GBT-related topics and information

New Cafeteria menu (Nov 2009)

Table of contents

Phase monitor systems
Traditional holography systems
Traditional holography papers
OOF Holography papers
Satellite tracking info
Photogrammetry systems
Main Az/El Servo
Links to laser range-finding references
Links to manufacturer's hardware datasheets
Loral and RSI technical memos
Active surface
Nearby webcams: Hot Springs, VA   Hillsboro, WV   Mt. Crawford, VA   Dolly Sods Wilderness, WV
Charleston: Tower     bridge

Recent URSI meeting proceedings

January 2008

pointers to GBT drawings

index: 121000
wheel crown: 121035
surface panel layout: 120520
subreflector: assembly=120700, spine tuss=120710, interface=120701, panels=120730

holography receiver: 35205 (block diagram=k003, IF=k002, MUX=k001)

Feed horn measurements

Existing phase monitor systems:

ATCA memo: atmospheric phase monitor system (30 GHz beacon, 1.75m dishes) preprint   newsletter
BIMA memo: atmospheric phase monitor system (broadband 12 GHz DBS=direct broadcast satellite)
LANL Space & Atmospheric Science Group: Shao, Carlos & Kirkland 1997 (IEEE link to Kirkland et al.) San Pedro River Riparian National Conservation area
LMT "Radio Seeing Monitor Interferometer", (Hiriart et al. 2002), 11.715 GHz
NRAO paper: NRAO site test interferometer (Radford et al. 1996) 11.7269 GHz, GStar4 at 105deg West
SMA memos: The SAO Phase Monitor (Masson et al. 1990), 11.712 GHz (GStar A2), 100m baseline, 1.8m antennas, 50%-ile excess path = 60um; some analysis given in Jason Stevens' memo at JACH

Existing traditional holography software:

CLIC: AIV manual: Using_CLIC by R. Lucas (part of Gildas) official CLIC manual at ESO
holo by T.K. Sridharan
JCMT software by J. Richer

Existing traditional holography systems:

Algonquin 45.7m: IEEE Transactions on Antennas and Propagation, Vol 52, Page 20, Jan 2004 (H2O masers)
* Baars et al. A&A paper
* ground-based beacon 3mm = 104.02 GHz, elev=8.3
* 1.2-hour maps, 180 rows, 37 returns to the boresite, spec=10um, goal=5um =measurement accuracies
* planning for Holography at the OSF
* Vertex: 264 panels in 8 rings (from APEX paper and on ADS)
* Alcatel: 120 panels

ATCA (maps=85x85): Optus-B3 beacon (30 GHz system built by Astrowave Pty Ltd in 2002), also a 12GHz system (rx by George Graves, backend by Astrowave), current summary
CSO (84 panels): FTS (shearing-interferometer) observations of planets; the new DSOS thermal active surface system
DSN 34m antennas: "Evolution of the Deep Space Network 34-M Diameter Antennas" by Imbriale (1998);   "Microwave Antenna Holography" by Rochblatt & Seidel (1992);   "Effects of Measurement Errors on Microwave Antenna Holography" by Rochblatt & Rahmat-Samii (1991);   "Microwave holography of large reflector antennas - Simulation algorithms" by Rahmat-Samii (1985);
GBT: GBT Memo 101 (S.D. White, Feb 1993)   GBT Memo 68 by Maddalena, Norrod & White
Haystack 37m (maps=256x256): Alan Roger's IEEE paper   12 GHz satellite (two pseudo-noise channels of BW 0.5 MHz each)
Effelsberg 100m: 1999 campaign (ITALSAT F1 and F2);   2001 campaign (EutelSat W2)
HartRAO 26m: Holographic Measurement of the 26m HartRAO Telescope by Benjamin Klein
HHT (60 panels): 2000 run   37 GHz Navy satellite LES-9 (probably a beacon)
IRAM 30m: 27 July 1996 newsletter article (39 GHz beacon from ITALSET, maps=128x128), also phase retrieval method at 86 GHz by Morris et al. 1988, also water maser holography with a 32x32 map in 20hrs and a 1.75m reference antenna
JCMT (276 panels with 3 motors each): ADASS proceedings (94 GHz ground-based beacon)
LMT: initial plans   Surface segments First results (July 2008)
Nobeyama 45m: Deguchi et al. 1993 paper in IEICE Trans. Commun.   Ukita & Tsuboi 1994 IEEE (ADS)
NRAO 12m: 12m Memo 174 (Craig Moore); 12m Memo 202 (L. D'addario, Nov. 1982)
OVRO: Dave Woody's SPIE paper (local PDF)
Parkes 64m: (maps=129x129, 129sec/scan) website (Intelsat VII at 3.95 GHz, Optus B3 at 12.75 GHz)
PdBI: ?
SMA: (72 panels in 4 rings = 8 across the aperture, maps=96x96, 3200x3200 arcsec = 33x33 arcsec) website and links (232.4 GHz ground-based beacon)
SRT: (Sardinia Radio Telescope, 64m under construction)
VLA (172 panels): "Microwave Holography for Antenna Metrology" by M. Kesteven (1994)   VLA test memo 169: VLA Holography (Kesteven 1993)
VLBA: VLBA holography system (2002) (GE4 beacon at 12.198 GHz)

