[mythtv-users] DVB-S Users: Anyone have C-band?

[Robert Denier]

Bear in mind that my C-band info is not current.  We never purchased a
4DTV system because it just wasn't cost effective compared to the little
dishes especially with multiple receivers.  I think 4DTV receivers might
have a second channel number for digital channels, although I do not
know the details.

On Sun, 2005-10-30 at 15:50 -0700, Greg Grotsky wrote:
> I currently have a DVB-T setup with MythTV working using the HD-3000
> and I like it alot.  I've been thinking lately that it would be really
> cool to have a satellite hookup and access to many more than just the
> 6-7 local ATSC channels.  I checked out the zap2it config for
> satellite C-band and 4DTV channels, they are both loaded with
> stations.
> 
> I did some research about doing C-band (8' dish) and I'm wondering how
> does one control the actuators on the dish in order to point it at
> different satellites?  

Generally on the remotes you would have a letter key assigned to each
number key.  I.E. 0 - 9 were different letters.  Satcom 1 just became F1
and Galaxy 3 became G3 and so on.  On the remote you would press

Sat -> G -> 3  except the G was really one of the number keys..

This would change to a particular satellite and then you would change
the channel by either the up/down button or entering 1-24.

> All the acutator control information and tuned channel data doesn't
> come down the same coax cable, does it?

The C-band system we have uses a set of wires for the linear actuator, a
set of 3 wires for the polarization motor, and a coaxial cable for the
C-band signals.  Any newer units will have a second coaxial cable for Ku
band signals.  The actuator wires typically run at something like 24-36
volts with the direction of movement controlled by which one is made
positive.  A thin pair of wires return pulses to track position.

Breifly here are some of the advantages of C-band..

1) C-band has somewhat better picture, at least on some channels.  The
last I looked you still had many channels being sent over analog
scrambling which means, in general, using something like 6MHz to send
the picture.  An analog picture sent over that much bandwidth will
usually be better than a digital picture sent over a small dish,
although it really depends on how much bandwidth the small dish system
can dedicate to the channel..  One thing I noticed when I did a side by
side comparison some time ago was that very fine details were smudged a
bit by the small dish.

2) Want some of the channels that are only on C-band.  To be honest I
can't think of anything there that I care for anymore, but there are
wild feeds and such.  Of course most of it you can't find a listing for.
I do remember losing patience waiting for the next weeks episode of a
show and finding the feed of it television stations were meant to
record..  

3) C-band is, or at least last I looked anyway, was cheaper, but you get
fewer channels and you really can't use multiple receivers without
multiple dishes, and even then you negate any savings..

In general 3 doesn't apply to me because we have several receivers.  I
can't think of any channels on C-band I want anymore.  I thought about
just buying HBO (You can buy 1 channel and it probably would still be
cheaper than adding it to the small dish) there and connecting it to
myth, but that would likely be a pain.  Finally the picture difference
is not that big of a deal, and there is a lot more maintenance involved
in keeping C-band systems performing at their peak compared to small
dish systems...

-Robert