[mythtv-users] Dish gotchas?

Michael T. Dean mtdean at thirdcontact.com
Mon Apr 10 20:19:44 UTC 2006


On 04/10/2006 02:53 PM, Jesse Guardiani wrote:
> My take:
>
> My Dish 322

The dual-tuner DISH receivers are not good for Myth.  With them, only 
one of the tuners can use an IR remote (the other is RF only).  
Therefore, you end up only being able to tune one receiver from Myth.  
So, go with single tuner models like the 310/311.

> locks up frequently, shuts down at 3am for maintenance,  and misses IR blaster channel change commands frequently enough to be annoying.

I've never had an issue changing channels with my IR blaster (the 
"improved IR transmitter" at http://lirc.org/improved_transmitter.html ) 
other than when it tried to change the channel when the receiver wasn't 
listening (i.e. no satellite signal or no power on the sat box).  
Perhaps it was an issue with your transmitter or LIRC configuration.  
(Not that I blame you if that's the case.  It took a /lot/ of my time to 
figure out how to properly configure my transmitter/LIRC.)

>  For this reason and because I can't get HDTV from Dish for MythTV, I've gone the other direction and moved from Dish to cable. Things are much simpler using a real tuner device rather than an IR blaster.
>   

Which is not necessarily a bad idea.  Note that if the OP has signal 
quality problems, spending a few bucks on fixing them may improve the 
picture quality almost as much as going to a digital source.  See 
http://www.gossamer-threads.com/lists/ivtv/devel/17953#17953 for some 
ideas on how to improve signal quality.

> Program guide data was easy to get, but problematic because channels I didn't pay
> for would cause the 322 to lock and require a channel up or channel down command
> from the IR remote. So when my mother in law came over and tried to change the channel
> to a channel we didn't have it would screw up any future recordings until I came home and fixed it, OR she found the Dish remote and pressed channel up or down.
>   

Been there.  Done that.  I "fixed" it by adding a channel up command to 
my change_channel script just before the channel number is sent.  It 
slows down tuning, but the extra 0.4 seconds of the show isn't worth the 
risk.  :)

The only problem I still have is that a powered off receiver results in 
a multi-gigabyte recording of "Blackness and Silence."  I started to get 
into watching that (was very relaxing), but after a while, the show 
became too predictable.  ;)

Unfortunately, although I've found the Pronto discrete power codes for 
the DISH receivers ( 
http://www.remotecentral.com/cgi-bin/mboard/rc-discrete/thread.cgi?611 
), I haven't yet done the work of converting them to LIRC codes.  If 
someone did this, putting a discrete power on before the channel up 
before the channel number would make a "foolproof" channel change script 
(i.e. would fix problems cause by my foolishly putting my receiver in a 
bad state).

> I could remove those channels I didn't pay for from the datadirect lineup, but Dish adds and changes channels on almost a daily basis, so it's an uphill battle.
>   

0.20 will automatically remove new channels from your DataDirect lineup 
if desired.  Waiting for TMS to add that option to the lineup 
configuration doesn't seem like a good plan any longer.  Daniel already 
did 90+% of the work last week.  (Thanks, Daniel!)  I just have to get 
the remove-new-channels part coded up and I'll be posting a patch in Trac.

> Tuners become more expensive because you need a separate IR blaster

You can use the same IR blaster.  Technically, the difference between an 
IR transmitter and an IR blaster is that the transmitter may not have 
sufficient power to transmit a signal that can be received by multiple 
devices, but--by definition--an IR blaster does.  Often transmitters, 
such as the LIRC simple transmitter ( http://lirc.org/transmitters.html 
), need to be affixed to the receiver for proper reception.  Such a 
transmitter design would require multiple transmitters for multiple 
devices.  An IR blaster, however (like the improved transmitter I 
mentioned above), can send a signal to multiple devices (and, in my 
house, does).  By setting your DISH receivers to use separate remote 
codes, you can control many (as many as 16--one for each remote code 
supported by DISH) from the same IR blaster--if you're willing to pay 
$5x16 receivers.

> and RCA jack/card for each receiver.
>   

Which you'll also need for multiple capture devices using cable.  With 
the PVR-500, you can send a single RF-modulated feed into the device and 
it will use an internal splitter, but many 500's ship with the 
additional backplate providing additional connectors, anyway.  Also, 
it's almost always cheaper to buy 2 PVR-150's rather than 1 PVR-500, so 
you only need a 500 if you're lacking PCI slots.

> No firewire available, AFAIK.
>   

True for all DISH receivers.  Also, DISH receivers do not provide serial 
ports for channel changes, so you must use an IR transmitter.

Note that some DirecTV receivers provide serial ports for channel 
changes.  Also, there are DirecTV "mods" (i.e. from 169time) that do 
firewire output, but they're not really usable with Myth.  AIUI, the 
data is output in a 169time-proprietary format that can only be decoded 
with their Windows-based program.  The only case I've ever seen where 
someone had it working with Myth involved the mod'ed DirecTV receiver 
outputting to a Windows box, which was outputting to a Myth box (I don't 
even know if that person ever got automatic channel changing to work, 
though).  It seemed a complete waste of electricity to me.  ;)

So, the only real difference between DISH and DirecTV from a Myth 
standpoint is that DISH requires an IR transmitter.  However, I like 
using my one serial port for changing channels on all boxes.  Using 
DirecTV receivers with serial ports requires multiple serial ports on 
the Myth box (or hacking up a hardware or software solution that's far 
more complex than a LIRC transmitter/LIRC).

> I say stick with cable.
>   

I would only say the same if it's impossible to improve the quality of 
the cable signal (and, make sure you're not setting unrealistic 
expectations for the quality of the DISH signal--the limiting factor is 
NTSC, and a good analog NTSC signal is not much different from a good 
digital signal that's output as NTSC).  Check the post I linked above 
and make sure you've set appropriate recording profile parameters or 
send the signal direct to a TV (to ensure it's the signal that's the issue).

Mike



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