Transcript Document 7603376

VHF SATELLITES
Gregor Požar, S53RA
Whitton Amateur Radio Group, London
16. March 2007
VHF SATELLITES
- definition by S53RA :-) satellites that can be heard on VHF
- not about amateur satellites, neither about military sats in 200-400 MHz band
- almost all in Low Earth Orbit (LEO)
- 400-3000 km, usually abt. 800-900 km above ground
above: GEO satellite
left: LEO satellites
TOOLS:
- FM and SSB VHF (136-180 MHz) receiver
- PC with soundcard, audio cable
- Software (free downloadable): satellite tracking, spectrogram,...
- satellite tracking - SatScape (G4ILO)
- frequency vs time graphs („waterfall“) - SpectrumLab (DL4YHF)
- weather image decoding - WXtoIMG weather images
SIGNALS:
- non-modulated carriers (beacons)
- some kind of telemetry
- navigational data
- WX APT images
- power from miliwatts to a couple of watts.
Satellite tracking software - SatScape screenshot
Time
Audio spectrum analyzer software – Spectrum Lab screenshot
time vs frequency diagram (SSB mode)
Doppler Shift – satellite signal easily recognizable, heard as a falling
tone or viewed as (a section of) the Doppler curve (+-3kHz on VHF).
Most satellites can be received
with fairly simple equipment
Example of a station setup in a
hotel in Central London
My equipment:
- Yaesu FT-100d
- Kenwood TH-28
- Laptop with Satscape and
SpectrumLab Software
- Hand-held VHF antenna on a
window
NOAA Weather Satellites
- National Oceanic & Atmospheric Administration
- polar satellites (inclination near 90 deg.)
- a flypast takes abt. 15 minutes
- transmiting on SHF (1,6 GHz) and also on VHF
- VHF 137 MHz FM APT WX image and beacon/telemetry data
- similar to SSTV, scanning line after line, continous transmission, 5W
- transmits two channels (two pictures), visible light and infrared
- bandwidth 36 kHz – not suitable for commercial HAM receivers
- dedicated receivers, top-line scanners (AoR5000), home-made receiver
- with limitations a HAM FM radio can be used to some point
NOAA 12
NOAA 14
NOAA 15
NOAA 16
NOAA 17
NOAA 18
–
–
–
–
–
–
137,500 APT,
APT N/A,
137,500 APT,
APT N/A,
137,620 APT,
137,910 APT,
- WXtoIMG software (free)
136,770 beacon/telemetry
137,770 beacon/telemetry
137,350 beacon/telemetry
137,770 beacon/telemetry
137,350 beacon/telemetry
137,350 beacon/telemetry
Improvised setup - Kenwood TH-28e and a 2m GP antenna
Example of a received WX image
- visible light channel
- some noise – fading (GP antenna)
- cca. 15 minutes
Both channels displayed
- channel A (left) - visible light
- channel B (right) infrared
- bandwidth limitations
NOAA beacon/telemetry
- heard on 136,770; 137,350; 137,770 MHz
- either non-modulated carrier or telemetry
(+-8kHz, 8320bps, PSK Split-Phase, TIP-Tiros Information Processor)
- power 0,5 or 1 W
OTHER WEATHER SATELLITES ON VHF
- METOP-A, a new European WX LEO satellite
- Similar in function to the NOAA satellites, more sophisticated
- Launched in autumn 2006
- Reported healthy on all systems
- Should be transmitting on VHF also (137,100 MHz)
- Russian Meteor, Okean, Resurs and similar (137 MHz)
- None heard, probably malfunctioning or dead
- Chinese Feng-Yun
- Feng-Yun 1C* and 1D heard at 180,006 and 180,007 MHz – carrier only
FengYun 1C*
* destroyed Jan 2007
180,006 MHz
FengYun 1D 180,007 MHz
ORBCOMM
- short messages relaying system
- „M2M“ applications (machine-to-machine)
- channels on 137-138 MHz
- constellation of cca. 36 satellites
- strong signal, 20W SD-PSK user signal at 4800 bit/s
- 5W „Gateway Transmitter“, O-QPSK at 57,6 kbps, 137,56 MHz
