AO19 phased array feed
apr 2013
Topics
Pre installation:
Sources
History of what we did
Results
Misc:
- x101/ao19/ .. has memos notes from prior to aug13
observation.
- x101/projects/ao19/ copied by
projects/byu/..
- has byuazza, and some idl code.
- /share/obs4/usr/x101/src/*ao19* .. has command files
and program logs.
- /share/olcor/corfile.xxx has interim cor data
when connected to ao port. also has time, az,za for some
patterns when byu system connected.
- log files for byuazza.log was in /tmp/byuazza.log on
megs3.. but it got rebooted before i moved the file so we lost
this.
Pre installation:
Sources: (top)
Strong lband calibration sources available:
- catalog codes:
- N nvss.
- flux is at 1400 MHz,
- coordinates are J2000
- maj,min are major minor axis in asecs
- C
- ao calibrator file .
- flux is at 1600 MHz
- The source name links are nvss images of the source at 1405
MHz.
- The images are +/- 7.5 amin, ra increases to left , dec
increases up
Source
|
Cat
|
Flux Jy
|
Notes
|
|
|
1400
|
1665
|
|
point
src calibrators
|
J0108+133
|
N
|
12.05
|
10.31
|
maj,min :18.1,<16.2 ..
chris say 4' size?
|
J0137+331 (3C48)
|
C
|
15.77
|
13.67
|
This transits @noon around
19apr10. freq @ 1665
|
J0318+164 (CTA21)
|
C |
7.85
|
7.17
|
|
J0437+296(3C123) |
N |
54.9 |
|
maj,min 27.7,<18 |
J0502+252
|
N |
5.7
|
|
maj,min , 15.4,<18.5
|
J0521+166 (3C138)
|
C |
9.22
|
8.27
|
8% polarized @ 1665
|
J1229+020 (3C273) |
N
|
54
|
|
maj,min 21.5,<15.9
|
J1331+305 (3C286)
|
C |
14.55
|
13.32
|
9% polarized @1600MHz.
|
J1330+251
(3C287)
|
N |
6.93
|
6.26
|
maj,min < 16.0 <
15.55
|
J1347+122 |
N |
5.41
|
5.02
|
maj,min <18.2 < 17.1
|
J2014+23
(3C409) |
N
|
|
11.23
|
maj,min 21,<14.8 (at
1665MHz via chris salter).
|
J2123+250
(3C433)
|
N
|
10.27
|
|
maj,min 19,<13.9 (chris
says 2')
|
J2232+117
|
N
|
7.2
|
|
maj,min <19,<17
|
J2253+161
(3C454.3) |
C |
13.16
|
13.34
|
This is a variable. Strength
probably different. |
extended
sources
|
J0534+22(crab)
|
N
|
324
|
|
maj,min 127,127
053428.03 +2202 02.5
|
M87
(.25 deg) image
M87 (.25 deg) contour map: (.ps)
(.pdf)
123049.46 122321.6
|
N |
138
|
|
maj,min 48.4 18.7
|
J1648+0504 (3C348) Hercules A
|
|
47
|
|
at least a double... 16 51 11.70 +04 59 19.0 23Jy 16 51 3.85 +04 59 41.9 11.1 Jy 16 51 4.94 +04 59 42.3 8.5 Jy
|
192342.51 143031.1
(W51
image .5 deg square)
W51 contour map (.ps)
(.pdf)
|
N |
36.8
|
|
maj,min 83.9,63.7
|
B2018+295 (3C410)
|
C |
8.65
|
|
size:41 arc secs
|
B2121+248 (3C433)
|
C |
10.63
|
|
size 120 arc secs
|
|
|
|
|
|
J1538+147 (.ps)
(.pdf)
contour map
|
N
|
.012
|
|
12 mJy (peak) nvss source .
40 sec integrations.
|
Source ra,dec, flux and AST rise
times (top)
processing:x101/ao19/sources/srcsched.pro
Ip addresses (top)
The ip addresses, gateways to use:
- 192.65.176.1. observer computer in wapp
room.Online Gateway for all byu/ao19 devices to use.
- Will enable them to talk to the cor online datatking
computer
- 192.160.174.7 cor online datataking
computer (in wapp room)
- This sends command to byuhost and the ao19 cal control.
