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Message: <blockquote data-quote="deeptho" data-source="post: 1109354" data-attributes="member: 215446">In case it is helpful to others:Last week I receive a cheap C-band LNB from China. The price was just below the threshold for paying importtax and VAT. As I want to use it on an offset dish (laminas 1200). I bought a seperate conical feedhorn + mounting bracket as well. [ATTACH=full]135457[/ATTACH]The mounting bracket did not fit, but after drilling a hole, I managed to fit it next to the KUband lnb. I would prefer the label to be on the bottom (rain shielding), but currently the bolt I used to attach the lnb is a bit long and prevents me from doing that.[ATTACH=full]135461[/ATTACH]In my first experiment, the LNB was actually in a different location (farther away from the centre). Not sure what it was pointing to, but the universal LNB was pointing to 53E and so the c-band signal must have come from somewhere between 45 and 53 E: I received a signal almost immediately, as confirmed by my blindscan software (carrier lock, good snr ...) but it had no useful DVB and I received nothing else. I also did not make much of an effort.On Saturday I decided to take it to the next level: I installed the LNB in its current position, and moved the dish until I got a signal on a satellite meter. Pretty quickly I received some signals from 40.0E but not many and  unfortunately, almost all were T2MI, so no picture yet.Another problems was that the LNB came without a dielectric plate. I could not immediately find any useful material to make one, so Iwent for an alternative solution, first proposed by doktorofsat (see elsewhere on this site). Specifically I used the modified design from  pride 21 as described here <a href="https://www.satellites.co.uk/forums/threads/dielectric-plate.115537/post-649938" target="_blank">Dielectric plate ?</a>However, I used some unconventional materials and so I am proud to announce the first fully biodegradable c-band depolariser: <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite6" alt=":cool:" title="Cool    :cool:" loading="lazy" data-shortname=":cool:" /> [ATTACH=full]135458[/ATTACH]Translation: this depolariser will destroy itself in the coming months.Basically, I printed "pride 21"'s pattern on a piece of paper, glued some aluminium foil on it  and then wrapped the paper around a piece of card board. After inserting in the LNB, the SNR on one of the polarisations went up by 3dB and the signal went away on the other one. I believe this is a pretty good result and so the design is a good one. I will pobably have it made on a PCB later. I used to have some FeCl and some left over cupper plate, but I cannot find it, so I will probably order it somewhere.With this setup, I could receive most of the T2Mi transponders on 40.E (but a few are missing), and even one regular DVB-S transponder, featuring RGVK Dagestan. SNR levels were pretty good. For example, here are a few results - note that the frequencies are wrong because my code thinks the LNB is for Ku-band.<ol> <li data-xf-list-type="ol"> freq=10908.108V Symrate=5119  Stream=0     pls_mode= 0:    0 SIG=-55.90dB SIG= 45% CNR=10.90dB CNR= 54% DVB-S2 8PSK FEC_3_4  INV_OFF PIL_OFF ROLL_25</li> <li data-xf-list-type="ol"> freq=10914.772V Symrate=5129  Stream=0     pls_mode= 0:    0 SIG=-53.71dB SIG= 47% CNR=11.00dB CNR= 55% DVB-S2 8PSK FEC_3_4  INV_OFF PIL_OFF ROLL_25</li> <li data-xf-list-type="ol"> freq=10921.441V Symrate=5119  Stream=0     pls_mode= 0:    0 SIG=-54.08dB SIG= 46% CNR=11.40dB CNR= 57% DVB-S2 8PSK FEC_3_4  INV_OFF PIL_OFF ROLL_25</li> <li data-xf-list-type="ol">freq=10928.116V Symrate=5129  Stream=0     pls_mode= 0:    0 SIG=-57.20dB SIG= 43% CNR=9.00dB CNR= 45% DVB-S2 8PSK FEC_3_4  INV_OFF PIL_OFF ROLL_25</li> <li data-xf-list-type="ol"> freq=10958.111V Symrate=5129  Stream=0     pls_mode= 0:    0 SIG=-53.98dB SIG= 47% CNR=11.80dB CNR= 59% DVB-S2 8PSK FEC_3_4  INV_OFF PIL_OFF ROLL_25</li> <li data-xf-list-type="ol">freq=10971.443V Symrate=5119  Stream=0     pls_mode= 0:    0 SIG=-56.20dB SIG= 44% CNR=10.80dB CNR= 54% DVB-S2 8PSK FEC_3_4  INV_OFF PIL_OFF ROLL_25</li> </ol>The following plot hows part of the spectrum (obtained with my blindscan software. Not sure why some transponders are missing, butI tried to receive them with a regular scan - no success either. I did not try very hard yet).[ATTACH=full]135459[/ATTACH]Still, I was a bit annoyed that this satellite is full of t2mi streams and I had not seen any of them. This was simply not acceptable. So just to get something, I tuned the transponder using a tuning program, recorded a transport stream using dvbsnoop and then used t2mi and vlc to view the result (note that the frequency in the example commandmay be for a different transponder than the screenshots):./neumo-tune -c tune -a 2 -f 10914000  -pH -U 1 -S 5120 -mPSK_8 --delsys DVBS2dvbsnoop -adapter 2 -s ts -tsraw -b   > /tmp/test.tscat /tmp/test.ts |./t2-mi 4096 1 > /tmp/x.tsThe result is 4 programs: one which is breaking up all the time (corrupt stream, maybe a bug in t2-mi?), but some others are working:[ATTACH=full]135460[/ATTACH]So what is next? Well obviously I need to scan the arc sometime. Also I need to modify my bindscan code to actually use a C-LNB. Right now, it still thinks my lnb is a ku-band lnb. In fact this modification is done, but I need to test it. Behind the scenes I have been working very hard to extend the blindscan code. By summer I hope to release it (but in my experience it always takes a lot more time than planned):<ul> <li data-xf-list-type="ul">save all scan results to a database</li> <li data-xf-list-type="ul">show epg as a list and a grid</li> <li data-xf-list-type="ul">allow to record programs in the epg</li> <li data-xf-list-type="ul">allow to live view these programs</li> <li data-xf-list-type="ul">control a positioner; detect which sat the dish is pointing you and "speak" the result</li> <li data-xf-list-type="ul">capture spectrum plots</li> <li data-xf-list-type="ul">deal with channel lists longer than 10 000 channels</li> <li data-xf-list-type="ul">deal with complicated LNB/dish  setups</li> <li data-xf-list-type="ul">decrypt streams using oscams (assuming you have a valid local viewing card; only local oscam supported)</li> </ul>Of course, tomorrow is April 1st, so it could all be an elaborate joke. On the other hand, today is March 31, and why would I ruin a joke  by announcing it? Perhaps I am not good at joking? Or perhaps it is fake news? Or perhaps not? Feel free to guess.</blockquote>

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