- non-modulated beacon on 400,1 MHz
- in the past interfered with NOAA satellites transmissions
- telemetry can be decoded
above: Orbcomm, 400.1 MHz
right: Orbcomm, 137 MHz
NNSS (Navy Navigational Satellite System)
- first trials in 1964
- initially for military use only,
later available for civilian use also
- satellites known also as TRANSIT or OSCAR
(not to be confused with HAM OSCAR sats)
- last launches in spring and summer 1988
- discontinued for navigation at the end of 1996
- now used as NIMS – Navy Ionospheric Monitoring System
- characteristic multi-tone audio
NNS O-23 & O-25
149,988 MHz and 399,968 MHz
NNS O-31 & O-32
149,978 MHz and 399,942 MHz
- example of FM demodulation spectrogram
- components at 2200-2400 and 4500-4700 kHz (and higher)
- melodic multi-tone audio, little known about data format and encoding
- power 0,75 – 1 W
Special place in history – Transit 5B-5 (NNS O-2)
- launched 15 december 1964
- useless due to malfunctioning two weeks after launch, but continued to
transmit
- probably the oldest satellite still transmitting
- 136,650 MHz
- signal sounds similar to other NNS sats (but at “twice” the speed
and components at 5,4 kHz and just under 10 kHz)
- or simple carrier only
- or a typical unstable signal
- this probably depends on whether satellite has enough power (sunlit, etc...)
Transit 5b5 – NNS O-2 spectrogram examples – SSB spectrogram
above: unstable signal
right: 5.4 kHz
signal
Transit 5b5 – NNS O-2 spectrogram examples
FM spectrogram
5.4 kHz
10 kHz
Russian LEO navigational satellites – COSMOS-PARUS
- two sub-systems, Nadezhda (civil, no longer active) and Parus (military)
- Parus - 6 orbital planes 30 deg. apart, usualy one active satellite per
orbital plane
- easy to detect, strong signals (1W)
- RTTY, 50bit/s - 3 kHz and 5 kHz (plus 7kHz time reference signal)
- signal contains standard Moscow time information and satellite positions
- frequencies 149.910, 149.940, 149.970 and 150.030 MHz)
- new satellites, e.g. Cosmos 2414 january 2005
Cosmos 2398 (149,910 MHz and 399,760 MHz)
Cosmos 2378 (149,940 MHz and 399,840 MHz)
Cosmos 2407 (149,970 MHz and 399,920 MHz)
Cosmos 2414 (149,970 MHz and 399,920 MHz)
COSMOS – PARUS, FM signal
- 3 and 5 kHz RTTY components (50 bit/s)
- 7 kHz attenuated by receiver filters and barely visible
COSMOS – PARUS, SSB signal examples
left: 3 and 5 kHz components
below: 7 kHz time reference
right: UHF signal
SATELLITE BEACONS AT 150,0125 MHz
- quite a few satellites are carrying a beacon on this frequency,
some more to be launched in the near future (NPSAT, STPSAT1,
C/NOFS,...).
- usually also a beacon at 400,032 MHz (and some in L-band also)
- Main use of the beacons are ionospheric measurements (similar to
the ex-navigation NIMS sats) – by measuring the delay in VHF and
UHF signal arrival various parameters of the ionosphere can be
estimated (e.g. TEC – total electron content, ionospheric
tomography, etc.)
SATELLITE BEACONS AT 150,0125 MHz
- GEOSAT (GEOdetic SATellite), U.S. Navy sat, main equipment is radar
altimeter for precision measurement of sea waves height)
- GFO - GEOSAT FOLLOW-ON,
similar to GEOSAT in purpose
- RADCAL, used as a target for C-band radars calibration, GPS attitude
demonstrator, UHF store-and-forward
- SIX „FORMOSAT 3“ series satellites (3A,3B,3C,3D,3E,3F), joint USATaiwan project, known also as „COSMIC“ (Constellation Observing
System for Meteorology, Ionosphere and Climate), same spacecraft type
as the Orbcomm ones.