- 192.65.176.160: byu host
in transmitter room in dome
- listens on port
5010. cor computer will talk to it
- Will take to cor computer at : 192.160.174.7
- It is connected via a 1 gigabit link to doJ1331+305
133108.29 303032.96 j
14.5
3C286
wnstairs.
- will the observer gateway be a problem for the high speed
data xfer?
- 192.65.176.161: ao19gpib . this is the gpib
computer in Cornell rack on rotary floor.
- It is used for monitoring of dewar info. Not needed for data
acquistion.
- 192.65.176.162: ao19cal
. controls which dipole cal is enabled.
- Receives commands from cor.
arduino cal ctrl (top)
There is a cal multiplexor in the Cornell rack
on the rotary floor. It selects which dipole will receiver the cal
rf signal (from the noise diode)
byu documentation
20jun13 weight on rotary floor (top)
The weights on the turret floor for the jul13
experiment are:
equipment
|
weight (lbs)
|
notes
|
dewar
|
400
|
495 with mount - 95 lbs of
mount
weighted in xmter room.
|
dewar mount
|
40
|
guess by steve
|
Cornell rack
|
450lbs
|
weighed in transmitter
room.(450)
includes most cables/
|
byu rack
|
195 lb
|
weighed in xmter room
no cables
|
total
|
1085bs
|
|
rcv
|
weight (lbs)
|
notes
|
sbh
|
150
|
denis weighed it in lab
|
cbh
|
250
|
|
800
|
85
|
just used value from old 610
system
probably light since we have refrig
|
sbw
|
244
|
|
cb
|
254
|
|
total
|
983
|
|
So we will be adding 102 lbs extra to the
floor.
Other:
- byu rack in transmitter room: 683 lbs (no
cables included). weighed in transmitter room
- maybe 50lbs for cables
- 57" high (with castors), 21" wide, 35.75" deep
- 30amp circuit into box,. single phase.
Results:
BYU plots/images (top)
- Updated to 30oct13 version of
images.
- Beam patterns:
- 15x15 grids:
- 26jul13 J2123+250 @ 1400.0977
- 28jul13 J2014+235 @ 1399.6094
- 02aug13 J1330+251 @
1394.8242
- 31x31 grids
- 02aug13 J2014+235 @ 1664.707
- 02aug13 J2232+117 @ 1399.707
- sensitivity grids:
- 26aug13:
J2123+250 15x15 (.pdf) this is german's
version with the dipole positions layed out over the grid.
- 16
sensitivity grids (.pdf)
- sent 30oct13
- Some of the grids compare using the before and after map
noise fields.
-
Page
|
date
|
grid
|
noise
|
zaoff
|
freq
|
src
|
flux
|
obs/comments
|
1
|
26jul13
|
15 x15 |
before
|
12.2
|
1400.1-1409.9
|
J2123+250
|
10.34
|
1,2 same map
different offs.
|
2
|
after
|
6.8
|
1400.1-1409.9
|
|
3
|
28jul13
|
15 x15 |
before
|
6.0
|
1399.6-1400.1
|
J2014+235
|
13.6
|
|
4
|
after
|
12.8
|
1399.6-1400.1
|
|
5
|
30jul13
|
15 x15 |
before
|
9.3
|
1392.5-1397.4
|
J0318+164
|
7.7
|
|
6
|
after
|
18.2
|
1392.5-1397.4 |
|
7
|
30jul13 |
15 x15 |
before |
13.7
|
1392.5-1397.4 |
J2232+117 |
7.2
|
|
8
|
after |
7.5
|
1392.5-1397.4 |
|
9
|
02aug13 |
15 x15 |
before |
14,7
|
1392.5-1397.4 |
J1330+251 |
7.0 |
|
10
|
after |
8.3
|
1392.5-1397.4 |
|
11
|
02aug13 |
15 x15 |
before |
8.5
|
1662.4-1667.2
|
J1845+098 |
4.16 |
|
12
|
after |
10.5
|
1662.4-1667.2 |
|
13
|
02aug13 |
31x31 |
before |
16.9
|
1401.3-1402.2
|
J2232+117 |
7.2 |
finished 04aug13
|
14
|
after |
12.3
|
1399.3-1402.2
|
finished 04aug13 |
15
|
02aug13 |
31x31 |
before |
13.8
|
1665.3-1667.2 |
J2014+235 |
13.6 |
finished 04aug13 |
16
|
after |
6.8
|
1662.4-1667.2
|
finished 04aug13 |
- yfactors:
- moon:
- 03aug13: yfactors formed
beams on moon (@ 1665 MHz)
- Note: these are actually (YF- 1) (on-off)/off
- 15x15 using 02aug13 J1330+251 grid
- 31x31 using 02aug13 J2014+235
- Sources:
- 02aug13:
B1843+098 (J1845+097) @1665MHz (.pdf)
- The plots only show on,off difference for beam 1.
