Telstar

Forum o satelitski, kabelski, zemeljski in IP TV
Danes je So Apr 27, 2024 9:28

Vsi časi so UTC+02:00 Evropa/Ljubljana




Napiši novo temo  Odgovori na temo  [ 50 prispevkov ]  Pojdi na stran Prejšnja 1 2 3 4 5
Avtor Sporočilo
 Naslov prispevka:
OdgovorObjavljeno: Pe Nov 11, 2011 20:17 
Odsoten
Site Admin
Uporabniški avatar

Pridružen: Sr Nov 26, 2003 9:37
Prispevkov: 10537
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.

_________________
10km SV od Kranja (na robu ravnine ob vznožju Krvavca) koordinati 14.45386 in 46.26856
Home made sprejem DVB-C Krim
Ati Radeon HD 4350 ful HW h.264 dekodiranje (0% CPU)


Na vrh
   
 Naslov prispevka:
OdgovorObjavljeno: Pe Nov 11, 2011 20:38 
Odsoten

Pridružen: Po Feb 16, 2004 13:13
Prispevkov: 574
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


Na vrh
   
 Naslov prispevka:
OdgovorObjavljeno: Pe Nov 11, 2011 21:51 
Odsoten
Site Admin
Uporabniški avatar

Pridružen: Sr Nov 26, 2003 9:37
Prispevkov: 10537
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.

_________________
10km SV od Kranja (na robu ravnine ob vznožju Krvavca) koordinati 14.45386 in 46.26856
Home made sprejem DVB-C Krim
Ati Radeon HD 4350 ful HW h.264 dekodiranje (0% CPU)


Na vrh
   
 Naslov prispevka:
OdgovorObjavljeno: Pe Nov 11, 2011 22:25 
Odsoten

Pridružen: Pe Feb 06, 2004 12:02
Prispevkov: 462
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.

_________________
Orbitron SX-10 3.1 m (87.5E - 61W)
Fracarro Blu920+ (360°)


Na vrh
   
 Naslov prispevka:
OdgovorObjavljeno: So Nov 12, 2011 21:03 
Odsoten
Site Admin
Uporabniški avatar

Pridružen: Sr Nov 26, 2003 9:37
Prispevkov: 10537
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.

_________________
10km SV od Kranja (na robu ravnine ob vznožju Krvavca) koordinati 14.45386 in 46.26856
Home made sprejem DVB-C Krim
Ati Radeon HD 4350 ful HW h.264 dekodiranje (0% CPU)


Na vrh
   
 Naslov prispevka:
OdgovorObjavljeno: So Nov 26, 2011 12:50 
1,8-meterski krožnik ne bi bil dovolj (samo) za 1N?


Na vrh
   
 Naslov prispevka:
OdgovorObjavljeno: So Nov 26, 2011 13:59 
Odsoten

Pridružen: Sr Jun 28, 2006 11:22
Prispevkov: 1195
Kraj: Notranjska
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/

_________________
Hisense 43A7500F 4K UHD
Beelink GT1 MINI
A1 optika


Na vrh
   
 Naslov prispevka:
OdgovorObjavljeno: So Nov 26, 2011 14:14 
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.


Na vrh
   
 Naslov prispevka:
OdgovorObjavljeno: So Nov 26, 2011 18:17 
Odsoten

Pridružen: Pe Feb 06, 2004 12:02
Prispevkov: 462
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.

_________________
Orbitron SX-10 3.1 m (87.5E - 61W)
Fracarro Blu920+ (360°)


Na vrh
   
 Naslov prispevka:
OdgovorObjavljeno: To Feb 21, 2012 15:11 
Citiram:
Changes to BBC services on satellite on 24th February 2012


Alix Pryde | 12:07 UK time, Monday, 20 February 2012</abbr>
Slika

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.
Bomo videli. Iz 1N z mojo antenco lovim FTA ITV HD, res da, če je vreme OK.


Na vrh
   
Prikaži prispevke prejšnjih:  Razvrsti po  
Napiši novo temo  Odgovori na temo  [ 50 prispevkov ]  Pojdi na stran Prejšnja 1 2 3 4 5

Vsi časi so UTC+02:00 Evropa/Ljubljana


Kdo je na strani

Po forumu brska: 0 registriranih uporabnikov in 30 gostov


Ne morete pisati prispevkov v temi
Ne morete odgovarjati na teme v forumu
Ne morete urejati prispevkov v temi
Ne morete brisati vaših prispevkov forumu
Ne morete dodati priponk prispevkom

Pojdi na:  
cron
Teče na phpBB® Forum Software © phpBB Limited