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Re: Orbit 250 apogee
- Subject: Re: [amsat-bb] Orbit 250 apogee
- From: "Jens H. Jensen" <topcat@xxxxxxxxxxxxxxxxx>
- Date: Fri, 18 May 2001 21:21:12 +0200
- In-Reply-To: <001201c0df36$75196340$d6b4173f@house>
At 03:04 18-05-2001, you wrote:
--snip--
>Amateurs have published designs for 0.4 dB NF (28 K) amplifiers in QEX and
>Microwave Update and antennas can easily be made with sidelobes that are 15
>db down so that they only pick up 9 K of ground noise.
Does this mean that using an offset-dish instead of a primefocus dish is
actually an advantage, since the feed is usually NOT pointed at the ground,
but upwards, so that over-illumination will not "see" the ground?
How big is the ground-noise contribution exactly?
Is there anywhere I can read more about it?
73 de OZ1LRG
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