Thanks, Dan. That helps a lot. Is there something about the DVB-S modulation that makes it astoundingly better for this application? For something that is intended to be widely received, they sure are making it difficult... Greg. KO6TH -- Sent from my new toy... Please ignore tupos.
Daniel Schultz <[email protected]> wrote: >------------- Original Message ------------- >>> Right. But what is that in terms of what normally gets described? >>> For example, I have a Digital TV card for my computer (Pinnacle PCTV > >>> HD). It says it does "ATSC digital TV (HDTV up to 1080i, and SDTV)" > >>> and "Clear QAM (unencrypted digital cable)". >>> >>> Am I even close? >>> >>> Greg KO6TH > >No, you are not even close. > >ATSC (Advanced Television Systems Committee) is the proprietary >over-the-air >television broadcast standard used in North America. It is >fundamentally >incompatible with the open source "DVB-T" broadcast standard that the >rest of >the world uses for domestic TV. (The fact that it was designed by a >committee >should tell you all that you need to know about that particular >political >sausage.) The "Cheap and Easy SDR" article in January QST requires >using a >DVB-T USB dongle which you need to purchase from a supplier that knows >that >you want to use it for SDR. The ATSC USB devices sold at Best Buy or >other >retail stores in the USA cannot be used for this purpose. > >QAM is used only by cable TV and is never broadcast over the air. (Most >cable >systems use encrypted QAM so you will still need to rent the decoder >box from >the cable company). > >DVB-S is the digital satellite TV standard that the "free to air" (FTA) >satellite receivers use. We are not talking about Direct TV or Dish TV, >but >the C band services. If you watch NASA TV or the foreign language TV >broadcasts directly from your C band dish, you are using DVB-S. This >standard >has been used for terrestrial ham ATV in some US cities. It would be >best to >contact the ATV experts directly to see what receivers they are using. >I don't >know which FTA receivers will work with the ISS ham TV. > >Bottom line is: ATSC and QAM decoders are not useful for receiving the >ISS ham >TV signals, and DVB-S is not widely used in the USA except by dedicated >"free >to air" hobbyists. If you bought your receiver card or dongle from any >US >consumer retail store, it almost certainly is not what you need for ISS >ham >TV. > >Dan Schultz N8FGV _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
