On Wed, 21 Dec 2005 00:27:31 +0100, "Henry Kiefer"
wrote:

"K7ITM" schrieb im Newsbeitrag
oups.com...
I'm curious, what sorts of things do amateurs do that really need
better than a 1dB noise figure on 2 meters? I can understand it on
higher frequencies, but I'd have thought that galactic noise, at least,
would be a limiting factor on 2 meters.

Is that galactic noise measured on a wide bandwidth antenna?
What if it is very narrow band?

At 2 m the Sun is quite noisy, in addition the noise from the stars in
our Milky Way galaxy will contribute quite strongly to the background
noise levels with noise temperatures of several hundred Kelvins if the
antenna is pointing at the galactic plane.

However, if the antenna is pointing away from both the Sun and the
Milky Way, the noise levels are lower and thus, if you try to receive
a satellite in that direction, a low noise preamplifier will help. Of
course, this can be more easily observed on 70 cm and 23 cm, in which
the "cold sky" noise levels are even lower.

Paul OH3LWR