"Traditional" Holography papers:

NRAO 12m: Surface Measurements of the NRAO 12M Antenna by A.N. Lasenby (ADS link), ESO-IRAM-Onsala Workshop on (Sub)Millimeter Astronomy, Aspenas, Sweden, June 17-20, 1985
ALMA 12m: Baars et al. 2007, "Near-Field Radio Holography of Large Reflector Antennas", IEEE Antennas and Propagation Magazine, in press
ATA 6m: Harp et al. 2011, "Primary Beam and Dish Surface Characterization at the Allen Telescope Array by Radio Holography", IEEE TAP, 59, 2004
Chilbolton 25m: Godwin et al. 1981, reference antenna = 2.4m, used OTS-2 satellite
HHT: Baars et al. 1999, "The Heinrich Hertz Telescope and the Submillimeter Telescope Observatory", PASP, 111, 627
Jodrell Bank: Padin, Davis & Lasenby (1987) (PDF)
5km telescope: Scott & Ryle (1977)
Medicina 32m: (11GHz phase retrieval, 240 panels, map=63x63) Tarchi & Comoretto (1993)
Noto 32m: (11.5GHz traditional) Tuccari et al. 2001, Phase reference holography of the Noto 32m VLBI antenna in Electronics Letters Online
KOSMA 3m: Fuhr et al. (1993)
IRAM 30m, 22GHz: Morris et al. (1988)
Effelsberg 100m: inner 80m=1492 panels, total=2356; mapsize=195x195, elevation scans (time<12hrs), 2.4m reference antenna, satellite=OTS-2@11.786GHz Grahl, Godwin & Schoessow (1986); phase retrieval results by Reich & Furst 1999 using ITALSAT F1 & F2 at 18.685 GHz, EUTELSAT at 11.698 GHz
Bennett et al. (1976) Microwave Holographic Metrology of Large Reflector Antennas
G.C. James (1993) Panel Setting from Microwave Holography by the Method of Successive Projections

Related papers

Y. Censor (2005) Computational acceleration of projection algorithms for the linear best approximation problem
Ohtera and Ujite (1975) Nomographs for Phase Centers of Conical Corrugated and TE11 Mode Horns

"Out-of-focus" holography papers:

General paper (including JCMT results): Nikolic, Hills, et al. 2007
GBT paper: Nikolic, Prestage, et al. 2007
Morris 1985: Phase Retrieval in the Radio Holography of Reflector Antennas and Radiotelescopes in IEEE Trans on Antennas and Propagation
Morris, Davis, Mayer 1991: Experimental assessment of phase retrieval holography of radiotelescope
Misell 1973: A method for the solution of the phase problem in electron microscopy
Dean et al. 2006: "Phase Retrieval Algorithm for JWST Flight and Testbed Telescope" ADS abstract, local PDF
SEST: (176 panels in 6 rings) Phase Retrieval Holography and Surface Adjustment of SEST Using the LES-8 Satellite (Whyborn & Morris)

