What exactly is Mapping?

[ondarocks]

Ok I searched all over the forum and see Channel Mapping all the time, but never really saw an explanation of what it was. Can anyone give me a brief description? TIA

 

[DarrellP]

All OTA tuners have to "map" to the local channels. Most boxes give you a scan feature to search the airwaves for what channels are available in your area, just like when you hook your TV up to cable and tell it to scan for channels. When your receiver finds them, it "maps" it into it's guide.

If you have a local Analog channel 6 and it is CBS, when you scan, you'll get something like 6-1, 6-2 for the 2 available digital channels that CBS is broadcasting. The actual frequency may be UHF channel 44, but there is a thing called PSIP which is broadcast as part of the digital signal and it tells your stb how to decode the signal and the mapping is part of it.

 

[ondarocks]

I understad now. So what do u do if when it's mapping the channels and it picks up a channel that is snowey or doesn't come in clear. Does the installer have to go back up on the ladder 40ft until I get as many channels as possible or doesn he set the OTA says towards the Empire State Building ( for me at least ) and that's it. Back in the day I would just delete that channel.

 

[DarrellP]

Digital is all or nothing, no snow. With a borderline signal you will get dropouts or mass pixelation, picture freezing, etc, but no snow. You will always have a clean picture. Once the scanning feature is enabled, you should be able to delete channels you don't want in the guide. I currently have 2 channels mapped that I can't get and don't want. You will want your installer to position the antenna toward the antennas for your area to maximize the number of channels you will be able to receive.

 

[ondarocks]

ok, I understand Digital is all or nothing, but what about the analog channels? Maybe I'm not understanding a 100%....................Ok if I get the major local networks coming in on my Tv does that mean I picked it up digitally or is it in analog? For instance I know that if a TV show or sitcom comes on it might not be in in Hd, but say if CSI Miami is coming on after my analog show will I get that channel in HD or not? Wow now I just confused myself..............Are there two channels for 2,4,5,7 etc...... Is that what the 2.1 and 4.1 etc... means? Sorry for being a little uneducated right now.

 

[wasch_24]

ok, I understand Digital is all or nothing, but what about the analog channels? Maybe I'm not understanding a 100%....................Ok if I get the major local networks coming in on my Tv does that mean I picked it up digitally or is it in analog? For instance I know that if a TV show or sitcom comes on it might not be in in Hd, but say if CSI Miami is coming on after my analog show will I get that channel in HD or not? Wow now I just confused myself..............Are there two channels for 2,4,5,7 etc...... Is that what the 2.1 and 4.1 etc... means? Sorry for being a little uneducated right now.

Exactly, There can be several feeds coming from the same channel. If you are watching anything through the Voom STB then it is digital, regardless of whether or not it is HD. Now if your local broadcaster has decided not to broadcast anything then the PG will show "intermission".

 

[DarrellP]

A lot of stations broadcast HD on the .1 subchannel and SD on the .2, .3, etc. Our local CBS during March Madness actually had 3 different games going at the same time on the digital channels and one on the analog channel.