[amsat-bb] Re: ISS HamTV Frequencies
ko6th.greg at gmail.com
Mon May 13 07:18:38 PDT 2013
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...
Sent from my new toy... Please ignore tupos.
Daniel Schultz <n8fgv at usa.net> 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
>television broadcast standard used in North America. It is
>incompatible with the open source "DVB-T" broadcast standard that the
>the world uses for domestic TV. (The fact that it was designed by a
>should tell you all that you need to know about that particular
>sausage.) The "Cheap and Easy SDR" article in January QST requires
>DVB-T USB dongle which you need to purchase from a supplier that knows
>you want to use it for SDR. The ATSC USB devices sold at Best Buy or
>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
>systems use encrypted QAM so you will still need to rent the decoder
>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,
>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
>has been used for terrestrial ham ATV in some US cities. It would be
>contact the ATV experts directly to see what receivers they are using.
>know which FTA receivers will work with the ISS ham TV.
>Bottom line is: ATSC and QAM decoders are not useful for receiving the
>TV signals, and DVB-S is not widely used in the USA except by dedicated
>to air" hobbyists. If you bought your receiver card or dongle from any
>consumer retail store, it almost certainly is not what you need for ISS
>Dan Schultz N8FGV
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