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Old June 18th 06, 01:38 PM posted to rec.radio.amateur.antenna
Dale Parfitt
 
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Default Sky noise temperature - 2m, 70cm, 23cm


"Owen Duffy" wrote in message
...

Googling about turns up a little, and only a little information on the
expected sky noise temperature on 2m, 70cm, 23cm.

The information isn't very consistent. For example, articles that talk
about the sky noise below 200MHz being 100K or more, and amateur
articles talking about sky noise at 144MHz being "hundreds of
degrees".

Similary, for 70cm a broad brush figure of 45K seems to be used, and
others talk about 20K away from the galactic plane and 60K on the
galactic plane. (Yes, they will be blurred together with a low gain
antenna.)

Some discussions treat the "sky noise temperature" as if it includes
spillover noise (eg in cold sky / hot earth measurements).

Can anyone recommend a reliable source of sky noise characteristics
for these bands.

Additionally, I am interested in the range of ambient noise levels
experienced for these bands for traditional DX activity (ie antennas
at zero elevation.

Alternatively, are satellite beacons a reliable source for measuring
station receive performance?

Or... is there some other better way of measuring station receive
performance?

Owen
--


Hi Owen,

I seem to recall around 30K-40K for cold sky.

At 432 and above, everyone I know is using sun noise to evaluate system
performance. Have a look at K5SO's site:
http://www.k5so.com/Sun_noise.html

Most of us on 1296 EME use a GR1236 IF meter for sun measurements. Easily
resolves 0.1dB.

73,

Dale W4OP