Looking at the logfiles, we did an on,off for beam 1.
- The plot label says 1397.7539.. but i think this was
1665 MHz?
- file: yfactors_08_02_2013_eve_yfactors_4p16Jy_1665MHz.pdf
25-29jul13:Calibration run results: (top)
x102 calibration scans were done using ao19.
The cal never worked so there is no Gain or Tsys value. We tried
various setups:
- 25aug13 - Search for best turret position:
- data taken with turret positions 161.74 and 161.40.
- 26aug13 - Verify data with "best" turret position (161.60)
- 27aug13 - Take data with dewar 1" below focus
- 29aug13 - Take data with dewar back in normal focus position.l
The plots
show the calibration results (.ps) (.pdf)
- Page1: SEFD, beamwidths, sidelobe height using all thedata.
- Top: SEFD in Jy
- Middle: the beam width in Arc seconds
- red: za beam width
- green: azimuth beam width
- colored (center symbols) average beam width
- Note that he azimuth beam width does not increase with za
while the za beamwidth does (because of the za spillover).
- Bottom: average 1st side lobe height.
- Page2: compare calibration while in focus and 1 inch out
of focus.
- The red symbols show data taken on 27aug13 while the dewar
was 1 inch below the nominal focus.
- There is not much change in the results ... maybe a slight
rise in sefd,bmwidth at za=12,13.
- Page 3: pointing error using all the data
- This includes the data on 25aug13 when the turret was not in
the final position.
- the rms error is 5.36 ,8.34 asecs (za,az) is small compared
to the beam size.
- Page 4: pointing error using data taken in the "best" turret
position (161.6).
- the turret was moved so that the mean azimuth error
went to 0.
summary:
- The sefd is about 14 Jy using dipole 1 and the ao system
- The average beamwidth is about 190 Arcsecs
- The average level of the first sidelobe is -14 db
- The pointing error was small
- moving the feed 1 inch down in focus did not change the
pointing or sefd very much.
processing:
x101/1307..25,26,27,29/ao19x102.pro,
x101/projects/ao19/procdata/x102dat.pro
On 30jul13 scans were done across the moon.
Data was taken at 1400 MHz.
- Scan 1: ao19 dipole 1 using ao system.
- start 1 deg off moon (in za), drive on, off , and then
back on.
- Scan2: ao19 dipole 1 using ao system
- scan across the moon (in za direction) then come back
- Scan3: lbw using ao system with linear polarization.
- do cal on,off 1 degree off moon (in za direction)
- drive across the moon and then come back
- Use cal to put data in degrees kelvin
- Use measured cal deflection in degK to put ao19 scans in deg
K.
The plots show the results of
scanning across the moon on 30jul13 (.ps) (.pdf):
- Page 1: scanning across the moon using AO19 with AO system
- Top frame:scan1: total power vs time .
- Black is polA, red is polB.
- The data has been normalized to Tsys off the moon .. so
this show TonMoon/ToffMoon.
- The ratio is 2.6 polA, 2.7 polB
- 2nd frame: scan1: total power (degK) vs distance from the
moon center.
- The distance from the moon was computed using the az,za
encoder values (after model removed) and the ephemeris
file az,za ,
- The data was scaled to degK using the (moon-sky)
deflection measured with lbw (193.1K ..see page 2).
- TsysA is 111.5, tsysB is 122.0 K
- Note:
- Off moon Tsys=(Trcv + Tspill + Tsky)
- on moon Tsys=(Trcv + Tspill + Tmoon)
- OnMoon - Offmoon = Tmoon - Tsky
- Tsky is typically 6K at 1400 MHz (as long as
you're not in the plane).