Other methods:

NRAO 11m: (three-wheeled cart) Payne, Hollis & Findlay
IRAM 30m: Moon scans by Greve et al. (1998)
Salomonovich (1967): Measurements of Lunar Radio Brightness Distribution and Certain Properties of Its Surface Layer
Krotikov & Troitskii (1964): Radio Emission and Nature of the Moon
12-meter lunar images at 90 GHz
CSO lunar images at 850 GHz
GBT Memo 52: Azimuth and Parallactic Angle Tracking Near the Zenith (w/formulae)

Finding Available Satellites:

Original GBT holography used GSTAR IV: This satellite was built by GE Astrospace (now Lockheed Martin) and was launched on 1990/11/20. It operated at West Long 125 from 1990-1992, and was then moved to 105 degrees West. Beginning in 2002, it operated in inclined orbit. It was retired as of 2004/02/11 and is now drifting, last seen near Australia (April 10, 2007).

Telstar 5 was also observed during one session, and is still in service at 97.0 W longitude. For awhile it was called Intelsat Americas 5 (IA-5) with C-band and Ku-band, but now it is called Galaxy 25 or G-25 (NORAD ID = 24812). The Ku-band downlink is 11.7 to 12.2 GHz, linear polarization (H or V). Here is a spectrum analyzer shot of the 12.198 GHz beacon. In this plot, its beacon appears to be 15 dB above the noise floor.

Another option Galaxy 28 = G-28 (formerly called IA-8) at 89 West which appears to have 3 or 4 beacons from 11.19 to above 12 GHz. It is their newest and most powerful satellite (NORAD ID=28702). Here are spectrum analyzer shots for horizontal and vertical polarizations. Here is Galaxy-26 horizontal and vertical.

For a lower elevation source, there is Echostar 5 launched in 1999 at (azim=241, elev=23) from Green Bank. (NORAD ID=25913).

To calculate satellite positions using Norad two-line orbital elements (TLE), one can use the linux GUI program Gpredict, or some roll-your-own C++ code called SxP4. For either case, the orbital elements are available to registered users of or CelesTrack. Satellite orbital elements change daily due to drifts and orbital thruster usage. The orbital inclination causes a diurnal north-south motion and the orbital eccentricity causes a diurnal east-west motion, resulting in a roughly elliptical path. In order to get gpredict to compile on Linux Fedora Core 4, I had to install (or upgrade) to the following packages via their source code: glib-2.12.11, atk-1.18.0, cairo-1.4.2. Then 'setenv PKG_CONFIG_PATH $HOME/usr/local/lib/pkgconfig' and continue building pango-1.14.10. Then 'setenv LD_LIBRARY_PATH /usr/local/lib' and continue building gtk+-2.10.0, then curl-7.16.1. Finally, build gpredict-0.7.1. SxP4 is far simpler in its requirements.
Example of satellites with interesting motion: Sirius 1: 26390, Sirius 2 (GE-1E): 25049, Sirius 3: 25492, plot

Intelsat has an eleven-element ephemeris format described by Robert Wolf in section 4.4.4 on pages 68-69 (pages 84-85 in the PDF) in a 210-page paper called "Satellite Orbit and Ephemeris Determination using Inter Satellite Links"

Digital TV standard protocols DVB-S protocol (converts signal to white noise prior to transmission) example spectrum functional block diagram
Intelsat Satellite coverage maps including IA-8 at longitude 89 West with 52.8dBW EIRP in Ka band and 47.9dBW in Ku band digital TV signals useful for broadband (400MHz) holography
Lyngsat satellite information page DISH network on EchoStar 8/10 at 110 deg West longitude at 12.2 GHz
NASA satellite tracker J-Track 3-D database of 300 satellites
PanAmSat recently acquired by Intelsat
SatcoSX including AMC5 at 79 West (42dBW EIRP); AMC9 (46dBW EIRP)

Components and datasheets for a broadband system:

