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Kje kupiti 3m krožnik? Ogled Astra 2D https://telstar.si/viewtopic.php?f=13&t=10137 |
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Avtor: | Tehnicni [ Pe Nov 11, 2011 20:17 ] |
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Glede širine snopa naj ne bi bilo razlike med ofsetko in klasiko. Teorija anten govori, da je med ojačanjem in širino snopa neposredna korelacija, torej kot je odvisen od ojačanje, ojačanje pa od velikosti zrcala - seveda če gre za enako kakovost zrcala in ostalih parametrov. |
Avtor: | yunnowho [ Pe Nov 11, 2011 20:38 ] |
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V bistvu kako širok je sprejemni snop zavisi od F/d razmerja, t.j. globina zrcala definira širino snopa. Kot npr. št. direktorjev na yagi anteni. Pri offsetni je ponavadi F/d = 0.6... 0.8, pri parabolični je pa večinoma F/d = 0.30...0.36 F/d zavisi od konstrukcije zrcala -> http://www.satlex.de/sl/fdratio.html |
Avtor: | Tehnicni [ Pe Nov 11, 2011 21:51 ] |
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To ne more biti res, širina snopa je odvisna od premera antene. To ti pove logika, pri obeh tipih anten gre za fazne razlike poti signala na levem in desnem oziroma zgornjem in spodnjem robu, le ta pa ni odvisna od F/d, ampak samo od d. |
Avtor: | SatFaca [ Pe Nov 11, 2011 22:25 ] |
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Antene z razmerjem .25-.32 so tretirane kot globoke in tiste med .33-.42 kot plitve. Globoke imajo nekoliko manjše ojačanje vendar dosti bolje zavračajo neželjene signale (šum, interference). Pri globokih antenah je goriščna razdalja (fokus) manjša - feed je bližje anteni, pri plitvih pa je feed bolj oddaljen. Velja tudi da globja in večja kot je antena, bolj ozek je glavni sprejemni signal in težje je natančno nastaviti anteno. |
Avtor: | Tehnicni [ So Nov 12, 2011 21:03 ] |
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Verjamem, da so razlike, predvsem v bočnih snopih, ki jih je pri globoki anteni manj, ampak glavni snop naj bi bil pa pri vseh antenah enake oblike, širina je pa odvisna od premera. |
Avtor: | Figeto [ So Nov 26, 2011 12:50 ] |
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1,8-meterski krožnik ne bi bil dovolj (samo) za 1N? |
Avtor: | urko [ So Nov 26, 2011 13:59 ] |
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Figeto tu boš našel več podatkov, vse pa je še v fazi testiranja, tako da so zgolj ugibanja... http://www.novisf.com/wbb3/digitalna-te ... -astra-1n/ |
Avtor: | Figeto [ So Nov 26, 2011 14:14 ] |
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Pardon, nisem mislil na tale nov satelit, temveč 2D (BBC One HD in ostalo). Andrews 1.8m http://www.satellitesuperstore.com/fixed-dishes.htm Imel bi ga izključno za Angleže. |
Avtor: | SatFaca [ So Nov 26, 2011 18:17 ] |
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Citiram: Pardon, nisem mislil na tale nov satelit, temveč 2D (BBC One HD in ostalo).
Andrews 1.8m http://www.satellitesuperstore.com/fixed-dishes.htm Imel bi ga izključno za Angleže. Ne bo šlo. |
Avtor: | Figeto [ To Feb 21, 2012 15:11 ] |
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Citiram: Changes to BBC services on satellite on 24th February 2012
Bomo videli. Iz 1N z mojo antenco lovim FTA ITV HD, res da, če je vreme OK.
Alix Pryde | 12:07 UK time, Monday, 20 February 2012</abbr> I wanted to share some information with you about an upcoming change to how we broadcast our satellite channels. You should not need to take any action, but I thought you might like to know what will be going on in the background. As some people may already be aware, the satellite operator SES Astra is making a number of changes to its fleet of satellites at the 28.2oEast orbital position over the next few years. These satellites are used for broadcasting television and radio channels (including those on Sky and Freesat) to homes in the UK. The first of these changes will take place during February when the Astra 1N satellite, which was launched last summer, replaces the Astra 2D satellite, which is coming towards the end of its life. The BBC currently broadcasts many of its television and radio services on Astra 2D, so as part of this replacement process BBC services that are currently located on Astra 2D will be moved across to Astra 1N. The services affected are: BBC One (including all National and Regional variants) BBC One HD BBC Two (including all National variants) BBC Three BBC Four BBC HD CBeebies CBBC BBC News BBC Parliament BBC ALBA BBC Radio 5 Live BBC Radio 5 Live Sports Extra The migration will be taking place during the early hours of the morning on Friday 24th February, between approximately 03:00 and 05:00 GMT. If you are watching or listening to BBC channels via satellite during this time you may experience some intermittent disruption to service. PVR recordings of BBC programmes made during this time may also be disrupted. The good news for satellite viewers is that the tuning details used for BBC services on Astra 1N following the migration will be the same as those used today for services on Astra 2D. The signal strength of the new satellite will also be the same or possibly better in some parts of the country. This means that the change of satellites should be invisible to most viewers - there should be no need to update or retune your set-top box. If viewers do experience any problems, your platform operator (which we have briefed about this change) would be best placed to provide assistance: Alix Pryde is the Director of BBC Distribution. |
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