Re: I'm I likely to hear anything off the moon? Newbie question


SAM JEWELL
 

OK Nick,
A bit far away for me to check it for you. Can you find someone nearby who can do a noise figure measurement for you?
I don’t remember what noise difference you see between a 50R termination on the LNA and cold sky?
Assume that the termination is at 290k, or very close. Cold sky, at the right time, angle etc should be about 4-10k
Use VK3UM or Appcad to see what you should get in a perfect system (0dB system noise figure)
It will be less due to ground noise pick up on lobes of the antenna, total receiver system noise figure and any significant second stage contribution. 
How far short of this theoretical value are you?
That will tell you a lot about your system.
I suspect that it is either the antenna or the receiver, but without some measurements it is hard to be sure which to look at.

73 de Sam

On Friday, June 28, 2019, 2:48 pm, Nick Gregory via Groups.Io <nickg0hik@...> wrote:

Hi Sam,

The LNA is connected  with a very short lead, so fractions of a dB loss there. 

The LNA is supposed to be 0.8dB noise factor.

Im in Cumbria IO84.

Nick G0HIK

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