R. Kimberk's schematic for the new Mauna Kea phase monitor

Analog Devices AD8347 0.8 GHz to 2.7 GHz Direct Conversion Quadrature Demodulator (with evaluation board available) local PDF
Invacom QPH 031 Quad polar LNB ($69) no external reference; hacked with an 11.25 GHz external LO by R. Kimberk; stable to < 0.1 degrees rms on minute time scale
VSAT PLL LNB SPV-55SM, 65SM, 75SM with external reference flange mount, no horn
Mini-circuits ZX60-2522M amplifier (500-2500 MHz) 20dB, max voltage = 7V, operating current=86mA
Multiplier comparison: Gilbert cell vs. diode Heterodyne spectrometers with very wide bandwidths (Andy Harris 2002, SPIE)
Comparison of Analog Continuum Correlators (Koistinen et al. 2002, IEEE)
Merrimac Industries Intro to I & Q modulators (10MHz to 8GHz)
SPC Electronics Corp. LNB (Low Noise Blockdown Converter) for Ku-Band

Advantanges of a broadband system over a beacon
1. Total power from beacons are weaker: 1-20 dBW EIRP (equivalent isotropic radiated power) rather than 40-50 dBW in the datastream. (Not intended to be picked up by the consumer, some are used for tracking by the service provider. Some are modulated and used for communications.) For comparison, the total power in the SMA 232 GHz beacon on Subaru is about 100nW. If it was isotropic and placed at geostationary altitude (35786km), it would then be 36237km distance from SMA antennas (rather than 200m) and would need to be 3.28 kW = 35 dBW EIRP to provide an equivalent signal (ignoring atmospheric attenuation). In fact, the FWHM of the beacon horn is 9 degree at 232 GHz, which is a gain of 364 = 25.6dB. Thus the EIRP would need to be 60 dBW!
2. Beacon system requires a narrow passband filter (of order 5kHz). For example, the satellite used by the SAO phase monitor drifted out every 30 minutes and computer had to reacquire it via GPIB bus.
3. Beacon system requires downconversion stage from the LNB output (~1 GHz) down to vector voltmeter range (often 500MHz or less). Also, the passband filter is easier to implement at lower frequencies, such as 21 MHz.
4. Beacon system has multiple reflections/standing waves. The broadband system will help wash those out. They manifest themselves in the data as follows: 1) in total power focus scans of the subreflector, one sees oscillations rather than a smooth peak. 2) in the aperture domain, one sees broad radial oscillations (2 or 3 across the dish) in the aperture phase which flip up/down after the subreflector is moved and a new map is made.

Issues Common to Both Systems:
1. The satellites "move" diurnally by 0.02 degrees or so (stationkeeping).

Photogrammetry systems

VLA: VLA test memo 220 (Butler et al. 1999)
Arecibo: NAIC Newsletter from March 2001   CMSC Conference paper, August 2001 (Edmundson & Baker)
APEX: reached 35-40 microns rms with photogrammetry newsletter
SPT: reached 100 microns rms with photogrammetry after first attempt
Hobart 26m: 2005 paper in The Photogrammetric Record v. 20, page 205, local PDF (reached 65um rms on a 26m telescope: 1/400000)
KOSMA: 2003 SPIE paper claims 10 micron measurement accuracy on a 3m dish, but achieved surface rms only 35 microns rms; poster paper
ODIN: reflectors aligned via photogrammetry to accuracy of 50 microns


Wyler Zeromatic inclinometers (AG gas-damped capacitive readout)

