[mythtv-users] PVR-150 Tuner Quality Issues

[Brian Wood]

On Apr 15, 2006, at 11:49 PM, Michael Horn wrote:

> On Apr 15, 2006, at 10:32 PM, Michael Horn wrote:
>
> > Ok, I've finally got my mythtv box set up and running. I'm still in
> > the process of tweaking it and my current issue involves the
> > picture quality of the tuner in the pvr-150. While the picture is
> > certainly watchable, colors are very dull, and the image is very
> > grainy. I've played with different capture resolutions, and have
> > ruled that out as an issue. My next step was to try out the tuner
> > in my good old vcr. I ran the cable line to the vcr, and then
> > composite cables to the pvr-150, and got a huge increase in picture
> > quality, colors looked better, smoother image etc. Now, I'm hoping
> > this is an issue that can be resolved, be it through software
> > settings or whatever, as I'd hate to thing the tuner in my cheap
> > vcr does such a better job than that in the pvr-150, especially
> > after all the reviews ive read of the great picture quality. Any
> > suggestions to improve the tuner quality would be greatly
> > appreciated, or else it looks like I'll be settin up the ir blaster
> > to take advantage of my vcr tuner.
> >
>
> Have you tried adjusting the fine-tuning, or is it possible that you
> are using the incorrect frequency table (STD,IRC or HRC) and your
> tuner is just barely pulling it in? What you describe could be caused
> by being off freq. a bit.
>
> I have also compared the RF-tuned signal to using the baseband inputs
> from an external tuner and found them to be virtually identical, and
> that's on 4 different PVR-150s.
>
> I do know, however, that HogPaws has used several different tuner
> modules, and perhaps some are better than others, but I have two
> different modules (my MCE version is different) and they all look the
> same.
>
> Thanks for the the quick response Brian. The frequency table I'm  
> using is correct. As for fine tuning, I'll check that out and see  
> if it helps. I don't know if this will help to diagnose the  
> problem, but on top of the general graininess and poor color, the  
> lower channels seem to exhibit kinda of a rolling interference as  
> well.
> Also, the tuner in my unit was never automatically detected, so  
> I've had to pass the tuner type to the module, and have been using  
> 50 from the beginning as it was the first I tried and allowed me to  
> pull an image. I'll go ahead and start playing around with some  
> others, but could that have a bearing on this as well? And finally,  
> on that note, is there any resource out there that combines some  
> documentation on all the different options that can be passed to  
> the ivtv module in one place? in my searches involving different  
> issues I've managed to piece together what some of them do, but  
> some sort of inclusive documentation would be great.

Quick response was because I just happened to be online, ranting  
about RedHat/Fedora :-)

The lower channels having the problems you describe points to a loose/ 
bad cable/connector going to the card. Have you tried your VCR/tuner  
using the exact same connector as is feeding the card?

It seems odd that your tuner isn't detected properly. 3 of my 150s  
are correctly detected as type 50, the fourth (a 150MCE) is a type  
4.  Are you using an up-to-date IVTV ?? I'd think that if the  
channels tune OK then you have the correct type, OTOH you may not be  
tuning them correctly, certainly something is wrong as a lot of 150s  
are in use and if your situation was common I think we'd know about it.

As for IVTV docs, I'd think the definitive place would be the ivtv  
site itself. I've never had any reason to pass commands directly to ivtv