Different power levels, Linux & Windows

[ASegredo]

I have an OTA antenna in the attic. It feeds a preamp in the basement (no way to easily get power in the attic. The preamp has two splitter outputs, one goes to the first floor and one to the second. The first floor output goes into a four way splitter that feeds two televisions, a Windows computer and a Linux computer. The upstairs output goes to a two way splitter feeding a television and a Linux computer. All the computers have HVR-1600 or 1800 PCI cards.
The Windows computer has an old Athlon 64 cpu DDR 2 memory and IDE hard drives. Running windows 7, no updates.
The downstairs Linux computer is a Ryzen 2700X 32G DDR4 memory. The upstairs computer has a Phenom II X6 and 8G of DDR-3(?) memory.
The weak Windows computer shows 100% signal strength on almost all channels and plays nicely in the client. Both Linux computers used to work well but now have between 20% and 60% signal strength mostly around 50%. 60% will play with stuttering and freezing. 50% won't display a picture in preview.

????? The oldest computer is the best? Why? And what steps should I take?
SageTV9, latest versions on all the computers from Stuckless' JFrog binary repo.
Linux computers used to play all right but after the last channel shakeup and power reduction, they have gradually deteriorated. But the old weak box still records fine and all the TV's play fine without artifacts.

[jpwegas]

Originally Posted by ASegredo

I have an OTA antenna in the attic. It feeds a preamp in the basement (no way to easily get power in the attic.

Sorry, no ideas why you are seeing this difference, but I did want to mention that there are amps that can use power injected into the COAX so you don't have to run a separate 120V line near the antenna.

The "Assembly Instructions" for this amp show how it works (see attached):

https://store.antennasdirect.com/JUICE.html

--John

[ASegredo]

I do have a clearsteam antenna! Thanks for the link. It should help noise figure anyway.

My big puzzle here was the difference between Sage9 for windows and Sage9 for Linux on what should be the same input with substantially the same cards.
I bought a new HVR-1800 (PCIe) and I'll see if that makes any difference. Also, I'll try swapping taps on the splitter. (One Linux box is on the same splitter as the windows box)

[wnjj]

Maybe there’s a difference in the drivers between Linux and Windows. Are the Linux drivers up to date?

[wayner]

Ever consider HDHomeRun tuners? I think they make more sense as they are network devices and can easily be shared across multiple PCs running SageTV. If you ever could get power (and ethernet) in your attic you could also put the HDHR tuner in your attic and run an ethernet cable to your main network switch.

[ASegredo]

Originally Posted by wnjj

Are the Linux drivers up to date?

I think so. Sage 9.2.2.268, kernel 5.4.66

Windows Sage 9.2.1.826

[ASegredo]

Originally Posted by wayner

Ever consider HDHomeRun tuners?

Several years ago in the sage 7 days. It never did work and I wound up giving it away. When I say "Didn't work", I mean with windows. I didn't have sageTV for Linux until v9

[ASegredo]

I removed the splitter between upstairs and downstairs leaving upstairs disconnected. This should have doubled downstairs power but Linux signal strength was unchanged at 56% to 58% jut on the verge of stalling.
I replaced the PCT amplifier with a motorola. No change.

Next step, replacing the TV card. However, I suspect that it might be a problem with these latest kernels. I'll boot the oldest I have and see if it helps.

[ASegredo]

VERY interesting.
Video played fine with kernel 4.14.194
There is no sound but I switched to a Turtle Beach card last year and support isn't turned on in that kernel.
Kernel 4.17.9 has video stalls and of course no sound.

So, it doesn't seem to be a signal strength problem at all, but rather a driver problem.

[ASegredo]

Found this at https://www.mythtv.org/wiki/Hauppauge_HVR-1600

"Drivers included in recent kernels may contain a bug which causes stuttering in TV playback. "

besides the standalone Box and USB boxes, does anyone have a recommendation for a PCI-e card?

[wayner]

Did you try swapping cables between the Windows and Linux boxes to ensure that it isn't a bad cable?

[ASegredo]

Not yet but removing the two way splitter had no effect.

I found that mplayer is taking 30% of a 2700X. That's a lot of horsepower.

I also recorded a program and played it back with xine. it was perfect.

I will try the other hardware swaps but don't have much hope fpr them when the earlier kernel had no problem. I compared the drivers with "meld" but lthough there were many changes they seemed innocuos. Things like removing spaces that occur before a tab and changing " if <somevariable> != NULL" to " if !<somevariable>"

[jpwegas]

Originally Posted by ASegredo

Found this at https://www.mythtv.org/wiki/Hauppauge_HVR-1600

"Drivers included in recent kernels may contain a bug which causes stuttering in TV playback. "

besides the standalone Box and USB boxes, does anyone have a recommendation for a PCI-e card?

That page has not changed since 2011 so that statement is likely not referring to recent 4.x kernels.

--John

[ASegredo]

I replaced the PCI HVR-1600 with a PCie HVR-1800 last night and all artifacts are gone. may have been a bad card. However, I still have freezing video on live play with audio smooth as silk. mplayer playback of recorded video is perfect, both with the bundled mplayer and the system mplayer. I'm thinking it's caused by insufficient buffering. Strange that it would occur on the more powerful 2700X/32G RAM instead of on the Phenom II X6/8G RAM.

I see very old forum posts going back to sage 3 and sage 5 about this but not more recently.