Servo components

Manufacturer Product documentation usage
Baldor Sweodrive Model 90 motor amplifier (PDUs) bandwidth limited at 50 Hz motor amplifiers on Az/El drives
BEI Industrial Encoders L696SSE-1 custom-built 22-bit azimuth and elevation encoders azimuth: serial# 920404 (July 1992), elevation: 920426 (June 1992) BEI reports: Aug 2000, Feb 2002 Feb 2002
FAG bearings (northern Bavaria) D83722 bearing, AAA-BBB mfg code 7A elevation bearing
GE Fanuc Embedded Systems VMIVME 4116 8-Channel 16-bit Resolution Analog Output Board local PDFs: datasheet   manual current request from acu to rate boards
VME-2528 128-bit TTL Digital Input/Output Board
GE Fanuc / VMIC VMIC 3118 16-bit, 32 channel ADC VME converter module servo feedback
Koyo Electronics Industries, Co., Ltd. Direct Logic 205 Modular Programmable Logic Controller (PLC) specs GBT limit switches, etc.
Limitorque Corp. 1.0HP stow pin motor
Lohmann Stolterfoht elevation motor gearbox
Motorola MVME 167-32A crate controller (SBC transition module 5E = MVME712M5E) local PDFs: programmer's reference acu running VXWorks
Precision Control Devices (PCD) subcontractor of Loral subcontracted to Ben Parvin and Wodek Gawronski at JPL original servo design
Reliance SXT blower Dutymaster 2.2 Amp, 240V, 3450 RPM, 3/4 HP az and el motors
Symmetricom VME time and frequency processor local PDFs: manual   acu time
Miscellaneous Past attempts at command shaping GBT Memo 203 by D. Wells Posicast

Servo miscellany

DC brush motors: 16 x 30HP on azim, 8 x 40HP on elev, max rated RPM = 1035 (but we run them at 1750 in elev to get 20 deg/min) max slew rates: azim = 40deg/min = 0.667 deg/sec, elev = 20deg/min = 0.33 deg/sec (for comparison, VLBA=90deg/min in az, and 30deg/min in el)
max acceleration: 0.10 deg/sec/sec (in practice, 0.05)
position loop 3dB BW = 0.3Hz in azim, 0.29Hz in elev
velocity loop 3dB BW = 5.7Hz in azim, 4.1Hz in elev
range of motion: +/-270deg azim, 5-95 elev
turret speed: 1 RPM
DC brushless motors: prime focus and subreflector motors
AC motors: PF boom and turrent pin
subreflector range: +/- 1.5deg = +/- 14 arcmin on sky
subreflector velocity = 1 deg/sec = 9 arcmin/sec
subreflector acceleration = 1 deg/sec/sec = 9 arcmin/sec/sec
survival stow: elevation = 66 degrees, and 90 degrees to the wind concrete access azimuths: 84.50, 91.75, 174.50, 181.75, 264.50, 271.75, 354.50, 361.75
elevation name
5.131 snow dump
60.105 survival
65.864 bird bath
77.850 access

Spare channel layout:
1 Azimuth current command
2 Azimuth rate command
3 Azimuth rate feedback
4 Elevation current command
5 Elevation rate command
6 Elevation rate feedback
7 Azimuth current feed forward
8 Elevation current feed forward
9 Truck 4 Wheel 13 Pot
10 Truck 4 Wheel 13 LVDT
11 Truck 4 Wheel 13 Fixed Pot
12 -
13 Channel 15 acc @ el axle
14 Channel 16 acc @ el axle
15 -
16 -

