also designed such that it can be used to reduce initial frequency and phase uncertainty of the modulated signal. The frame synchronization is designed to provide reliable operation in the worst case Signal to Noise ratio with minimum overhead. It is also used to minimize the demodulator implementation loss in the presence of consumer quality low-noise-block (LNB) phase noise. In fact, phase noise is particularly detrimental to demodulator performance for higher-order modulation such as 8PSK, 16APSK, and 32APSK. To preserve the near Shannon limit performance of the DVB-S2 FEC, pilot symbols may be added to assist the demodulator to minimize probability of cycle-slips and to provide more accurate phase estimates. These pilot symbols are also designed to use a minimum overhead of the overall bandwidth, and can be turned on or off as desired.

 

[Lone Gunman]

Why do I need to know FEC and Pilot?

FEC and Pilot are/can be important for those of us who have older receivers, like the AZBox Elite, which has NO blind scan capability. PIDs can be important for those receivers as well as sometimes you have to enter ALL that info to get a TP to lock.