SATELLITE BEACONS AT 150,0125 MHz
GEOSAT, 150.0125 MHz
RADCAL, 150.0125 MHz
GFO, 150.0125 MHz
SATELLITE BEACONS AT 150,0125 MHz
FORMOSAT 3D, 3E, 3B - „formation flight“
At the beginning all three sats (flying
relatively close together) have the same
speed relative to the receiver. As the
satellites are approaching us, their speed
difference relative to the receiver increases
(due to different spatial position of each
satellite) and the traces „spread“. While
flying away, the opposite happens and at the
end the traces merge into a single one.
OTHER SATELLITES IN THE 136-138 MHz BAND
- some older „survived“ sats
Tiros-N (137.500 MHz and 137.770 MHz)
Tiros-10 (136.233 MHz)
Nimbus-4 (136.500 MHz)
Tiros-10
Solrad 7B (136.800 MHz)
Tiros-N
Isis-1 (136.410 MHz)
EGRS-13 / Secor-13 (136.800 MHz)
Timation-2 (137.380 MHz)
Isis-1
EGRS-13
ERS-15 (136.400 MHz)
Poppy 6 (137.410 MHz) and Poppy 7 (137.080 MHz)
Shinsei (136.695 MHz)
Eutelsat 1-F4 (137.142 MHz)
Solrad-7B
Nimbus-4
Shinsei
Mimosa
Poppy
Compass-2
- some newer also: Mimosa (137.140MHz), Compass-2 (137.350MHz),
Hamsat VO-52 (137.150 MHz, 137.200 MHz, 137.225 MHz)
- usually some kind of telemetry, unstable signal or non-modulated carrier
- there are some other reported (ERS-20, etc.) but I was not able
to hear them.
OTHER SATELLITES IN THE 136-138 MHz BAND
Old weather satellites (Tiros 10, Tiros N)
Tiros-N, 137,770 MHz
Tiros-10, 136,233 MHz
1,3 kHz AM
Tiros-N, 137,500 MHz
OTHER SATELLITES IN THE 136-138 MHz BAND
Old weather satellites (Nimbus-4, 136.500 MHz)
left: Nimbus-4, 4000bps PCM/PM VIP
(Versatile Information Processor) data.
right: Nimbus-4, unstable signal,
sometimes fluctuating at random,
sometimes a stable carrier...
OTHER SATELLITES IN THE 136-138 MHz BAND
a few other examples:
ERS-15
SOLRAD 7B
SOLRAD 7B,
unstable attitude
OTHER SATELLITES IN THE 136-138 MHz BAND
above: MIMOSA (and VO-52)
above: Compass-2
left: HamSat (VO-52)
PASSIVE SATELLITE REFLECTIONS
NAVSPASUR RADAR
- U.S. Navy satellite - tracking radar
- continous non-modulated TX, separate TX-RX sites
- 3 TX sites: Gila River 216.970MHz
Jordan Lake 216.990 MHz
Lake Kickapoo 216.980 MHz (the strongest)
- 3,2 km linear array – 2556 dipoles, each has 300W amp
- 767kW input power and 40dB antenna gain -> 6,3 GW ERP
- fence-shaped antenna pattern
- moonbounce reflection with RX dipole in USA
- moon and sat reflections can be observed in Europe
GRAVES, 143.050 MHz
- active since 2006
- similar in purpose to NAVSPASUR
- but less powerful (heights up to 1000 km)
- ERP several megawatts
- located in France, TX (central France) - RX (south France) cca 300 km
THANK YOU!
SOME USEFUL LINKS
http://fpp.hamradio.si/s53ra/xhamradio/hamsatvar1.html
http://www.uhf-satcom.com
http://mdkenny.customer.netspace.net.au/emitters.html
http://www.zarya.info
http://www.svengrahn.pp.se
http://space.skyrocket.de
http://home.arcor.de/satellitenwelt
http://www.itr-datanet.com/~pe1itr/
http://www.heavens-above.com
http://nssdc.gsfc.nasa.gov/nmc/sc-query.html
http://centaur.sstl.co.uk/sshp
http://www.hearsat.org
Satscape: www.satscape.co.uk
DL4YHF Spectrum Lab: http://people.freenet.de/dl4yhf/spectra1.html