ARGOS

Double - Heterodyne - FFT - Radio - Spectrometer

RAPPETH Zürich

Minikolloquium June 11th 2002Michael Arnold / Christian Monstein

Astronomical Receiver Gathers Outer Space (Tyler Brulée)

Directory• Specifications (required / measured) • Instrument comparison• Open day application 15.06.2002• Usage sites• Focal plane unit• Double heterodyne receiver• Frequency diagram• Backend hardware• Backend software• Backend realtime aspects• Backend dataflow• First results• Team members• Development time, costs• Summary• ARGOS related URL`s

SpecificationsParameter Required Measured• Frequency range 1415 ± 25 MHz 1415 ± 125 MHz• Bandwidth > 50 MHz 250 MHz• Polarization 1 linear vertical• Spectra/sec >= 100 10...15• Integration (TD, FD) ‚must‘ ‚in progress‘• Channels or bins > 32 up to 50`000 tested• Offseterror vs temp. nil < 0.03 dB/K• Offseterror vs ac-power nil < 10 µdB/Vac• Gainerror vs temp. nil < 0.03 dB/K• Gainerror vs ac-power nil < 10 µdB/Vac• Frequency error nil < 160 ppm / < 5ppm• Timing error < 50 msec/day TBD• Power consumption nil 191W (RX only)• Sensitivity < 5 sfu 800/300 Jansky rms• System temp. < 2 dB (175K) 530/250 Kelvin• Dynamic broadband nil > 40 dB• Dynamic FFT > 24 dB ~ 50 dB• Liftime > 5 year TBD

Instrument comparisonParameter ARGOS PHOENIX-2 CALLISTO

Receivertype FFT Frequency agile Frequency agileFrequency range 1290-1570 MHz 100-4000 MHz 47-862 MHzObs.-bandwidth 250 MHz 3900 MHz 815 MHzResolution (FD) 250 MHz {i} 1, 3, 10 MHz 110 KHz (65 KHz)Resolution (TD) > 66 msec 500 µs...1sec {i} 2 msec...10 sec {i}Polarization linear (vertical) L, R, I, V linearSampletime/pixel 2 nsec 0.5 msec 2 msec (TBD)Channels 1... {ii} 1...2000 1...12500System temp. 250/530 K {iii} TBD {iii} TBD {iii}RMS noise 300/800 Jansky TBD {iii} TBD {iii}Dynamic range ~ 50 dB > 40 dB > 40 dB

{i} depending on number of channels {ii} not yet checked; tested until 50'000{iii} with/without calibration unit

Open day application 15.06.2002

Receiver1415 MHz±125 MHz

Impedance matching 75/50

DC-decoupling

Possible sources:

• Solar radio noise between 11,70 GHz and 12,75 GHz• Satellite signals (downlinks)• Methanol CH3OH @ 12,178 GHz ± doppler shift• Cherenkow radiation from moon due to impact of TeV cosmic particles

IF=1578 MHz

SAT-receiver + power supply LNC

Usage sites

5m antenna Zürich 1 GHz-2.6 GHz (system tests only) 5m antenna Bleien 300 MHz - 3 GHz + 80 cm-SAT 10 GHz - 12 GHz

7m antenna Bleien 100 MHz - 4 GHz Option: Gorner Grat with 3m Cassegrain 210 - 820 GHz

