[MLB-WIRELESS] Nasa Tv over MW

[Tony Langdon, VK3JED]

At 09:16 PM 9/19/2007, Peter Berrett wrote:

>First some background. I am an amateur radio/tv enthusiast and also I
>have a few dishes that sometimes are used to receive satellite tv. NASA
>Television is available via the Intelsat 701 satellite and there are no
>copyright problems with retransmitting it. I have wanted for some time
>to transmit this through the vk3rtv repeater however in Australia the
>Amateur Radio rules are a bit more restrictive than in the USA where it
>is common.

Hmm, I haven't looked into it on the TV side.  Does it qualify as a 
"broadcast of interest to radio amateurs"?  - this is an amendment 
that came into the regs in 2000 after a little controversy.  This is 
also the same time when the WIA's exemption on offering goods for 
sale on behalf of their members was revoked.  I remember these 
changes well, because I was involved near the centre of the 
controversy at the time.


>However the fast speeds of Melbourne Wireless seem suited to a service
>streaming Nasa TV. I wonder how viable/practical this would be to setup?
>Assuming I could get a PAL feed from Intelsat 701 what equipment and
>software would I need to make this streaming tv service available across
>the network.

PAL or NTSC, doesn't matter as long as you can process it.  Well for 
high quality transmission, you need a reliable 300kbps per user.  I 
can't see that scaling, unless multicast is enabled across the MW 
network (which is extremely unlikely).


>More importantly however what would happen if say 100 people all wanted
>to watch NASA TV at the same time on the network eg due to a shuttle
>launch? Would the streaming tv have to be carried 100 separate times
>across the network thus overloading the system or is there some way to
>distribute one signal across the network and people can just passively
>receive the streamed packets?

You would need multicast, which means that all routers in the network 
need to support IGMP and one or more multicast routing 
protocols.  Otherwise it's one stream per user, which will kill the network.

73 de VK3JED
http://vkradio.com