Hardware data sheets

Manufacturer Part number Datasheet Usage
Acces I/O Products, Inc. PCI-DIO Series 48S Digital Input/Output Card local wiki PDFs: datasheet, manual new holography backend interface (with change of state interrupts)
Agilent HP54503A Digital Oscilloscope, 500MHz, 1GSa/s, 2ch
33120A Function / Arbitrary Waveform Generator, 15MHz (discontinued) local PDF datasheet lab
Acam-Messelectronic GmbH TDC-GPX multifunctional High-end Time-to-Digital converter
(8 channels at resolution 81ps up to 2 channels with 10ps resolution)
local PDF datasheet
Advanced Microwave Labs AMF-1902 ferrite circulator GBT holography IF box
Alimak Hek Champion US Series elevators US-2000R Little Champ (lower elevator) US3300 (upper elevator)
Analog Devices AD9858 1 GSPS Direct Digital Synthesizer local PDF datasheet
ADuC834 microconverter chip local PDF datasheet GDAQ for accelerometers
Dependence of intertial measurements of distance on accelerometer noise Thong et al. 2002
OP07 ultralow offset voltage operational amplifier local PDF QD illuminator circuit
OP400 Quad low-offset, low-power op amp local PDF accelerometer circuit
OP497 Precision picoampere input current quad operational amplifier local PDF QD heater box
AD824 Single supply, rail-to-rail low power, FET-input op amp local PDF QD detector preamplifier circuit
AD586 high precision 5V reference local PDF QD heater box
AD790 Fast, precision comparator local PDF QD heater box
TMP01 lower power, programmable temperature controller local PDF QD heater box
Andrew Corporation FSJ1-50A, HELIAX superflexible foam coaxial cable corrugated copper, 1/4 inch diameter local datasheet
FSJ2-50A HELIAX Coax, 3/8" diameter, 0.5-13400 MHz local PDF GBT holography reference receiver connection
FSJ4-75A HELIAX superflexible foam coaxcial cable corrugated copper, 1/2 inch diameter local datasheet
Anzac TV-50 Iso-T GBT holography IF box
Burr-Brown UAF42 Universal Active Filter (SOL 16-pin package) local PDFs: datasheet   Filter design program QD GDAQ
SHC5320KH High-speed, bipolar monolithic sample/hold amplifier GBT holography system
PCM78 16-bit audio analog-to-digital converter GBT holography system
SDM854BG (obsolete) GBT holography system
Celestron CGE Computerized mount (item 91524) with 1.5 arcmin accuracy idea to locate and image the retroflectors with a CCD camera
Cougar A2P2520 amplifier 100-2500 MHz 36dB gain, 3.5dB noise figure GBT holography IF box
Crydom Solid state relays (panel mount) local PDF QD heater box
Dallas Semiconductor (see Maxim)
DataTaker DT 50 series 3 local PDFs: datasheet   SRD-99 data recorder   User's manual used with pyrgeometer and QD
DeLogger 4 software local PDFs: specifications used with pyrgeometer
Fairchild Semiconductor MM74HC393 Dual 4-Bit Binary Counter local PDF QD illuminator circuit
Faro Laser Tracker X V2 (Absolute distance measurement) local PDF datasheet azimuth track refurbishment tool
Laser Tracker Xi V2 (Absolute distance measurement and interferometer) local PDF datasheet
FLIR Systems ThermaCAM Researcher Professional software imaging software used in IR thermography experiments
FXR/Microlab HW-15N Bias Monitor Tee local PDF GBT holography system
Greenray Industries YH-522-45 oscillator 100MHz local wiki PDF GBT holography reference
HP Pavilion a6120n PC gondor & edoras
HP8494B Manual Step Attenuator (0-11dB) local wiki datasheet lab usage
Inframetrics (merged with Agema and FLIR) 160x120 8-12 micron uncooled microbolometer camera 0.1C resolution rented for 2 weeks
Kipp & Zonen CG3 pyrgeometer (4.5 to 42 microns, 150deg FOV, 10k thermistor YSI44031 (PDF)), 7.86E-06 V/(W/m^2) newer model with shade = CGR3
Linear Technology LTC1966 Precision micropower Delta-Sigma RMS-to-DC Converter local PDF QD detector circuit
LT-1021 precision reference local PDF Accelerometer circuit
Luxeon DS46 local PDFs: datasheet   design guide QD illuminator circuit
Mathworks list of PTCS Matlab licenses
Maxim DS32kHz 32.768kHz TCXO (temperature compensated crystal oscillator) local PDF QD illuminator circuit
MAX038 High-frequency waveform generator (obsolete) local PDFs: datasheet   evaluation kit QD illuminator circuit
MAX663 Dual Mode 5V/Programmable Micropower Voltage Regulators local PDF QD detector circuit