- 3rd frame:scan2: total power vs time
- german changed the lna bias voltage to 3.05 Volts before
this run
- bottom frame: scan 2: total power (degK) vs distance from
moon center.
- TsysA=112.6, tsysB=119.1
- TsysA went up a little, tsysB went down.
- It looks like there is some polarized power coming off the
moon scan. The scan1,2 change may be from the change in the
parallactic angle.
- Page 2: scan across the moon with lbw
- A cal scan was taken 1 deg off the moon. It was then used to
convert all of the lbw data to degK.
- Top frame: total power (degK) vs time as we scanned across
the moon.
- 2nd frame: total power (degK) vs distance from center of the
moon.
- tsys off the moon was: polA 30.7K , polB 31.3K
- The average (Tmoon - Tsky) = 193.1 K
- 3rd frame: Over plot lbw scan with 2nd ao19 scan
- bottom frame: Over plot lbw scan with ao19 scan2 after
removing Tsys off moon.
- This shows the shape difference for the two scans. lbw has
a sharper drop when moving off the moon than ao19.
Summary:
- Tmoon - Tsky was measured to be 193.1 K at 1400 MHz
- Tsky is about 5-6K so Tmoon is probably close to 200K
- This is smaller than the values don found in the literature.
- AO19 Tsys 112 polA, 120 polB. Some of this difference
may be from the polarized power off the moon.
- The MoonOn/MoonOff ratio was polA 2.6, polB 2.7. This
compares with what by measured on 03aug13.
- The ao19 beam has a slower drop off than lbw.
- The beam width of ao19 is narrow than lbw (190 vs 200
asecs), but the average sidelobe height of ao19 is larger (-14
vs -16 db).
- There is very little change in power .6 deg degrees off the
moon center. So our 1 deg offs are probably not being
contaminated by the moon.
processing:
x101/projects/ao19/procdata/moon30.pro
03aug13: yfactors, sefd @ 1400 &
1665MHz (top)
On 03aug13 on,offs were done on source
J0603+219 (B0600+219):
- The source flux is:
- 1400 MHz: 2.69 Jy
- 1665 MHz: 2.44 Jy
- The off was 1.5 deg away in azimuth
- dipole 1 was used. with the byu system and with the ao system.
- Data was taken at 1400MHz and 1665 MHz.
The plots show the
results of the on, offs (.ps) (.pdf)
- Page 1: Yfactor, sefd's
- top: yfactor (on/off) dipole 1 . plotted vs frequency.
- Purple
: AO system ratios
- Blue
: byu unformed be
- triangles: polA, * polB
- red : byu
formed beam
- Bottom: sefd vs frequency
- 1665 has a lower sefd (4-9) than 1400 MHz (7-12)
- polA has a lower sefd than polB (except for ao 1400 MHz)
- Page 2: ratios of yfactors and sefd's
- This shows the ratios of:
- formed beam/unformed beam
- byu Unformed beam/ ao unformed beam.
- You can see how things improved as you move from 1400 to
1665.
- Top: ratios of yfactors:
- Larger yfactors are better. ratio > 1 --> numerator
is better.
- red:
byu formed beam/ byu unformed beam
- Blue:
Byu Unformed Beam/ AO (unformed) beam
- Botom: Ratios of SEFD
- Smaller SEFD'S are better : ratio < 1 --> numerator
is better
SUMMARY:
The table shows the yfactor and sefd results.
Freq
MHz
|
Measurement
Source
|
Yfactor
|
SEFD
|
1400
|
ao
|
1.22
|
1.23
|
12.23
|
11.70
|
byu
Unformed beam |
1.26
|
1.22
|
10.34
|
12.23
|
byu formed
beam |
1.39
|
1.36
|
6.90
|
7.47
|
1665
|
ao |
1.37
|
1.28
|
6.59
|
8.71
|
byu
Unformed beam |
1.40
|
1.31
|
6.10
|
7.87
|
byu formed
beam |
1.51
|
1.38
|
4.78
|
6.42
|
processing:
x101/130803/ao19.pro
03aug13: Byu system: yfactors, Tsys on
moon. (top)
We did on/offs on the moon at 1400 and 1665 MHz with the
byu system. The yfactor was then computed for each beam.
