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Jan 12th, 2006 at 7:36pm
If your receive fails when you transmit then I suggest:
1. The transmitter may be about to burn out the LNB. You need the correct band pass/band stop filters to prevent unacceptable levels of TX signal getting into the LNB. Commonly, a "transmit reject filter" is located between the OMT and the LNB input. In some cases a transmit band pass filter is also inserted between the BUC and the OMT. See the figure on this page https://www.satsig.net/feed1.htm and read about feed diameters for the different models of Prodelin antennas.
2. Check the cable connectors. When the BUC transmits the DC current may increase. If the 4 braid connections are not perfect, some strange current paths can happen, which may result in low LNB volts.
Item 1 above reminds me of a cautionary learning story, as follows: If you ever find a dead LNB don't just go replacing it with a new one, otherwise you might end up with many burned out LNBs !
Regarding feed type you should have the larger diameter version as your dish is the long focal length type f/d=0.8 intended to achieve good polarisation purity over the -1dB beamwidth to meet ETSI euro specifications, which I don't agree with, incidentally.
Best regards, Eric.
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