Re: [linux-dvb] Please see if you can help: Twinhan VP 1025 DVB-SPCICard
Dave Schile wrote: Well, I tried different compiles and saw nothing different. I found that this LNB uses an oscillator running at 11.25 GHz. So I put these lines in the dvb_defaults.h file for dvbtune: /* DVB-S */ // With a diseqc system you may need different values per LNB. I hope // no-one ever asks for that :-) #define SLOF (11700*1000UL) #define LOF1 (11250*1000UL) #define LOF2 (11250*1000UL) is that right? Still, the unit seems not to tune at all. I keep thinking I'm missing something simple. Also, the Opperation not supported messages have me dumbfounded while trying to 'dvbtune -m' The operation not supported message is fine. You can ignore it safely. Some people in North America with Circular polarizations have got back with problems with scan. Is it the same issue, other than the LNB LOF settings ? Manu ___ linux-dvb mailing list linux-dvb@linuxtv.org http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
Re: [linux-dvb] Please see if you can help: Twinhan VP 1025 DVB-SPCICard
I don't fully understand the real electrical/RF implications of circular left/right vs linear horizontal/vertical other than to say that it's related to how the signal is sent (polarised) from the satellite (it's polarisation) and that you have to have a matching LNB of the same polarisation. In some cases I've been able to receive circular right with a H/V LNB but that was a rare exception, circular left never worked. I'd say buy a linear H/V LNB if your goals are to tune to H/V feeds. I'm not suggesting this is your only issue but it's certainly one of the most important. If you have access to a spectrum analyzer when you could see very quickly the L-band representation to see whether the LNB is down-converting correctly, or whether you have a tuner related issue. Steve Thanks, Steve. I was getting confused because it appears that even if you specify R or L in channels.conf file, the response from szap still only shows V or H. Other documentation that I found says that circular right is activated on the LNB with 13 volts, the same as linear vertical would be activated. Circular left is activated with 18 volts the same way linear horizontal would be. Does that sound correct? Yes. dvbtune (via the standard linux API) really uses V/H to set 13/18. R and L basically mean the same thing (13/18). The electronics on the LNB however (triggered by 13/18) deal with the polarisations differently. If you trying to receive a V/H signal on a R/L LNB this is going to be a problem. You need to match a R/L LNB with a R/L polarised satellite feed. It's an easy test, re-align your dish to 119deg where you have regular DVB feeds running on R/L polarisations - matching your DSS circular LNB. (I did a whole bunch of tests with a spectrum anaylzer and rotating circular lnbs, no effect what-so-ever on the downconverted carrier. V/H on the other hand, well, it started to bleed energy from the opposite polarisation). In the end we bought a quad LNB for the lab in New York, able to put out Linear and Circular polarisations on a pair of cables. The LNB specifically handles polarisations for V/H, R/L. I am now starting to think that possibly the signal I'm trying to tune to is too weak. I am only using a small 18 inch DirecTV dish. Any insights on this? I used a 18 inch dish for DVB-S work at ome on 119 degress, I'd suggest you give it a try. Regards, Steve ___ linux-dvb mailing list linux-dvb@linuxtv.org http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
Re: [linux-dvb] Please see if you can help: Twinhan VP 1025 DVB-SPCICard
Unfortunately I dont know much about the LNB. I went and remove it from the dish but the identification sticker has worn away. It came from a common 18 inch DirecTV dish. there are two LNB's in there, I think, because there are two coax outs. I'm only using one at the moment because I dont have a disecq. Do you thnk this LNB w]ll cause my defines in dvbtune.c to need changing? Best, Dave Schile Yes, try setting the high and low defines to the same value in three different compile tests. 10.6, 10.75, 11.25. Leave the LNB switch setting alone. Steve ___ linux-dvb mailing list linux-dvb@linuxtv.org http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
Re: [linux-dvb] Please see if you can help: Twinhan VP 1025 DVB-SPCICard
Well, I tried different compiles and saw nothing different. I found that this LNB uses an oscillator running at 11.25 GHz. So I put these lines in the dvb_defaults.h file for dvbtune: /* DVB-S */ // With a diseqc system you may need different values per LNB. I hope // no-one ever asks for that :-) #define SLOF (11700*1000UL) #define LOF1 (11250*1000UL) #define LOF2 (11250*1000UL) is that right? Still, the unit seems not to tune at all. I keep thinking I'm missing something simple. Also, the Opperation not supported messages have me dumbfounded while trying to 'dvbtune -m' Let me ask you this: Once you know the correct oscillator value (11.25) do you adjust the freq. from lyngsat to get the number you give to dvbtune? I've just been using the freq. number in the first column on the lyngsat table. Thanks, Dave Schile Unfortunately I dont know much about the LNB. I went and remove it from the dish but the identification sticker has worn away. It came from a common 18 inch DirecTV dish. there are two LNB's in there, I think, because there are two coax outs. I'm only using one at the moment because I dont have a disecq. Do you thnk this LNB w]ll cause my defines in dvbtune.c to need changing? Best, Dave Schile Yes, try setting the high and low defines to the same value in three different compile tests. 10.6, 10.75, 11.25. Leave the LNB switch setting alone. Steve ___ linux-dvb mailing list linux-dvb@linuxtv.org http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
Re: [linux-dvb] Please see if you can help: Twinhan VP 1025 DVB-SPCICard
// With a diseqc system you may need different values per LNB. I hope // no-one ever asks for that :-) #define SLOF (11700*1000UL) #define LOF1 (11250*1000UL) #define LOF2 (11250*1000UL) is that right? Yes. Still, the unit seems not to tune at all. I keep thinking I'm missing something simple. Also, the Opperation not supported messages have me dumbfounded while trying to 'dvbtune -m' Let me ask you this: Once you know the correct oscillator value (11.25) do you adjust the freq. from lyngsat to get the number you give to dvbtune? I've just been using the freq. number in the first column on the lyngsat table. No. I've always used the actual Ku band frequency in dvbtune, not the l-band frequency. I don't have one of those cards so I can't really help. I know the above fixes always work for me for regular DVB H/V polarisations (when using a V/H polarised LNB). Doesn't DirectTV use L/R polarisation - and hence L/R LNBs? You are using an LNB supporting V/H polarisations, right? Steve ___ linux-dvb mailing list linux-dvb@linuxtv.org http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
