RadioBanter - RFI caused by BPL soon resolved ?

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- - RFI caused by BPL soon resolved ? (https://www.radiobanter.com/equipment/12101-rfi-caused-bpl-soon-resolved.html)

"RVMJ" wrote in message
...

As the result of a deliberate manoeuvre, the Galileo spacecraft
collided with the planet Jupiter at an estimated time of 12:49:36 PDT
on September 21st this year. Signal had been lost at 12:43:14 pm as
Galileo passed behind Jupiter at a height of 5768 miles. Descent angle
was 22 degrees and the impact speed 108,000 mph, a little more than
the 106,500 mph of the Galileo probe, which entered Jupiter's
atmosphere in December 1995.

Galileo's transmitter had an output power of between 15 to 20 watts to
an antenna having 7 db of gain. Received power at the Deep Space Net
was -167 dBm.

The DSN receivers track frequencies with extreme precision. The
frequency gate for Galileo was normally about 0.3 Hz for a carrier
frequency of 2295 MHz, but could be widened to 3 Hz for a moon flyby
or planetary impact.

Normally, Galileo put all the transmitter power into data sidebands
plus or minus 360 kHz from the nominal carrier. This is called
suppressed-carrier working, or a modulation index of 90 degrees.
However, a pure-tone carrier would be less-difficult to track near
impact, so 5.5 hr before impact the modulation index was shifted to 60
degrees. This has the effect of putting more power into the carrier at
the expense of that in the data sidebands.

Four hours before impact the data rate was changed from 20 bps to 32
bps in order to gather as much science. However, Galileo's engineers
noticed that their real-time displays had stopped working.
Wide-spectrum recorders had captured the raw signals, and the
engineers are now using special decoders to find the data, which is 5
dB below the noise level. Obviously a bunch of Amateurs.....NOT.

And all without Gareth's "Big K" ;-)

--
73
Brian
G8OSN
www.g8osn.org.uk
www.amateurradiotraining.org.uk for FREE training material for the UK
Foundation and Intermediate Licences
www.phoenixradioclub.org.uk - a RADIO club specifically for those wishing
to learn more about amateur radio

"Airy R. Bean" wrote in message
...
What is the problem here? _REAL_ Radio Hams work with
signals that are deep in the noise all the time. There might be
a concern here by CBers who want S9 BBC quality, but
not for Radio Hams!

Is that why CBers use echo boxes so they can sound like SSB voices, without
the carrier insertion?

ak

"RVMJ" wrote in message
...
Airy R. Bean wrote:

"Thierry" wrote:

...
Wide-spectrum recorders had captured the raw signals, and the
engineers are now using special decoders to find the data, which is 5
dB below the noise level. Obviously a bunch of Amateurs.....NOT.

Mmm?
There is a software accessible to amateurs that can detect signal 10 dB
below the noise : FFTDSP
See my commentaries on http://www.astrosurf.com/lombry/soft-calc.htm#FFTDSP
and a small review in French at the end of this page,
http://www.astrosurf.com/lombry/sate...tificiels5.htm
It is not much different from a SETI application.

Thierry
ON4SKY, LX3SKY

--
from
RVMJ
(at) Bigfoot (dot) com

"Airy R. Bean" wrote in message
...
Taking the lead from the suppressors that were developed to
deal with the supposedly random Russian "Woodpecker"
is that necessarily the case?

The "Woodpecker" wasn't "supposedly" random, it was pseudo random - not the
same thing at all.

In fact, successive pulses even had 'glitches' in the same position - an
artefact of the way the short pulses were generated from a long (31 or 33-
it was along tome back) bit sequence.

As the whole idea was to give a predictable "compressed pulse" the thought
that is could be "supposedly" random is not creditable.

--
73
Brian
G8OSN
www.g8osn.org.uk
www.amateurradiotraining.org.uk for FREE training material for the UK
Foundation and Intermediate Licences
www.phoenixradioclub.org.uk - a RADIO club specifically for those wishing
to learn more about amateur radio

On Mon, 20 Oct 2003 21:11:45 +0100, "Brian Reay"
wrote:

www.phoenixradioclub.org.uk - a RADIO club specifically for those wishing
to learn more about amateur radio

still waiting for the name of someone in the phoenix radio club that i
can contact to learn more about morse code.

"Zoran Brlecic" wrote in message
...
snip
[Gasp!]... but that could mean one thing only: president Wolf... I mean
president G.W.Bush and his cronies lied to the American people!!!

Hmm, politicians lying to their constituents to the point of having
hundreds of lost lives in order to satisfy the lobby of a foreign
country, while filling their pockets in the process? No ****ing way!
There's gotta be a more rational explanation. This must be a vast

liberal-anti-Christian-communist-leftist-atheist-terrorist-Clinton-UN-Franco-Ger
man
conspiracy. Yeah, that's what it is. Whew! Life makes sense again.

73 ... WA7AA

You're an American aren't you ??

Steve Terry