Focal plane unit

PIN-switch #1

PIN-switch #2

Preamplifier, 1-4 GHzNF 0.9dB, G +35 dB

-3 dBNoise Source +35 dB ENR

Input fromantennafeed

Ta/Cali

+28V

To/Texc

+15V/0,3A

Output to receiver

Termination 50 @ To=300K

J1.0

J2.0J1.1=PD3

J2.2=PD2

J1.2=PD4

J2.1=PD1

+5V/-12V

Double heterodyne receiver

X X+26dB +15dB +41dB

local oscillator-110,000GHz

+13dBm

local oscillator-28,710GHz+13dBm

Power-divider

Reference clock 10MHz+6dBm ± 3dBm

Pow

er-

divi

der

Logarithmicdetector

25mV/dB

analog-digital-converter 8bit

500Ms/secPC

-1.7dB

100µAVideo

LowpassfilterDC-250MHz

1. mixer 2. mixer

LSB-bandpassfilter8,585GHz ± 125MHz

-3dB-3dB

Radio - Telescope1290 - 1540 MHz

isolator isolator

isol

ator

isol

ator

equalizer-amplifier

1. IF-amplifier 2. IF-

amplifier

IF2=IF1-FloIF1=Fsy-FrfFrf=Fsy-IF2-FloIF2=Fsy-Flo-Frf

Coaxialcable ~60m-9dB ...-35dB

Frequency diagram

F1h=8,710GHz

F1z=8,585GHz

F1l=8,460GHz

Fh=1,540 GHz

Fl=1,290 GHz

Power

Frequency

1. mixer stage

F2h = 250 MHzF2l = 0.0 GHz = dc

2. LocaloscillatorLO2 = 8,710 GHz

Power

Frequency

2. mixer stageSelection withlowpassfilter

F1 = LO1 ± Frf = 8,585 GHz ± 125 MHz

F2 = F1 - LO2 = 125 MHz ± 125 MHz

Upper sideband USBwill not be used

Selection of lowersideband LSB bybandpassfilter

Frf =1,415 GHz

1. LocaloscillatorLO1 = 10,000 GHz

PC Hardware:Pentium III 800 MHz (Win98)

384 MByte RAM

~40 GByte HD

Acqiris Digitizer

500 Msamples/sec

2 Msamples on-board memory

8bit Resolution

50 input impedance

LabView Driver

Backend hardware

Backend software

• 50`000 lines/spectrum (=5KHz)

• Spectral integration down to 500 lines/spectrum

• Sampletime 2ns (500MHz)

• 100s per data array (one line of spectrum)

• Fastest Win98 timeslice 1ms needs fast integration

• Bottle neck disc I/O and integration process in time

Backend realtime aspects

Fileserver

pisces.ethz.ch

hercules.ethz.ch

Webserver

ARGOS Receiver

/ftp/pub/hedc/fs/data1/rag/observations/argos

/argos/ plutos.ethz.ch

Argos Controller

D:/data/*.raw

Overview

ftp via php

ftp.php

Backend dataflow

First results

Simulation of RADAR-pulses(top) and a small bandwidth,drifting signal to checkcross-modulation sensitivityof the preamplifier in the focal plane unit.Here, rf-power is to high thus ‚ghosts‘ apear parallel to signal.

Testband Frequencyrange max Power

ERMES-pager 168-172 MHz < -23 dBmTelepager 400-430 MHz < - 36 dBmCitizenband 900-1350 MHz < - 24 dBmRADAR 1300-1350 MHz < -64 dBmNATEL D/GSM 1710-1855 MHz < -23 dBm max. power is 5µW (16mV @ 50)

Sun-transit seen with ARGOS & PHOENIX-2

FFT-spectrometerBW=spacing=500KHz

Frequency agile spectrometerBW=10MHz, spacing=30MHz

No background subtraction applied...

ARGOS PHOENIX-2

Team members

Defending NF-budget & requirements Arnold BenzMechanical design & manufacturing Frieder AebersoldSoftware design, integration & test Michael ArnoldPostprocessing Peter MessmerManufacturing of focal plane unit Andreas JamesManufacturing ARGOS-receiver Roland MoserManufacturing FOPA-controller Roland MoserConceptual & hardware design Christian Monstein

Development time, costs

Hardware design+manufacturing 1.4 year with 10% = 280hSoftware design 1.3 year with 10% = 260hSystem integration 0.2 year with 20% = 80hSystem tests 0.5 year with 25% = 250hTotal 870h

Material costs SFr. 67`000

Summary

• A cheap instrument compared to PHOENIX-2, AOS• Portable (more or less)• Flexibel in terms of bandwidth resp. number of channels• Observation of molecule lines possible• Experience with LabView in real time environment• Curious about scientific results• Observation of solar radio noise in Ku-band on June 15th

ARGOS related URL`s

• Status ARGOS http://pisces.ethz.ch/argos/index.php

• More Infos http://www.astro.phys.ethz.ch/rapp/

ETHAstronomical InstituteChristian MonsteinScheuchzerstrasse 7CH-8092 Zürichmonstein@astro.phys.ethz.ch