Quote:
Originally Posted by SatJunkie97
is it possible to get 97w and 123w on one 36 inch dish?
i was planning on aiming the dish at 110w first so its kinda in the middle, then using a fully adjustable LNB bracket place one LNB at each side of the center LNB, so basically there will be no LNB on the dish arm itself, is this possible? or is the span between them too great?
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The 36" dish is designed for optimum efficiency with one feed (LNB) at its focal point. When you place your LNBs at some distance to the left and right of the normal focal point (to get 97 and 123), the gain you will get is much less than a 36" dish can deliver when it is optimized. It may only be equivalent to an 18" or 20" dish. That is well below the 30-33" minimum size to get good S and Q readings from 123 and 97. Another degrading factor is cross-polarization discrimination. Even after you twist your LNBs for optimum reception of the desired V or H polarization on each satellite, the rejection of the unwanted H or V polarization will be much less than the typical value of 20-25 dB. As you move away from the maximum gain point, the cross-pol discrimination drops off radically. Transponder signal strengths on both 97 and 123 vary much more than on 110 and 119, because the uplinks feeding them are not co-located. Adjacent transponders are cross-polarized to minimize interference. So, you may have a situation where you're trying to receive a weak transponder when there is a stronger one on the next higher or lower frequency. With your poorer than normal cross-polarization discrimination, interference from the undesired adjacent transponder is likely.
But if playing around with antennas is your hobby (as it is with me), give it a try, and let us know if you are successful.