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Can I use SCAN like the former DTVSIGNAL?
http://forums.linhes.org/viewtopic.php?f=5&t=16964		 Page 1 of 1
Author:  neutron68 [ Sun Oct 14, 2007 1:10 pm ]
Post subject:  Can I use SCAN like the former DTVSIGNAL?
I know that the "atscscan" and "dvbscan" utilities have been replaced with a single unified "scan" program.
I know that in order to use the "scan" program, you to stop the mythtv-backend. I use the ALT-2 keystroke in the Mythtv GUI.

I want to get a signal strength reading from an over-the-air HDTV channel (hardware and KM details in signature). This used to be done with the "dtvsignal" program. Can this be done with the "scan" command line program?
Or do I need to go to the pchdtv.com site and get DTVSIGNAL from the "dvb-atsc-tools" download?
Author:  tjc [ Sun Oct 14, 2007 2:09 pm ]
Post subject: 
Did you try:
Code:
scan --help

One of the vebose "-v" or output format "-o" options may give you what you want.
Author:  neutron68 [ Sun Oct 14, 2007 7:06 pm ]
Post subject:  concluded that "dtvsignal" is necessary
tjc wrote:
Did you try:
Code:
scan --help


I did try "scan --help". There are no switches that are anything related to signal strength.
I've concluded that those of us who want to get a signal strength reading need to download, compile and run "dtvsignal". I used:
Code:
cd /usr/src
wget http://pchdtv.com/downloads/dvb-atsc-tools-1.0.7.tgz
tar -zxvf dvb-atsc-tools-1.0.7.tgz
cd /usr/src/dvb-atsc-tools-1.0.7
make
make install

All you have to do is type "dtvsignal XX" where the XX is the over the air channel number you want. So, I'm back in business, as they say. :)

Thinking back, I can't remember if "dtvsignal" was in past Knoppmyth versions such as R5C7 and R5D1. Can anyone recall?

Cheers!
Author:  neutron68 [ Mon Feb 11, 2008 7:44 pm ]
Post subject:  getting error during make?!
After doing an R5F27 upgrade to Knoppmyth, I'm reloading all the apps I like to use.
I just tried to compile the dtvsignal program with the list of commands shown above. It worked fine in R5F1.
This time, I'm getting errors. Any clues why and how to fix it? Am I missing some needed files?
Code:
root@mythtv:/usr/src/dvb-atsc-tools-1.0.7# ls
Makefile  atscpackets.c   dtvscan.c    dtvsnr.c
README    chopatscfile.c  dtvsignal.c  getatsc.c
root@mythtv:/usr/src/dvb-atsc-tools-1.0.7# make
gcc -Wall -D_FILE_OFFSET_BITS=64     chopatscfile.c   -o chopatscfile
chopatscfile.c:41:28: error: linux/videodev.h: No such file or directory
make: *** [chopatscfile] Error 1

Advice needed,
Eric
Author:  jbm2131 [ Mon Feb 11, 2008 10:06 pm ]
Post subject: 
Could it be related to the missing dvb headers? See http://mysettopbox.tv/phpBB2/viewtopic.php?t=16434.
Author:  neutron68 [ Mon Feb 11, 2008 10:54 pm ]
Post subject:  thanks for the tip
Thanks for the tip. Is this downloading of DVB libraries necessary because it used to be part of Knoppmyth but has been removed? I never had to do this before.
Author:  jbm2131 [ Tue Feb 12, 2008 1:37 am ]
Post subject: 
I think it is just a R5F27 problem. A few of the header files were simlinked to non-existent files.
Author:  jzigmyth [ Tue Feb 12, 2008 9:49 am ]
Post subject: 
Maybe I'm missing something in the question, but all you have to do to get signal strength in R5F27 is watch live tv, tune in an atsc channel and then hit F7 on the keyboard, the picture disappears and the signal strength bounces around in an osd. Hit F7 again and the picture returns to normal.
Ziggy
Author:  neutron68 [ Tue Feb 12, 2008 10:04 am ]
Post subject:  DTVSIGNAL - a better view!
If you have not used DTVSIGNAL, then I would say, yes, you are missing something. :)

DTVSIGNAL gives you a real-time look at signal strength. You can see it bouncing around, it that is what it is doing. For example, a bouncing signal reading could mean multipath interference, etc. The OSD signal method you described only shows you a static snapshot of the signal strength at one point in time, which is not useful as a real time updating meter.
Author:  jzigmyth [ Tue Feb 12, 2008 10:18 am ]
Post subject:  Re: DTVSIGNAL - a better view!
neutron68 wrote:
The OSD signal method you described only shows you a static snapshot of the signal strength at one point in time, which is not useful as a real time updating meter.
It's not a static snapshot on my box. When I hit F7 the picture goes away, the OSD comes up, and the signal strength percentage bounces around all over the place and the word "lock" changes between "lock", "no_lock" and "partial_lock" as I move the antenna around. It certainly looks like a real time display. When I hit F7 again it goes away and the picture comes back.

Edit: This is with an HD-3000 tuner card maybe different cards respond differently.
Edit again: Oh, wait, I see from your sig that you have an HD-3000, too!?
Author:  neutron68 [ Wed Feb 13, 2008 9:20 am ]
Post subject:  Re: DTVSIGNAL - a better view!
jzigmyth wrote:
It's not a static snapshot on my box. When I hit F7 the picture goes away, the OSD comes up, and the signal strength percentage bounces around all over the place and the word "lock" changes between "lock", "no_lock" and "partial_lock" as I move the antenna around.

Hummm. What version of Knoppmyth are you running? I *just* upgraded my machine from R5F1 to R5F27 and have not noticed if the OSD signal strength update has changed it's behavior from R5F1 - which was a essentially static reading at the point of signal aquisition. I've not been aware of hitting F7 to view signal strength. I'll try it.

I read the forum post about downloading the v4l and DVB code and linking the headers to the Knoppmyth kernel. I got DTVSIGNAL compiled last night.
DTVSIGNAL is a command line program that stays onscreen as long as you care to run it updating several times a second, so it acts more like an analog signal meter. The output looks like this:

Image
Author:  neutron68 [ Thu Feb 14, 2008 9:02 am ]
Post subject:  F7 - neat!
Thanks for the tip on hitting F7 right after you change channels and get some On Screen Display data from the new channel.

I have never seen any info on hitting F7 to freeze the OSD and hold the signal readout. It's nice. :)

I still like having DTVSIGNAL available, but this F7 trick may become the new signal meter of choice - since you don't have to stop the mythtv backend and type on a command line.

Thanks!
Eric
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