ABS-S Advanced Broadcasting System-Satellite / spectral analysis
Chinasat 9 at 92.2°E-Asian footprint : 23.10.2010 - spectrum analysis of ABS-S packets
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--- four packets in the format of ABS-S : 11 840-11 960 MHz-Left-circular vector ---
click for enlarge
Date of measurement : 23.10.2010 / the period of time 7.00 - 17.30 /
- Weather conditions : cloudy -
- defining the status of reception -
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-- adverse weather conditions as the main factor that has direct relationship on the quality of the resulting reception (at the size
of the elevation angle of only 2.8°) significantly influenced the results of measurements,so I can not objectively compare the quality
of reception in April this year during clear weather with current grades.I have identified significant changes in the level of signal
flow EIRP, which is permanently changed in a wide range of amplitudes of quality, which can be expressed in relative terms as
follows:because of that I have no measuring device that can analyze the quality of reception in the format of ABS-S,current status
of the signal reception point I derived from the relative quality indicator in Satellite Receiver.During the previous measurement
amplitude reached quality levels around 28% and significantly less fluctuated.At present, the quality reaches peak levels
up to 50-60% ! but the length of a stable carrier lock format ABS-S is significantly reduced compared with the months of April this
year and takes only seconds to tens (the last measurement I also identified sections in length from 15 to 20 minutes with a stable
lock carrier but at half the quality).Significant impact on the possibility of locking the carrier also has an enhanced version of the
third generation of dxsatcs waveguide line which I have proposed.
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--- four packets in the format of ABS-S : 11 840-11 960 MHz_full range of the spectrum L ---
click for enlarge
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--- four packets in the format of ABS-S : 11 840-11 960 MHz_ LIVE video ---
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Chinasat 9 at 92.2°E : 28.11.09-spectrum analysis of packets in the standard ABS-S
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--- Practice of collecting and summarizing data ---
--- Date of measurement : 28.11.2009 ---
Collection and summary of measured data and analysis that I performed in a continuous mode during only one day ( 28th November 2009)
between 2pm and 6pm under variable weather conditions . For each ABS-S carrier in the frequency spectrum, I spent only
5 minutes, during which I have carried a record peak of gross signal POW-V levels.
Click on the picture for high resolution
description of the spectrum : four packets in the standard ABS-S with bandwidth 36 MHz,which are constantly present in the
frequency spectrum of a circular vector L in the place of income Lučenec _ Slovakia .
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Chinasat 9 at 92.2°E - KU footprint - ABS-S carrier No. 1: f = 11 840 L
Click on the picture for high resolution
description of the spectrum : depending on weather conditions at RF signal transmission path I can define the following :
on 28.11.2009, within a period of 30 minutes, the average POW-The levels varied in amplitude from 950 uV to 1.4 mV, with
regular peaks of pmin = 800 uV after Phigh = 1.6 mV, where the threshold ABS-S levels around the POW-V = 700uV been
exceeded only once in 5 seconds, which is reflected in a loss of detection of the carrier transmission.
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Chinasat 9 at 92.2°E - KU footprint - ABS-S carrier No. 2: f = 11 880 L
Click on the picture for high resolution
description of the spectrum : POW-V amplitude changes in the levels of the carrier transmission in response to the quality of income
that I could not express such an objective in the unit MER, PER ... but only on the basis of biased ratio as a percentage of the quality
of ABS-S receiver, reaching almost identical levels as the carrier of f = 11 840 MHz, but during 30 minutes the threshold level
had exceeded three times the length of a few seconds.
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Chinasat 9 at 92.2°E - KU footprint - ABS-S carrier No. 3: f = 11 920 L
Click on the pictute for high resolution
description of the spectrum : measurements during the oscillation of the carrier in the range of levels within a period of 30 min in
combination with visual inspection of images from ABS-S Receiver confirmed POW-average decline in the levels range from
Pmin = 800 uV to Phigh = 1.2 mV but the passage through the threshold occurred regularly once to twice in a period of 5 minutes .
Chinasat 9 at 92.2°E - KU footprint - ABS-S carrier No. 4: f = 11 960 L
Click on the picture for high resolution
description of the spectrum : the measurements of the carrier transfer to f = 11 960 MHz, I identified a nearly identical amplitude
of the oscillating from 800 uV to 1.2 mV as the frequency f = 11 920 MHz and also there is an irregular crossing of a threshold
level of one to two times over a period of 5 minutes .
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Roman Dávid - author & founder
mail : roman.david@dxsatcs.com