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Allen Telescope Array
Antennas from an ATA PerspectiveAntennas from an ATA Perspective
FASR Workshop FASR Workshop May 24, 2001May 24, 2001
David DeBoer, Project Engineer/Deputy Project Manager, SETI InstDavid DeBoer, Project Engineer/Deputy Project Manager, SETI Instituteitute
Allen Telescope Array
OutlineOutline
• ATA Overview• Antenna• Costing/timeline
Allen Telescope Array
ATA TeamATA Team• SETI Institute
– Rob Ackermann– Larry D’Addario– Mike Davis– Dave DeBoer– John Dreher– Gerry Harp– Girmay-Keleta
• RAL– Robert Abe– Leo Blitz– Douglas Bock– Geoff Bower– Calvin Chang– Matt Dexter– Greg Engargiola– Ed Fields– Matt Fleming– Doug Thornton– Lynn Urry– Jack Welch– Dan Werthimer– Mel Wright– Daning Zhou
• Other– Ed Ackermann– John Andersen– Charlie Cox– Niklas Wadefalk– Sandy Weinreb
Allen Telescope Array
The Allen Telescope ArrayThe Allen Telescope ArrayA Joint Project Between the SETI Institute and UCB/RALA Joint Project Between the SETI Institute and UCB/RAL
Hat Creek Radio ObservatoryHat Creek Radio ObservatoryCasselCassel, CA, CA
350 x 6.1 m350 x 6.1 m
Allen Telescope Array
Design Goals for the ATADesign Goals for the ATA
Allen Telescope Array
ATAATA
Near finalconfigurationof 350 antennas –surveying isunderway
Allen Telescope Array
ATA Signal PathATA Signal Path
Front EndAntenna RF to IFConverters
fA
fB
fC
fD
optical fibers
TunableLOs
IF Processor
IF: 1-2 GHz
back ends
IF Processor
IF Processor
IF Processor
digitize, track detect
back ends
back ends
back ends
from other antennasRF: 0.5-11.2 GHz
Allen Telescope Array ATA IF Processor Design ATA IF Processor Design →→Extremely Flexible InstrumentExtremely Flexible Instrument
3° FOV for array@ 1.2 GHz
Correlator images the entire FoV(50-400 MHz)
Beam formerBeam formergeneratesgenerates16 dual16 dual--polpolpencil beams pencil beams anywhereanywherein the skyin the sky(100 MHz)(100 MHz)
Arecibo•
Allen Telescope Array
Null FormationNull Formation
Original Beam
350 x 2 = 700 degrees of freedom
Allen Telescope Array
Ring BeamRing Beam
Allen Telescope Array
Complex Pattern Can Be Complex Pattern Can Be Written With NullsWritten With Nulls
Allen Telescope Array
RFIRFI
Allen Telescope Array
Solar “Mitigation”Solar “Mitigation”
Allen Telescope Array
New Wideband Feed DesignNew Wideband Feed Design
• Dual-pol, log-periodic
• Covers0.5–11.2 GHz
• 1.2 m long
• Metallic innerpyramid housesLNA and cryo
Allen Telescope Array
Cryogenics Inside FeedCryogenics Inside Feed
Dewar with LNA Inside Compressor
Focus Drive
Electronics Package
120 cm
Allen Telescope Array
F/O Link F/O Link –– Commercial Unit Commercial Unit
DiscoveryPhotodiode
FujitsuLaser/EA Modulator
RF Input Port BiasTee 1 km
SM fiber spool
Optical loss≅ 1.32dB
Ilaser= 60 mAPlaser= 5 mW
λlaser = 1556 nm
RF Output Port
BiasTee
Allen Telescope Array
ATA OptimizationATA Optimization
BW
TA syseff
/$/
max
~42 KLots of A Good eff
11 GHzCheap
Allen Telescope Array
Offset Gregorian design– confocal rotationally symmetric conic sections for no cross-
polarization (Tanaka/Mizusawa). Let
and
wheref focal distanceD primary diameterθH semi-flare angleyc primary/secondary
separation
=
2tan2 H
Df θξ
DfDyc
//
=ζ
Allen Telescope Array
Offset GregorianOffset Gregorian
Allen Telescope Array
PatternsPatterns
Allen Telescope Array
FoundationFoundation
Allen Telescope Array
PedestalPedestal
Allen Telescope Array
AlidadeAlidade
Allen Telescope Array
Antenna ControlAntenna Control
Allen Telescope Array
Low Cost AntennasLow Cost Antennas
• Three bids– Orbitron– Vertex/RSI– Andersen Manufacturing
Allen Telescope Array
Andersen MfgAndersen Mfg
Allen Telescope Array
Primary SurfacePrimary Surface
#7#7
0.0270.027" RMS" RMS
Additional money Additional money from JPL to from JPL to
improveimprove
Allen Telescope Array
Electronics and PowerElectronics and Power--law law Sets SizeSets Size
Cos t for Array w ith 1 M$ Electronics
5.00
5.50
6.00
6.50
7.00
7.50
8.00
8.50
9.00
9.50
0.00 0.50 1.00 1.50 2.00 2.50
log( e le me nt diame te r )
log(
cos
t in
dolla
rs )
log(Acost)log(Ecost)log(totalcost)
25 m
Cost for Array with 10 K$ Electronics
4.00
4.50
5.00
5.50
6.00
6.50
7.00
7.50
8.00
8.50
0.00 1.00 2.00 3.00
log( element diameter )
log(Acost)log(Ecost)log(totalcost)
5m
Allen Telescope Array
Current Model (JWD)Current Model (JWD)Cos t per Hectare
0.00
5.00
10.00
15.00
20.00
25.00
30.00
4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0
Primary Diame te r (m)
M$
LaborDS PRF/IFTre nchF/O LinkFront EndAnte nna
6.1 m
Allen Telescope Array
Timeline for ATATimeline for ATA
20022002• CDR• Build Production Test Array (PTA)
– Foundations next week– Pedestals in mid-July– Antennas by October (room temperature feed)– Cryogenic feed by December
• Operational tests begin• Develop tools/infrastructure
Allen Telescope Array
Timeline for ATATimeline for ATA
• Begin construction• First use of partial array
• Array complete - extensions begin• Feed into SKA technology decision point
20032003--20042004
20052005
Allen Telescope Array
ThanksThanks
• ATA Intranet site– Send me an e-mail at [email protected]
• www.seti.org• astro.berkeley.edu/ral