MAX8215 Dedicated microprocessor voltage monitor local PDF QD DT-50
Max 7662 accelerometer circuit
Meade LX200R with 1 arcmin precision to locate and image the retroflectors with a CCD camera
LX90GPS with 3 arcmin precision to locate and image the retroflectors with a CCD camera
Melles-Griot 02 CCG 003 Solid Glass Refroreflector; dia. = 25mm one per panel
Microline 4012-10 GBT holography IF box
Mini-circuits ZFL-500LN amplifier local PDF specs laser ranger
ZFDC10-5 directional coupler PDF GBT holography IF box
SLP-150 low-pass filter (DC to 140 MHz) GBT holography IF box
ZFSC-3-1 power splitter local PDF specs laser ranger
ZFSC-2-1 power splitter GBT holography system
ZFL-1000 local wiki PDF GBT holography system
Miteq XT0-05-100J-15P oscillator (100MHz, 0.01ppm, +15V) local PDF datasheet laser ranger
Narda Microwave 30503 10dB coupler lab usage
National Instruments PXI-1010 PXI Chassis with Integrated SCXI-8PXI/4SCXI Slots local PDF datasheet laser ranger
PXI-6289 18-bit, 500ks/s (multichannel), 625 ks/s (1-channel), 32 analog inputs local PDF datasheeet laser ranger
National Semiconductor LM1875 20W audio power amplifier local PDF QD illuminator circuit
LM79XX Series 3-Terminal Negative Regulators local PDF QD illuminator circuit
LM340/LM78XX Series 3-Terminal positive regulator local PDF QD illuminator circuit
LM117 3-terminal adjustable regulator local PDF QD heater box
LM78L05 3 Terminal Positive Regulator accelerometer circuit
Newman Tools Pro-3600 digital protractor
Norsat Intl. 1009X Ku-band LNB with external reference ($530) local wiki PDF GBT holography system
Omega Bolt-On Washer Thermocouple Assemblies local PDF QD DT-50
Omni-Spectra 20186 WR90 x SMA(f) adapter GBT holography system
Onset HOBO pro series temperature logger BoxCar software lab usage
On-Trak Photonics PSM2-10 (10mm square) Position sensing detector local PDF QD detector
Opto22 Solid-state power relays QD heater box
Panasonic Multilayer Ceramic chip capacitors (Array type) Series ECJ local PDF   Size 11 type 0603 and size 12 type 0805 QD detector preamp circuit
LC-R061R3PU sealed lead acid battery (discontinued) local PDF QD DT-50
Pellissier H5 Hydrostatic Level SLAC paper
Power-one Linear power supplies local PDF QD heater box
Q-bit QBH-9-812 amplifier GBT holography system
QBH-9-816 amplifier GBT holography system
Reactel 5B2-450-6 S11 tubular filter (5-section, bandpass, CF=450MHz, BW=6MHz) PDF GBT holography IF box
SBIG Astronomical Instruments all-sky optical camera local PDF datasheet possibly useful for GBT
Scitec HAC STC-7002 telephone manual telephone in CV office
Sercalo SL2x2-9n-12-15 fast (5msec), latching MEMS fiber switch local PDF datasheet laser ranger
Setra Model 270 Barometric Medium Pressure local PDF datasheet
Silicon Designs Model 1221J-002 Low noise analog accelerometer (2 Volts/g) local PDF presently in use at GBT
Model 2412-005 Open Frame Triaxial Accelerometer (+/-5G) local PDF possible future use? (although they don't seem to offer the +/-2G version in this package)
Spectrum Control Inc. Resin sealed bolt-in filters local PDF QD heater box
Spectrum Microwave MDR 6100 Dieletric Resonator Oscillator (DRO) local wiki PDF GBT holography system
Susumu thin film chip resistors (RR1220 series) local PDF QD detector preamp circuit
Telonic Berkeley Inc. TLP150-3BA1 tubular low pass filter, 1/2 inch diameter GBT holography system
Thor Labs LDC205 Laser Diode Current Controller local PDF manual laser ranger
Texas Instruments SN5407 Hex buffers/drivers with open-collector high-voltage outputs local PDF QD heater box
INA126 Micropower Instrumentation Amplifier Single and Dual Versions local PDF accelerometer X-axis signal conditioning circuit
3M 929 Series Boardmount Socket straight solder tails (0.1 inch) local PDF (#929647-09-36-ND for header, 929850-01-36-ND for socket) QD GDAQ
WJ Communications WJ-M8THC mixer (1MHz-3.4GHz input) obsolete Holography system
YSI (sold to Measurement Specialties Inc.) YSI083 attachable surface temperature probe, 0.01 C resolution, 8-sec time constant may have been replaced with glass-encapsulated devices? structural temperature sensors
YSI4800LC thermistor linearizing circuit structural temperature sensors