The
plots shows jay's yfactors with bad beams removed (.pdf)
The second plot showsTsys for
various moon yfactors (.ps) (.pdf)
- Black is Treceiver + Tspillover
- Red is Treceiver + Tspillover + Tsky
- Tsky was set to 6 K
- The top plot uses Tmoon = 200 K
- This is the value measured with lbw on 30jul13.
- the bottom plot used Tmoon=220 K
processing:
x101/projects/ao19/procdata/tsysVsYf.pro
01,03aug13: Yfactors, tertiary skirt,
moon, Ao system. (top)
Moon on,offs were done using the ao system :
- 01aug13: 1400 MHz, screen not on the tertiary
- We did a single on , off stepping in azimuth
- 03aug13: 1400, 1665 MHz screen on the tertiary.
- For each frequency we stepped off in azimuth and in za.
The plots compare the results
with/without the tertiary screen (.ps) (.pdf):
- Top: 1400 MHz yfactors vs frequency
- Skirt on: black,green polA, red, blue polB
- skirt off: purple,dark red
- Looks like there is a small slope in yfactor vs frequency at
1400 MHz.
- The Tsys values printed assum Tmoon=200K, Tsky=6k (these
were measured 30jul13 with lbw)
- middle: 1665 yfactors
- Skirt on: black,green polA, red, blue polB
- No tsys values are listed since we didn't measure Tmoon at
1665 MHz.
- Bottom: 1400 MHz ratio YfactorScreenOn/YfactorScreenoff
SUMMARY:
- The azimuth and za steps gave close results
- PolB is worse than polA at 1400 MHz and 1600 MHz
- The tertiary skirt decreases the spillover. Tspill occurs in
both the numerator and Denominator of Yf:
- Yf=(on/off) = (Tmoon + Trcv + Tspill)/(Tsky + Trcv +
Tspill).
- The skirt increased the yfactor by 4%.
- Assuming Tmoon=200, Tsky=6 K, Tsys decreased by about
6%.
processing:
x101/projects/ao19/procdata/moonskirt.pro
02,03,04aug13: yfactor, SEFD vs
frequency (top)
Frequency scans were done on 02,03,04 aug13 to
measure the yfactor and SEFD vs frequency using the ao system. The
setup was:
- Use the interim correlator.covering 100 MHz (4x25MHz) per
integration. There were 1024 channels across each 25 MHz.
- Do 5 freq integrations centered at: 1250,1350,1450,1550,1650
MHz
- At each frequency do a 1 minute position switch (1
minute on, 1 minute off).
- The sources used were:
- J1330+251 za =7.0 deg
- B0600+219 za=4.6 deg
- B2128+048 za=14.4 deg
- On/Off was computed for each source
- The flux vs frequency was divided into (on-off)/off to
normalize the Yfactors to a 1 Jy source
- On/Off for B2128+048 was increased by .01 to compensate for
the higher tsys (the za was higher)
The plots show On/Off and SEFD vs
frequency (.ps) (.pdf):
- Page 1: On/off vs frequency for polA and polB.
- the bottom plot shows the source flux vs frequency for each
source.
- Page 2: Normalize (on-off)/off to a 1 Jy source
- frame 1,2: normalized on/off to 1 Jy.
- The green trace (B2128+048) shows a lower value (because
of the higher za).
- frame 3,4: overplot on/off after correcting B2128+048 by
.01.
- Page 3:Average On/Off and SEFD vs frequency.
- The on/off and SEFD for the 3 sources were averaged and then
plotted.
- 40 channels at both edges of each 25 MHz bandpass were not
plotted. The filter falloff was causing some unwanted
structure..
SUMMARY:
- The SEFD ranges between 17 Jy and 7 Jy between 1200 and 1700
MHz
- SEFD for pol B is generally higher then polA
- at 1650 MHz SEFD polB is 25 % higher than PolA
- at 1400 MHz the sefd's for polA and polB are pretty close.
- We may be seeing some resonances.
- The 25 MHz band around 1330 MHz was wiped out by the
punta Borinquen radar.
processing:
x101/projects/ao19/procdata/freqscan.pro
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