UHF-Satcom.com - Skynet 5A UHF/SHF monitoring Last update
14/01/2013 19:54:16 -0000
Jump to Skynet 5A
Skynet 5B Skynet 5C
Skynet 5D
 |
Skynet 5A is the first of the 'new generation' of
British Military satellites. It was launched on March 11, 2007 by Arianne-Space. Skynet 5A was initially placed at about 177W where it
underwent testing by the USAF Satellite Control Facility. It was then
relocated to its operational slot at 1W where it will be commanded by
RAF Oakhanger. S-Band TT&C has been observed
on 2227.500MHz. Skynet 5A has 9 UHF transponders and 15 SHF transponders
operating at X-Band. The X-Band signals wobble slightly, it is presumed
that this is due to the oscillator settling down, or thermal effects.
Its estimated that SN5A has about a 20dB horn antenna for Earth coverage
downlink on X-Band. It is also quite possible that there is a steer able
X-Band antenna of about 60cms to 1m diameter. The UHF helical antennas
are probably about 8 turns to give Earth coverage. There may also be Ka
band downlinks but this is yet to be confirmed. Wanted: Any
info on Skynet 5A - stuff like RF power output level, dish / antenna size / gains etc.
If you have any info, please send it to the contact addresses at the bottom of the homepage.
You can use the form here to anonymously
submit information.
Greetings to Paradigm-Logica and the MOD, frequent visitors to UHF-Satcom.com! |
UHF-SatCom frequencies (freqs xBr,pjm &
Maik)
S-Band TT&C frequencies.
|
Downlink Freq |
|
Notes |
Transponder spectrum plot |
|
2227.500 MHz |
|
Coherent TPX - carrier seen drifting in and out of lock. |
|
SHF-SatCom frequencies.
|
Downlink Freq |
Band Width |
Notes |
Transponder spectrum plot |
|
7261.000 |
22 MHz |
Active with a few PSK signals |
|
|
7287.750 |
22 MHz |
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7314.500 |
22 MHz |
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7340.250 |
20 MHz |
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7365.000 |
20 MHz |
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7401.000 |
36 MHz |
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7447.000 |
40 MHz |
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7494.000 MHz |
|
Tracking beacon or TT&C (+-20KHz data) - probably
QPSK |
 |
|
7494.045 MHz |
|
PSK with cyclic data, possible TT&C |
|
|
7488.000 |
34 MHz |
Regenerative beacon and tt&c etc |
|
|
7529.000 |
40 MHz |
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7577.000 |
40 MHz |
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|
7615.000 |
20 MHz |
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7640.000 |
20 MHz |
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7666.000 |
22 MHz |
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7689.000 |
22 MHz |
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7715.000 |
20 MHz |
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7740.000 |
20 MHz |
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Skynet 5B is the second of the 'new generation' of
British Military satellites. It was launched on November 14th, 2007 by Arianne-Space. Skynet 5B was initially placed at 6E where it
underwent in orbit testing. It was then
relocated to its operational slot at 53E where it will be commanded by
RAF Oakhanger. |
UHF-SatCom frequencies
S-Band TT&C frequencies.
|
Downlink Freq |
|
Notes |
Transponder spectrum plot |
|
2227.500 MHz |
|
Coherent TPX - carrier seen drifting in and out of lock. |
|
SHF-SatCom frequencies.
|
Downlink Freq |
Band Width |
Notes |
Transponder spectrum plot |
|
7261.000 |
22 MHz |
|
|
|
7287.750 |
22 MHz |
|
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7314.500 |
22 MHz |
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7340.250 |
20 MHz |
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|
7365.000 |
20 MHz |
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|
7401.000 |
36 MHz |
|
|
|
7447.000 |
40 MHz |
Single PSK cf=7427.5MHz |
|
|
7495.800 MHz |
|
Tracking beacon or TT&C (+-20KHz data) - probably
QPSK |
 |
|
7488.000 |
34 MHz |
|
|
|
7529.000 |
40 MHz |
|
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|
7577.000 |
40 MHz |
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7615.000 |
20 MHz |
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7640.000 |
20 MHz |
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|
7666.000 |
22 MHz |
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7689.000 |
22 MHz |
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7715.000 |
20 MHz |
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|
7740.000 |
20 MHz |
|
|
 |
Skynet 5C is the third of the
'new generation' of British Military communications satellites. It was
launched on June the 12th, 2008 by Arianne-Space from Kourou. Skynet
5C (#33055) is currently parked at its geostationary slot of 17.88
degrees West. Currently, the X-Band TT&C and S-Band beacons are active,
with X-Band transponder testing underway. The X-Band TT&C
beacon was activated around 11:30 BST on the 26th June 2008. |
UHF-SatCom frequencies
|
Downlink Freq |
Bandwidth |
Notes |
Transponder spectrum plot |
|
245.900
|
38KHz |
|
 |
|
249.500
|
8KHz |
|
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249.550
|
8KHz |
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249.880
|
8KHz |
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249.900
|
8KHz |
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250.100
|
8KHz |
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254.730
|
38KHz |
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256.5905
(Note: This tpx has moved to 256.600) |
38KHz |
|
 |
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261.100
|
38KHz |
|
 |
S-Band TT&C frequencies.