Laser range finding references

Abshire & Gardner (1985) Atmospheric Refractivity Corrections in Satellite Laser Ranging
Amann et al. (2001) "Laser ranging: a critical review of usual techniques for distance measurement"
Dandliker, Salvade & Zimmermann (1998) Distance measurement by multiple-wavelength interferometry
Dandliker et al. (1995) High-accuracy distance measurements with multiple-wavelength interferometry
Dandliker, Thalmann & Prongue (1988) Two-wavelength laser interferometry using superheterodyne detection
de Groot (2000) Unusual techniques for absolute distance measurement
Estler, Edmundson, Peggs & Parker (2002) CIRP Annals Laser Metrology -- An Update
Estler (1985) High-accuracy displacement interferometery in air
Gelmini, Minoni & Docchio (1994) Tunable, double-wavelength heterodyne detection interferometer for absolute-distance measurements
Hashemi, Hurst & Oliver (1994) Sources of error in a laser rangefinder
Jain (2003) A survey of Laser Range Finding
Marini & Murry (1973) Correction of Laser Range Tracking Data for Atmospheric Refraction at Elevations Above 10 Degrees
Mendes & Pavlis (2004) "High-accuracy zenith delay prediction at optical wavelengths"
Payne (1973) An Optical Distance Measuring Instrument
Poujouly & Journet (2002) A twofold modulation frequency laser range finder
van Brug & Klaver (1998) On the effective wavelength in two-wavelength interferometry
List of publications on corner cube polarization properties

PTCS references

Liebe & Hopponen (1977) Variability of EHF Air Refractivity with Respect to Temperature, Pressure, and Frequency
Wells (2000) GBT Active Optics Systems and Techniques in ADASS IX, ASP Conference Series 216, 355
Calibration and modeling of a dual-axis inclinometer (Parker, Schwab, Shelton, Weadon 2005)
TM14: Azimuth Encoder Drive Analysis (1992-03-27)
TM19: Equations of Motion of Subreflector Positioner
TM41: Elevation Encoder Drive Analysis (1992-08-18)
TM42: Elevation Encoder Backshaft and Spider Beam Design Analysis (1992-07-01)
TM47: Surface Accuracy (rev. 3) (2000-01-24)
TM49: Locked Rotor Frequency (Norrod) (1992-09-22)
TM52: Pointing Accuracy (rev. 3) by D.M. Kelley (1993-12-11)
TM 101: Reflector Panels -- Design and Analysis (1992-12)

Tipping radiometer references

Radiometrics MP-Series Microwave Profilers
Deriving the tropospheric integrated water vapor from tipping curve-derived opacity near 22 GHz Deuber et al. 2005 (ADS link)
A new 22-GHz radiometer for middle atmospheric water vapor profile measurements Deuber et al. 2004
Microwave Radiometer for Cloud Carthography: A 22-channel ground-based microwave radiometer for atmospheric research Crewell et al. 2001


GBT temperature sensor photos by Jason Ray
Optical camera mount view1 from alidade walkway
view1 from alidade walkway (with arrow)
view2 from alidade walkway
view from standing on the dish
Measurements of holography reference horn location (2003) explanation 01
Right-side laser platform View 1 of laser ranger platform about 1/4 of the way up the feedarm
View 2 of laser ranger platform about 1/4 of the way up the feedarm
Feed arm sideview from ground (portrait)
Feed arm sideview from ground (landscape)
Feed arm rearview from ground
Closeup of laser platform from behind on the ground
Feed arm tip sideview from ground
Panel-setting tool Panel setting tool
Adjustment Dial

Active Surface

Fuses Meng & Sloot 1995 paper on fuses
IOP these are numbered from 0..7
Lucas Schaevitz 1100 HR-2890 series LVDT there are 16 channels per LVDT module, LVDTs are numbered from 1..69 PDFdatasheet (photo)
Other LVDTs tested: Transcoil 210A-0300, RDP Electrosense, Schlumberger, Kavlico, Pickering
Actuators there are 2209 of them
Mitutoyo 534-182-1 digimatic dial indicator used on the panel setting jig