Sun burst
 

Aussiland television was turned off for a short while yesterday.
Statement made that there was a sunburst aproaching the satellites!
They were only off for a short while but it would appear the sunspot
cycle has become alive!

Sun burst
 

Art Unwin wrote:
Aussiland television was turned off for a short while yesterday.
Statement made that there was a sunburst aproaching the satellites!
They were only off for a short while but it would appear the sunspot
cycle has become alive!

http://www.swpc.noaa.gov/alerts/alerts_timeline.html

No X-ray events, radio burst alerts, geomagnetic warnings, electron
flux alerts, proton flux alerts, sunspots, or anything else.


--
Jim Pennino

Remove .spam.sux to reply.

Sun burst
 

wrote in message
...



http://www.swpc.noaa.gov/alerts/alerts_timeline.html


Good one. Please also try these links; they provide solar observations and
analysis.

http://spaceweather.com/

http://umbra.nascom.nasa.gov/eit/eit_full_res.html

http://dx.qsl.net/propagation/ This one puts the Solar Flux number at the
top.

Sun burst
 

Sal M. Onella wrote:

wrote in message
...



http://www.swpc.noaa.gov/alerts/alerts_timeline.html


Good one. Please also try these links; they provide solar observations and
analysis.

http://spaceweather.com/

http://umbra.nascom.nasa.gov/eit/eit_full_res.html

http://dx.qsl.net/propagation/ This one puts the Solar Flux number at the
top.

If you run Firefox, there is the Propfire extension that puts semi-real
time info at the bottom of the browser.


--
Jim Pennino

Remove .spam.sux to reply.

Sun burst
 

On Aug 29, 10:00*am, wrote:


No X-ray events, radio burst alerts, geomagnetic warnings, electron
flux alerts, proton flux alerts, sunspots, or anything else.





Perth, Western Australia

Foxtel went off air Thurs morning 5am approx for a short
time with a notice saying it was due to solar activity.

Derek

Sun burst
 

"Art Unwin" wrote in message
...
Aussiland television was turned off for a short while yesterday.
Statement made that there was a sunburst aproaching the satellites!
They were only off for a short while but it would appear the sunspot
cycle has become alive!

no solar activity... eclipse season maybe? for a short time each spring and
fall geostationary satellites happen to line up with the sun's path,
stations that have no backup satellite may lose signal when their satellite
lines up with the sun for a few minutes and the sun's noise blocks the
satellite signal.

Sun burst
 

On Aug 29, 3:57*am, "Dave" wrote:
"Art Unwin" wrote in message

...

Aussiland television was turned off for a short while yesterday.
Statement made that there was a sunburst aproaching the satellites!
They were only off for a short while but it would appear the sunspot
cycle has become alive!

no solar activity... eclipse season maybe? *for a short time each spring and
fall geostationary satellites happen to line up with the sun's path,
stations that have no backup satellite may lose signal when their satellite
lines up with the sun for a few minutes and the sun's noise blocks the
satellite signal.

Exactly right. Back in 1986, I worked for a bank data processing
service in Bellevue, WA. I set up a leased data line between our site
and two banks in Hawaii. The line went to San Francisco then via
satellite to Hawaii. Twice a year the service was stopped for about
1/2 hour while the sun passed through the focus of the satellite dish
in Hawaii. I don't think it affected the SF end of the link. AT&T
always called to warn of the disruption.

Paul

Sun burst
 

On Sat, 29 Aug 2009 08:35:49 -0700 (PDT), KD7HB
wrote:

Exactly right. Back in 1986, I worked for a bank data processing
service in Bellevue, WA. I set up a leased data line between our site
and two banks in Hawaii. The line went to San Francisco then via
satellite to Hawaii. Twice a year the service was stopped for about
1/2 hour while the sun passed through the focus of the satellite dish
in Hawaii. I don't think it affected the SF end of the link. AT&T
always called to warn of the disruption.

If the dish is pointed at a geosynchronous satellite, it should affect
both ends of the link, but at different times of the day. Actually,
for the typical DBS 0.7 meter dish, the outage appears for about 3-5
days and lasts about 5-10 minutes.

I live in a rather dense forest, where finding a "hole" in the tree
canopy for DBS reception is tricky. The best way to locate an antenna
is to check where the sun shines through the trees during the times of
the solar outage. Where there's light on the roof, there's a path to
a specific satellite. I've been posting bi-annual tables to help with
the calcs (when I remember to do so). For example:
http://groups.google.com/group/ba.mountain-folk/msg/69c19369b4a5ffde?dmode=source
It's also a good quality test for dish location. If the dish is
showing tree branch shadows on its face during the solar outage, it
needs to be moved (or the trees trimmed).

Assorted calculators:
http://www.intelsat.com/resources/satellitedata/sundata.asp
http://www.satellite-calculations.com/SUNcalc/SUNcalc.htm
http://www.satellite-calculations.com/Satellite/SUNcalc.htm
http://www.ses-americom.com/americom_2008/siteSections/tools/sunoutage/index.php
The Panamsat derived calculators have a bug in them where it will not
accept dish diameters smaller than 1 meter. For small 0.7 meter DBS
dishes, just use 1 meter and proportionally reduce the outage
duration.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Sun burst
 

In article
,
derek wrote:

On Aug 29, 10:00*am, wrote:


No X-ray events, radio burst alerts, geomagnetic warnings, electron
flux alerts, proton flux alerts, sunspots, or anything else.





Perth, Western Australia

Foxtel went off air Thurs morning 5am approx for a short
time with a notice saying it was due to solar activity.