|
Downlink Freq |
|
Notes |
Beacon spectrum plot |
|
2252.486MHz |
|
|
|
SHF downlink frequencies (monitored off
air).
|
Downlink Freq |
Band Width |
Notes |
Downlink spectrum plot |
|
7249 to 7273 |
24MHz |
spot beam ? |
7261.000 tpx centre - not confirmed with tpx noise
tests
|
|
7275.75 to 7299.75 |
24MHz |
steerable beam ? |
7287.750 tpx centre |
|
7302.5 to 7326.5 |
24MHz |
steerable beam ? |
7314.500 tpx centre |
|
7328.25 to 7352.25 |
24MHz |
steerable beam ? |
7340.250 tpx centre |
|
7353 to 7377 |
24MHz |
steerable beam ? |
7365.000 tpx centre |
|
7378 to 7422 |
44MHz |
|
|
|
7425 to 7469 |
44MHz |
|
7447.000 tpx centre - not confirmed with tpx noise
tests
|
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7471 to 7505 From L to R:
7491.74904 PSK
7492.200 CW
7492.24404 PSK
7492.55904 PSK |
34MHz |
TT&C beacons 2 narrow band telemetry downlinks
running at 19.2Kbps BPSK / DSSS earth coverage horn or
low gain antenna |
 |
|
7505 to 7553 |
48MHz |
steerable beam ? |
7529.000 tpx centre |
|
7554 to 7600 |
48MHz |
|
|
|
7604 to 7628 |
24MHz |
spot beam ? |
7616.000 tpx centre |
|
7628 to 7652 |
24MHz |
|
7640.000 tpx centre - not confirmed with tpx noise
tests |
|
7655 to 7677 |
22MHz |
|
7666.000 tpx centre - not confirmed with tpx noise
tests |
|
7677 to 7701 |
24MHz |
|
7689.000 tpx centre - not confirmed with tpx noise
tests |
|
7703 to 7727 |
24MHz |
spot beam ? |
7715.000 tpx centre |
|
7728 to 7752 |
24MHz |
|
7740.000 tpx centre - not confirmed with tpx noise
tests |
The pictures above show two transponder moves during the commissioning of
Skynet 5C.
|
|
Skynet 5D is the forth and final of the
'new generation' of British Military communications satellites. It was
launched on the 19th December 2012 at 21:49 UTC by Arianne-Space from Kourou. Skynet
5D (#39034) is currently parked at its geostationary slot of 25
degrees East. Currently, UHF, X-Band transponders, X-Band TT&C and
S-Band beacons are active. The X-Band TT&C
beacon was activated around the 6th January 2013.. |
SHF downlink frequencies (monitored off
air).
|
Downlink Freq |
Band Width |
Notes |
Downlink spectrum plot |
|
7275.000 |
|
|
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|
7314.500 |
|
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7320.000 |
|
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7365.000 |
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7401.000 |
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7447.000 |
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From L to R:
7491.74904 PSK
7492.200 CW
7492.24404 PSK
7492.55904 PSK |
34MHz |
TT&C beacons 2 narrow band telemetry downlinks
running at 19.2Kbps BPSK / DSSS earth coverage horn or
low gain antenna |
 |
|
7529.000 |
|
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7550.000 |
|
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|
7589.500 |
|
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7730.000 |
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On the 8th January 2013, Skynet 5D UHF / X-Band tests were underway, with
a test of the onboard UHF receiver. The output of the onboard receiver was
looped to an X-Band downlink centred at 7314.500MHz, resulting in
approximately a 30MHz wide lump of RF being down linked. The FFT below shows
the 30MHz wide downlink - you can click on it for the full resolution
version. Signals included most of the Braziallian pirates, Sicral DAMA
uplinks, UHF air to air comms, including UAV coordination frequencies, Link
11 / TADIL comms, ATIS from Chang-Mai airport, Russian terrestrial phone
trunks, and hundreds more signals.
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