C-band dish size
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What is a 36dbW signal? I don't understand your question? Generally speaking, on C-band dishes, for solid realiable reception, you need at least an 8' dish. I would personally recommend a 10' dish or bigger. For addequate experimental reception, a 6' dish. For hobbyist only reception, anything smaller than a 6' dish.
Al
Al
samc said:
If you want to be guaranteed to recieve signals on C band you need a dish that is at least 2 degree compliant. You need a dish that's 2 degree compliant because that how closely many of the satellites over the western hemisphere are spaced and the dish must be able to focus in on the one particular satellite your aiming for. Otherwise signals of the same frequency on adjacent satellites will interfere with the signals you want to recieve. To be 2 degree compliant on C band, a dish must be at least 8.5' in diameter. Larger is generally better. Yes, it's possible to sometimes "get by" with smaller dishes that aren't 2 degree compliant in some instances. But whenever that's possible, it's likely just because the satellite in question is in a portion of the arc where the nearest other satellite transmitting on that same frequency is farther that 2 degrees away, That might result when your aiming at a satellite that's in a portion of the arc where the spacing between satellites is greater, like for example Anif F1 or it might just be because the transponders on the next adjacent satellites that are on the same frequency are inactive at the time. If it's the later and those transponders ever do become active the person using the undersized dish is gonna have a problem. So, that's why you need at least an 8.5' dish.
Also note that signals strength really doesn't necessarily matter with regard to this issue, because signal strength is not the issue. Interference is. Therefore even if the signal you want to receive is "strong", if there's another "strong" signal on the adjacent satellite on overlapping frequencies youd likely have a problem with an undersized reflector.
Having said that there are some situations where an undersized reflector might work. One example might be some of that atlantic satellites which in some cases are spaced farther apart. Anyway, as to whether a smaller dish will work for the signal your interested in what satellite it's on and the spacing between it and the nearest other C band satellite might be a better thing to look at than signal strength.
It sounds like you're looking at the satellite coverage charts. You'll see that 36 dbW is a weaker, fringe area type of signal. I hope you also know that the dbW varies from satellite to satellite and even from transponder to transponder depending on your location. If you really want a solid signal within a 36 dbW area, you'll need a larger dish like a 12 footer with a very good feedhorn and LNB. You might want to check the other satellites to see if something with a stronger signal for your area will satisfy your desires. That way you can get by with a smaller dish. Just remember, only buy what you can afford. This is just a hobby. Have fun.
It would be better if you listed what sats/transponders you are trying to get.
Personally I use a 6" dish and looking at the Latin-American beam for PAS R1 I am only in the 34 - 36 dbW footprint, however I have no problem with the signal using the 6" dish.
Personally I use a 6" dish and looking at the Latin-American beam for PAS R1 I am only in the 34 - 36 dbW footprint, however I have no problem with the signal using the 6" dish.
It just depends, really. If you're looking at the hobbyist point of view, you can certainly try a 6ft dish. Will the signal go out when it rains? Maybe. For guaranteed reception, a 12ft or 14.5ft would work...and even then it's possible that a transponder or two might not be picked up depending on where you're at. I'm assuming you're wanting a blunt, sure fire answer, but unfortunately we're not at you're location and we don't know what equipment you might have access too and haven't tested out that equipment. And THEN, we don't know what satellite you want and what channels you want to receive.
Samc, if you go with a smaller dish it might be a good idea to install it on a pole and in a location which can handle a larger dish - one of at least 10' dia.
This way, should you be dissatisfied with the results of your initial installation, it will be relatively easy to upgrade.
This way, should you be dissatisfied with the results of your initial installation, it will be relatively easy to upgrade.
Thanks all for your informed responses. I am in South Africa and aiming at Pas 7/10. I get excellent signal strength (80-90%) but poor quality levels, as bad as 0-5% on some transponders but up to 50% on others. This is with a 1.8m mesh dish (about 6' ?) and a 17' LNB. I have the same problem with a 2.4m mesh dish (same LNB) aiming at BadrC (26.2E). Please advise.
Looking at the footprint maps I think it's pretty clear you are going to want a larger dish. How large I cannot say. Advice from someone with local experience would be your best bet. Perhaps an installer in your area would be willing to advise you.
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