SOME RETROENGINEERING OF THE SIGNALS BROADCASTED FROM THE STARLING IP NETWORK Part 1

 After the three inctroductory publications how to practically play easily receiving the Starlink satellite signals :

https://air-radiorama.blogspot.com/2022/01/ricevere-i-beacon-delle-rete-starlink.html

https://air-radiorama.blogspot.com/2022/01/come-vedere-il-tempo-reale-la-posizione.html

https://air-radiorama.blogspot.com/2022/01/guardiamo-dentro-ad-un-terminale.html

 I have continue to improve to derive much more parameters .

To do this I first found the best possible low cost solution so receive the signals with the best avalability and C/N ( Carrier Noise ) possible with no tracking possible and even the worst conditions possible to have some receptions ,at least of the beacons, in very simple or broad conditions .

This accounts some strange and crazy architecture tested seen in the following pictures :

With a 90 cm dish randomly pointed , possible some times , for short time , of course high signals 

Outdoor  45 degrees and zenith , possible easily , beacons .

Same 45 degrees as outdoor , same postion but impossible indoor , probably attenuation from double glasses , need more investigation

                                                    

Small horn zenith , not bad .

Bigger horn at zenith , better signals , but less time of receiving .

Dipole . No way .

Log periodic pointed at the horizont . No way .

Log periodic pointed at the zenith . No way .

Open vaweguide .Not bad 

Radar antenna at the horizont . No way .

Channel Master feeder for offset disches at the zenith . Good .

Channel Master feeder for offset disches at the zenith , Circolar polarization  : very good , the best  .

With cover to protect from moisture

Channel Master instruction for orthomode and circular polarization separation .

This one was the most effective solution .

I used a flange LNB with 10 GHz L.O. 

This cleared the first question : what is the downlink circular polarization Left Hand or Right Hand ? .

If I am well interpreting the Channel Master instruction it is : Right Hand Circular Polarization ( RHCP) .

The first question to be solved was : the nine beacon carriers was coming from a cluster of nine near satellite od only from one satellite ? 

This was cleared from using very narrow beam antennas , like the panel seen on the link or the 90 cm dish : 

https://air-radiorama.blogspot.com/2022/01/ricevere-i-beacon-delle-rete-starlink.html

And his image that gave ( like the dish ) the quick images of nine carriers at the same time . 

This means that the center carrier ir modulated with a senx/x pulse ( heart beat ) with a frequency that is the difference between the carriers .

Due to the doppler effect ( in this case around 1 kHz/s it is not easy to measure with precision this frequency ) .

I have done this demodulating some carrier beacons in AM , while passsing trough the maximun RF demodulated band of 192 KHz of HDSDR , like in teh following video .

In this case it is quite easy measure the carrier frequency of the modulation in the spectrum of the baseband , because this frequency will be steady ( in frequency , not in amplitude ) .

I have done this in the following two video , with a result near 44 kHz .

The mystery of the frequency around  60 KHz was after explained as an oversampling artifact .

The second armonic of 88 KHz , sampled at 96 KHz give an artifact at 104 KHz , that , beating with 44 KHz generate the carrier at 60 kHz .

I found that the frequency was very very near to 45/1024 MHz , as in the table ,with another measurements made from a very smart guy with name Oleg .

Ithink it it is not a case , but a very good sysyem to get clock sincronization .

To be continued .....