Derek

This just shows that Foxtel's Public Media types don't understand the
technology that they use..... Sun Outages happen twice a year for a
couple of days in a row each time. The Sun's Track lines up behind the
GeoSync Sats position, in relation to the receiving Antenna, and the
sun's noise overwhelms the Signal in the receiver. This whole deal is
nothing NEW, just misunderstood by the Bloody Wonk, who wrote the Press
Release....

Sun burst
 

On Aug 29, 1:31*pm, You wrote:
In article
,



*derek wrote:
On Aug 29, 10:00*am, wrote:

No X-ray events, radio burst alerts, geomagnetic warnings, electron
flux alerts, proton flux alerts, sunspots, or anything else.

* Perth, *Western Australia

* * *Foxtel went off air Thurs morning 5am approx for a short
time * * *with a notice saying it was due to solar activity.

*Derek

This just shows that Foxtel's Public Media types don't understand the
technology that they use..... Sun Outages happen twice a year for a
couple of days in a row each time. *The Sun's Track lines up behind the
GeoSync Sats position, in relation to the receiving Antenna, and the
sun's noise overwhelms the Signal in the receiver. This whole deal is
nothing NEW, just misunderstood by the Bloody Wonk, who wrote the Press
Release....

Let us put it into perspective. I used the term "sunburst" because I
thought it was an isolated strong sun spotas it is so early in the
cycle. But if they used the term sunburst as refering to its noise
level then no harm done as far as notifying the viewing public. Except
for me it appears that hams in general are aware of the true phenomina
and are not expecting the Sun to fall from the sky. A lot of excellent
explanations came thru and I enjoyed them. Ofcourse, if it a
subsidiary of FOX in the US then pile it on by all means
Thanks

Sun burst
 

Hi Paul

Just for interest what is the S/N margin with most commercial satellite
systems and how "strong" is the sun relative to those levels? I would
assume the margin for an end use TV viewer would be less than this?

Cheers Bob VK2YQA

KD7HB wrote:


Exactly right. Back in 1986, I worked for a bank data processing
service in Bellevue, WA. I set up a leased data line between our site
and two banks in Hawaii. The line went to San Francisco then via
satellite to Hawaii. Twice a year the service was stopped for about
1/2 hour while the sun passed through the focus of the satellite dish
in Hawaii. I don't think it affected the SF end of the link. AT&T
always called to warn of the disruption.

Paul

Sun burst
 

Bob Bob wrote in news:7kjom6-m74.ln1
@p400bob.personal.cox.net:

Hi Paul

Just for interest what is the S/N margin with most commercial satellite
systems and how "strong" is the sun relative to those levels? I would
assume the margin for an end use TV viewer would be less than this?

Bob, it is a few years since I did satellite path designs... but relying
on memory...

Most satellite TV here is digital, and the issue becomes a C/N ratio that
delivers acceptable error rates after FEC. The characteristic has a knee,
and error rates degrade rapidly at the knee. Satellite facilities are so
expensive, that operation is usually quite close to the knee... save a
margin for such things as weather, and that margin is usually no more
than necessary for most but not all such variables. You don't need much
Sun noise to ruin performance. (BTW, I think that the satellites used for
this purpose here are bent pipe technology (aka linear transponder), the
uplink is not regenerated on the bird.)

The issues discussed in the thread seem to mix up two distinct effects.
If the earth station sees the sun behind the satellite, C/N may be
degraded sufficiently to disrupt digital services. At equinoxes, the bird
rotates into the earth's shaddow and some times of day, and that means it
has to operate exclusively on battery, and if it uses the Sun for antenna
tracking, it will need to change reference. Using CO2 for a reference
(earth's atmosphere) is not reliable if the Moon appears from behind the
earth, the antennas could track the moon. I am not up to date on the
latest tracking references... but I am sure the Sun is still a good
reference, good contrast, visible most of the time.

Owen

Sun burst
 

"Dave" wrote in message
...

"Art Unwin" wrote in message
...
Aussiland television was turned off for a short while yesterday.
Statement made that there was a sunburst aproaching the satellites!
They were only off for a short while but it would appear the sunspot
cycle has become alive!

no solar activity... eclipse season maybe? for a short time each spring
and
fall geostationary satellites happen to line up with the sun's path,
stations that have no backup satellite may lose signal when their
satellite
lines up with the sun for a few minutes and the sun's noise blocks the
satellite signal.


Don't know if they still do it, but once upon a time HBO produced a program
guide for their home-sat subscribers. In the issues for April and October
(I think) they'd always advise us about sun outages and give us the
predicted dates, based on our latitude.

Sun burst
 

"Bob Bob" wrote in message
...
Hi Paul

Just for interest what is the S/N margin with most commercial satellite
systems and how "strong" is the sun relative to those levels? I would
assume the margin for an end use TV viewer would be less than this?

Cheers Bob VK2YQA

The Carrier-to-Noise ratio for analog TV was recommended to be 8db or better
for a noise-free picture (~50dB S/N after demodulation). With my 10-foot
dish, the peak of a solar outage would render the picture unrecognizable as
such for up to a minute. This means the sun had to be about 4 dB stronger,
since I recall 4 dB C/N was no picture at all. I hope this helps.

Sidelight: Analog degradation showed up as a type of video snow known as
"sparklies," usually in brightly colored areas. The beginning of a solar
outage would always be the appearance of sparklies.

I had the analog system for almost 20 years, so I was pretty conversant with
these periodic outages.

Digital, I don't know. I have a small dish setup but I haven't played with
it in years.

Sal