Another analysis to TURKSAT3U beacon.

Another analysis to Turksat3u, from the first day recorded beacon.
In my previous posts I pointed to the overlapping of Turksat's beacon with other signal !
and the source possibility of this signal considered as a failed RS-40 satellite beacon !!!.
Today while I was cleaning the hard disc from  large I/Q files,
I replay the TurkSat3U's  I/Q file which was recorded on April 26, 2013

Another frequency spectrum analysis shows these features: !

1- The second signal started and stopped with Turksat3u beacon at the same time .
2- A mirror image to some letters, with similarity in the duration and its numbers.
    see photo for letters A and N.
3- The other signal was stronger than the Turksat's beacon signal.
4- Both signals had the same amount of fading, this was so obvious before the end of transmission.
    and this was clear too at the audio spectrum shot below !
     More features to be followed, after more analysis.

For sure the above hypothesis accepted other explanation !
But I'm personally convenes to a certain degree that  the 2nd signal source was the Turksat3u itself !!

There are certainly more questions than answers about what happened to Turksat3u!!?
And what was the cause of the abrupt silence ?

Signal at 437.200Mhz

 20.38  20:51 UTC 2nd  May

For the 2nd time a signal notice during TurkSat3 pass at 437.200Mhz

The signal was disappeared  with satellite LOS!!!.

It looks like some kind of digital Mod!!!.
I'll monitoring this frequency .  

TurkSat3U status

Beacon Status:
Nothing copied since last Friday 26 April.!!

A weak continuous signal (carrier?) with slight Doppler was noticed during the last pass 19:28 19:40 UTC This signal came around the TCA and disappeared around the LOS. Not exactly at the down-link frequency but around  +/- 437.200 MHz.
Yes many sky junks around ! , which can be the cause of such a QRM, It may be interesting to monitor this frequency as long as the signal disappeared with the TurkSat3U's LOS.

Another event occurred last Friday, April 26, 2013, 10:39 AM, while I was monitoring Turksat3U I've noticed two CW signals overlap each other!!, The 1st signal was a clear TurkSat3U Beacon; the other signal was an ambiguous CW signal !.You can see the audio analysis at the previous post ..
Mike(DK3WN)  identified the source of the other signal as a failed CW beacon of RS-40.
(Thanks Mike for help)

Transponder status:
Loop test performed several time ,but nothing heard or seen on the waterfall.

At my previous post Mr.Ahmet Sofyalı from  Space Systems Design and Testing Laboratuary of ITU. Had posted a comment stated:
Since Friday (April 26th), TURKSAT 3USAT could not be heard again.
Thanks Mr.Sofyalı for visiting and comment .
Unfortunately this record from Friday, April 26, 2013, 10:39:51 AM
Still we are QRV with great hope.

Most updated info for Turksat 3U available at Facebook !?
Tamsat Amsat-Tr   and   Turksat3usat Fan Club

TURKSAT3U CW BEACON

TURKSAT3U CW BEACON

Turksat 3Usat cw beacon heard over Africa

A weak turksat beacon heard - low pass elevation 
Xponder not heard - !!!
Cubebug-1 beacon not heard !!!

Congratulation to all team for successful launch and orbiting  

At the 1st pass I  detect the beacon too at the  I&Q audio  record file ! 
RTL-SDR confused me with it low resolution  . again congratulation

Upcoming Satellites Frequency Chart

Upcoming Satellites Frequency Chart
All Satellites Frequency List Update see JE9PEL HP

Nanosatellite linear transponder (3) TurkSat

TurkSat is a 3U CubeSat, the first communication nanosatellite mission of ITU (Istanbul Technical University),

The VHF/UHF transponder is the main payload to provide two -way radio communications. The VHF uplink has a frequency of 145.990 MHz, the UHF downlink band has a frequency of 435.200 – 435.250 MHz. The transponder consists of amplifiers, filters, mixers and AGC (Automatic Gain Control) stages. The VHF uplink signal is up-converted to the UHF downlink signal linearly. The system has again of 150 dB with 60 dB of the total gain being adjustable. The communication system with transponder has a link margin of 10 dB.

Uplink center frequency	145.965 MHz
Downlink center frequency	435.225 MHz
Bandwidth	±25 kHz
Output power	30 dBm (1W)
Receive sensitivity, gain	-120 dBm, 150 dB
Total power consumption	< 3 W
Automatic gain control	Yes
Antennas	Monopole (Cu-Be)
PCB (Printed Circuit Board) size	8.8 cm x 8.8 cm x 0.5 cm
Transponder mass	< 250 g
Supply voltage	2.8 V, 3.3 V, 5 V DC
Microcontroller	MSP430F5438

 Specification of the transponder system

 Illustration of the transponder desktop model (image credit: ITU)

Antenna system: The communication system consists of three subsystems with their backups: the modem, transponder, and the beacon.

System	UHF Antenna (435 MHz)	VHF Antenna (145 MHz)	No of antennas
Transponder	2	2	4
Modem	2	2	4
Beacon	2	-	2
Total	6	4	10

Antenna system of the satellite communication subsystem

Source eoPortal