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
--

"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

On Sun, 18 Jun 2006 12:38:55 GMT, "Dale Parfitt"
wrote:


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


Thanks, an interesting article and relevant.

However, sky noise / ambient noise remain of interest for G/T
evaluation.

Thanks
Owen
--

Owen Duffy wrote:


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

Owen
--

Several of the EME software programs, such as TRACKER for MS machines,
or Palmtrack for Palm OS, will give the noise temperature at several
frequencies. Google for "EME tracking scheduling".

You could also get help from one of the 2 EME nets on 20m. They run
from approximately 1000 through 1230 Eastern time on 14345. If you
can't check in, you can listen to the net on the first link at
http://taring.org using WMP or any other mp3 streamer, and you can email
your question to Joe, K1RQG_ _@_ _aol.com (remove the clutter to use)
and he will likely get the net to respond with lots of information for
you. Checking there would get you the best answers on sky noise.

Alternatively, the sun is easy to find, and the numbers are published
daily for at least 2 frequencies. The problem is extrapolating those
numbers to as low as 2 meters. Discussions recently say the best known,
most used, equation probably is not correct, even at 1296, and will be
even less accurate at 432, let alone 2 meters. There was a corrected
one suggested, but I would take any of them as untrustworthy at this
time. Again, the EME net may be of help, as many net participants take
regular, even daily, sun noise measurements at 1296. They can also give
you tips on avoiding errors and calibrating.

tom
K0TAR

Tom Ring wrote:

Owen Duffy wrote:


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

Owen
--


Several of the EME software programs, such as TRACKER for MS machines,
or Palmtrack for Palm OS, will give the noise temperature at several
frequencies. Google for "EME tracking scheduling".

You could also get help from one of the 2 EME nets on 20m. They run
from approximately 1000 through 1230 Eastern time on 14345. If you

Oops, forgot to add - on Saturday and Sunday.

tom
K0TAR

Dear Owen:

W8PIL and I (then W8TBZ) published a paper on this subject in QST using
radio astronomy information. As I recall, the article was published about
June of 1961. He has since retired from NRL and I am still going.

73, Mac N8TT

--
J. Mc Laughlin; Michigan U.S.A.
Home:
"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
--

Dear Group:
While purging my office for twelve hours today in preparation for a move
to another office, I came upon another article that might be of use:
"136 MHz/400 MHz Radio-Sky Maps" by Ralph E. Taylor; Proc. of the IEEE;
April 1973, pp469-472

Not everything can be found with Google.
73, Mac N8TT

"J. Mc Laughlin" wrote in message
...
Dear Owen:

W8PIL and I (then W8TBZ) published a paper on this subject in QST using
radio astronomy information. As I recall, the article was published about
June of 1961. He has since retired from NRL and I am still going.

73, Mac N8TT

--
J. Mc Laughlin; Michigan U.S.A.
Home:
"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
--

In message , Owen Duffy
writes

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


Chart on page 94

http://radar04.lightsky.net/tutorial...o.to.radar.pdf

Gives bounds of sky temp for different antenna elevations as a function
of frequency. Some of the EME programs give it.

Brian
--
Brian Howie

Owen Duffy wrote in
:


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?

I'm reasonably happy with a 2m receiver that has a noise figure of 1.5db
or less. A good antenna system should be able to exceed the noise floor
of such a receiver, pointed just about anywhere in the sky. The galactic
plane should be enough


--
Dave Oldridge+
ICQ 1800667

I only scanned the replies so far, so may have missed a similar
reference, but recent editions of "Reference Data for Engineers" (used
to be ITT Reference Data for Radio Engineers) in the "noise" chapter
have a couple "Radio-sky maps," one for 136MHz and one for 400MHz.
There's a great deal of variation, depending on where you point your
antenna (assuming a very narrow beamwidth). On 400MHz, at about 18
hours RA and -30 degrees declination, you'll get about 280 kelvins; at
10 hours and +30 degrees, you'll get about 15 kelvins. On 136MHz in
the same two directions, it's about 3600 and 200 kelvins. Perhaps such
sky maps are available online somewhere for a wider range of
frequencies.

Cheers,
Tom

Owen Duffy wrote:
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
--