UHF-Satcom.com - Sicral UHF/SHF/EHF monitoring                                                                             Last update 10/11/2009 11:56:53 -0000

Update 18/05/2009 - Sicral 1B is on station at 13 East, transmitting on UHF, X and Ka band (see tables below for frequency info)

Update 24/11/2006 - Sicral 1A has returned operation on UHF. This occurred sometime in the morning of today. The UHF transponders are looped through at X-band, but no other user traffic has been seen on X-band.

Update 10/11/2006 - Sicral 1A signals vanished from the slot at 16.2 east! No signals have been detected on either UHF or X-band. The S-band TT&C was located.


Sicral-1A is located at 16 degrees East - it's the first Italian satellite developed for defence telecommunications. It's primary users are the Italian navy who make extensive use of the UHF and SHF transponders. This satellite is interesting as it has UHF to SHF cross strapped transponders, which is looped at SHF on the ground, and re-transmitted back down to Earth at UHF. The effect of this is that the delay through the satellite appears to be twice what is expected.

Sicral-1B is located at 13 degrees East. It has UHF, SHF and EHF downlinks, details of which are in the table below.

Don't forget to check the Sound Samples page for audio from Sicral.

Sicral 1A downlink frequencies

Downlink Freq  Notes Transponder spectrum plot
252.200MHz-252.350MHz Cross strapped with 7393.200MHz-7393.350MHz

UHF uplink + 7100MHz = SHF downlink

258.150MHz-258.300MHz 258.200MHz IDR TBD
267.100MHz-267.250MHz New TPX!! Cross strapped with 7408.100MHz-7408.250MHz

UHF uplink + 7100MHz = SHF downlink

2203.4470MHz S-Band TTC  
7500.000MHz TT&C Beacon www.uhf-satcom.com
7393.275MHz Relay of UHF 252.275 transponder, looped back up on X, down on UHF. The SICRAL satellite can operate simultaneously on several frequency bands (SHF, EHF and UHF), a characteristics first in Europe, with the possibility to switch the bands on-board of the satellite (first in the world). The UHF satellite repeater is the Europe’s most powerful and the only one to operate inter-connected to the SHF / EHF band.

To the right is the spectrum plot, the thin line on the left is a squeaky wheel up linked via UHF, to the right is the Italian Navy Stanag 4285 traffic / voice traffic.

7408.200MHz NEW UHF TPX 03/09/2006

UHF uplink is retransmitted down from Sicral on 7408.200MHz, looped at the ground station, and retransmitted up to Sicral. It is then transmitted back down on 267.200MHz UHF.

Simplex FM comms and data bursts heard on the X-band downlink, wrapped to a very strong downlink on UHF.

20250.000MHz TT&C beacon  
20437.000MHz carrier  
20988.000MHz carrier  
21028.650MHz PSK  
21031.500MHz PSK  
21044.750MHz PSK  
21052.800MHz PSK 3MHz wide  
21093.275MHz Downlink from 293.275MHz uplink confirmed!! 20800MHz + UHF uplink
21108.175MHz Downlink from 308.175MHz uplink confirmed!! 20800MHz + UHF uplink

Sicral 1B downlink frequencies

Downlink Freq Notes Transponder spectrum plot
252.400 30 KHz wide 'bent pipe' TPX  
252.450 30 KHz wide 'bent pipe' TPX  
252.500 30 KHz wide 'bent pipe' TPX  
252.550 30 KHz wide 'bent pipe' TPX  
259.975 30 KHz wide 'bent pipe' TPX  
260.025 30 KHz wide 'bent pipe' TPX  
260.075 30 KHz wide 'bent pipe' TPX  
260.125 30 KHz wide 'bent pipe' TPX  
267.875 30 KHz wide 'bent pipe' TPX  
267.925 30 KHz wide 'bent pipe' TPX  
268.000 30 KHz wide 'bent pipe' TPX  
268.050 30 KHz wide 'bent pipe' TPX  
268.100 30 KHz wide 'bent pipe' TPX  
22xx.xxxMHz S-Band TTC  
7261.250 to 7316.750  
7390.75 to 7416.250 7413.60 to 7416.10
7432.500MHz 22MHz 7421.5 to 7443.5 7426.05 to 7435.42
7353.750 to 7586.250  
7647.000MHz 33MHz 7632 to 7665  
7656.250MHz   7638.87 to 7653.23
7405.000MHz Beacon / TTC same as 20250

(1MHz bandwidth FFT  ---->)

20250.000MHz Beacon / TTC same as 7405

(1MHz bandwidth FFT  ---->)

20644.250MHz Strong carrier with sidebands Possible TPX limits = 20637.5MHz to 20700MHz
20649.250MHz Strong carrier with sidebands  
20654.250MHz Strong carrier with sidebands  
20659.250MHz Strong carrier with sidebands  
20664.250MHz Strong carrier with sidebands  
20666.250MHz Strong carrier with sidebands

(2MHz bandwidth FFT  ---->)


20668.750MHz Strong carrier with sidebands

(2MHz bandwidth FFT  ---->)

TPX testing with signals +50dB over noise seen!!

20671.250MHz Strong carrier with sidebands

(2MHz bandwidth FFT  ---->)

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