[linux-dvb] problems using a rotor [possibly related to lost lock
jhall at maoz.com
Sun Sep 25 20:39:10 CEST 2005
I have a nexus rev2.3 and have it connected to a diseqc switch and then to
a v-box which is connected to a rotor via 4-wire, and has a passthru to an
LNB so you can get signal down.
The rotor is operating normally, and I am using a modified version of the
rotor plugin which Thomas helped me craft to show actual DB values for SNR
and signal strength on the OSD using the skincurses plugin with vdr
At first, I was having problems with the rotor because I had just replaced
my standard US-based LNB with a universal one. When I moved the rotor
around using the step commands, if I was trying to watch a transponder
that required 22khz tone to be on, i.e. the LOF was 10600 instead of 9750,
I would immediately lose lock because when the rotor plugin sent the step
command somehow tone would get turned off.
I put in a hack to cause the plugin to wait 250ms then activate or
deactivate tone based on SLOF, which is set to 11,700.
Now I can move the rotor around but sometimes I will send the step command
and nothing special happens, meaning the rotor won't move. If I press
halt, then press ok while on the frequency line, the transponder is tuned
again and the rotor will once again move.
In this process, sometimes the card gets in a strange state--i.e. it shows
a signal strength of -infinity and a snr of 3.7db or less. Sometimes
restarting vdr fixes this, sometimes it requires reloading the modules.
Sometimes the signal strength shows marginal lock even though it "should"
show a very high strength of 18db or greater. For Example, the SNR might
show 6.0DB, I restart the drivers, restart vdr, the rotor doesn't move,
and suddenly the signal strength is up to like 15db or so.
It's frustrating, because if I'm trying to point the rotor, I don't know
if my lack of signal is genuine or not. There are too many variables to
set them, then restart all the drivers and vdr just to move one or two
In the current setup, if the rotor is pointed correctly, due to a stored
position is accurate, then after sitting at that location, the card will
finally lock to the transponder after about 10 or more seconds.
If the position isn't quite accurate, nudging the rotor in some direction
may occasionally show a blip, but rarely shows predictable values.
I'm in the mood to get a budget card anyways. Is there a budget card that
doesn't have these problems, or is the current CVS just broken in this
regard for all cards?
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