[linux-dvb] problems using a rotor [possibly related to lost lock thread]

Jeremy Hall 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 
version 1.3.23.

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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