Hundred tenth edition of the N&O column / Spooks newsletter

(Date: Fri Nov 3, 2006 2:19 pm (PST))

Space communcations < 500 MHz

Heard in October:

VO-52	:	145.920 MHz	with SSTV signals
MilSatCom	:	252.125 MHz	USAF Raven 52 and Raven 53
MilSatCom	:	261.575 MHz
MilSatCom	:	262.125 MHz	USAF Spear## call
Formosat 3B	:	150.012 & 400.032 MHz	Doppler beacon
Formosat 3C	:	150.012 & 400.032 MHz	Doppler beacon
Formosat 3D	:	150.012 & 400.032 MHz	Doppler beacon
Formosat 3E	:	150.012 & 400.032 MHz	Doppler beacon
Formosat 3F	:	150.012 & 400.032 MHz	Doppler beacon
Cosmos 2378	:	149.940 MHz	Mode: RTTY
Cosmos 2398	:	149.910 MHz	Mode: RTTY
Cosmos 2386	:	149.940 MHz	Mode: RTTY
Cosmos 2407	:	149.970 MHz	Mode: RTTY
Cosmos 2414	:	149.970 MHz	Mode: RTTY
Gonets D1-3	:	264.9000 MHz	2400bd PSK data bursts
Gonets D1-5	:	264.4000 MHz	2400bd PSK data bursts
Gonets D1-7	:	264.7875 MHz	2400bd PSK data bursts
Gonets D1-9	:	264.7875 + 262.9125 MHz	2400bd PSK data bursts

All operational ORBCOMM satellites were heard on the following frequencies:
137.2000, 137.2250, 137.2500, 137.2875, 137.3125, 137.3975, 137.4400, 137.4600, 137.6625, 137.6275, 137.6875, 137.7075, 137.7125, 137.7375, 137.8000 MHz.
Mode: 4800bd SDQPSK. Doppler beacon on 400.0940 MHz.

NOAA 9	:	137.5000 MHz	Deactivated but has a sporadic carrier on 137.500 MHz.
NOAA 12	:	137.5000 MHz	Mode: APT
NOAA 15	:	137.5000 MHz	Mode: APT
NOAA 17	:	137.6200 MHz	Mode: APT
NOAA 18	:	137.9125 MHz	Mode: APT
METOP	:	137.1000 MHz	Mode: LRPT

The brand new ESA METOP satellite is monitored and controlled via the EUMETSAT Polar System (EPS) in Darmstad. It transmits on a number of frequencies. One of them is 137.1 MHz. This is the reason why NOAA 18 switched to 137.9125 MHz.

So far there are no decoders for non-pros, as far as I know. The weather pics are transmitter in LPRT (Low-Resolution Picture Transmission) which is not the same as APT that NOAA uses.

Frequencies:

LRPT 137.1 MHz. Mode: 72 kbps QPSK
AHRPT 1701.3 MHz. Mode: 3.5 Mbps QPSK
X-band 70 Mbps, only over Svalbard (Norway)
Telemetry 2230 MHz. Mode: 4096 bps CCSDS, SP-L/PSK/PM

ESA describes the transmissions as follows.

"Science data transmission to ground is ensured by three links:

An X-band link to the CDA station at Svalbard (N) to dump the SSR global data and for further forwarding via terrestrial transmission links to the EPS Central Site in Darmstadt (D).

The HRPT and LRPT providing continuous data transmission to ground in VHF and L-bands for local users. On-board encryption of the LRPT and HRPT data prevents access by un-authorised users. The encryption keys are generated in the EPS Key Management Centre and distributed via secure terrestriallinks to registered local mission users.

The HRPT service operates with a microwave link at L-band and broadcasts the full data content as recorded on board MetOp at 3.5 Mbps. The service is very similar to the existing service from the NOAA Polar Operational Environmental Satellites (POES) satellites and enables regional meteorological organisations to receive all relevant data in their area in real time.

The digital LRPT service at VHF provides a subset of the HRPT data. It is comparable to the existing Automated Picture Transmission (APT) analogue service of the NOAA POES satellites. APT has, as a main objective, inexpensive access of low resolution Advanced Very High Resolution Radiometer (AVHRR) instrument images by local users; in America it is very popular in schools. MetOp augments the service by an innovative on-board compression scheme that allows LRPT transmission of AVHRR data at full instrument spatial and radiometric instead of providing low resolution images."

Source:
European Space Agency http://www.esa.int/esaLP/ESAWK1094UCLPmetop0.html