We are talking KU band, I just checked it says minimum 130cm
ya my bad. i had the c-band map loaded. when i did ku it said 150cm recommended with a 38dbw eirp.
Redilyn and Beavs,
I looked the EIRP information up through satbeams.com - this is the site that I have been using predominately if not exclusively for the most accurate information regarding EIRP values.
For the general area around Kentsville Nova Scotia, they are recommending a minumum dish size of 150 cm or 59.1 inches for the 38 dBw EIRP level that is estimated there.
I trust their recommendations within some measure of reasoning. I have found that I can obtain fair quality signals with certain combinations of dish/LNBF when they recommend a minimum that is larger than the dish that I am using. Therefore, some recommendations are left slightly to conjecture and dependant upon the combination of the dish and LNBF that is being used.
As Brian Gohl (SatelliteAV) elluded to, there is a definite advantage to matching the LNBF with the dish reflector. The Ku Band LNBFs have a "mini" scalar ring built in to the LNBF assembly. These are not noticeable unless you disect the LNBF, but they are present. Matching your LNBF to your dish is not an easy task to do on your own. It is best to ask the dish manufacturer to recommend the LNBF that is matched to their dish. They have done all the research in advance and that can save you a lot of headaches trying to figure it out yourself. Of course, if you are really into this hobby in a major way, this subject would (or may) be something that you would like to investigate in more depth for your own reasons - to learn for the sake of expanding your knowledge base. Well, you understand what I mean by that, but personally I don't get that involved with the engineering aspects in that fine of a sense.
Redilyn, from my own personal experience with the Winegard DS3101 dish, I found that this dish was very sensitive to the alignment with the satellite when I used it with the Invacom QPH-031 LNBF. When I did have it aligned perfectly, the signal quality was exceptional, but it was a very fine window of alignment and if I just tweaked the dish or the LNBF slightly, I nearly lost the signal altogether. It was very touchy.
I honestly had better luck with my Winegard DS2076 (76 cm) dish and the Invacom QPH-031 LNBF as opposed to the DS3101 (1 M) dish with the identical LNBF. I have now been using a 1.2 M GeosatPro dish with the Invacom QPH-031 and it is slightly more effective and efficient than either Winegard dish, but it is now also that much larger that I have some wind loading concerns which causes my signal to vary when we have strong, gusty and variable direction winds. The smaller 76 cm Winegard dish was much more forgiving in this regard, it allowed me a greater "fudge factor" for alignment.
Obviously, with the recommended dish size for your area for that particular satellite, you probably wouldn't want to use a 76 cm dish as that would most likely be too small (half of what is recommended by satbeam's site).
Just FYI, with my AZBox Premium Plus receiver, the 1.2 M GeoSatPro antenna and an Invacom QPH-031 LNBF and my location in the Omaha, Nebraska USA area, I am reading 88-94% quality from TP 12053 MHz (V) with a SR of 6890 Ks/S (which is the NBC MUX). Also, today, it is heavy overcast, drizzling rain from time to time and windy. For my area, Satbeams.com recommends a minimum dish size of 70 cm or 27.6 in (48 dBW EIRP value estimated).
I don't know how much my information will help you - if at all, but it will provide you with some data to ponder and compare and some ideas regarding what you might wish to research for your own system. I wish you fun and good luck!
RADAR
