Directions for using 850 RX
Date: Jan 20, 2009
By: RAChamberlin
Location of this file: puuoo.submm.caltech.edu//850Rx_directions.doc
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1.Assume that the PLL is turned on. (If not consult appendix).
2. UIP> LO 12CO7-6/LOCK=SMA/IF=1.5
3. UIP> TERT CASS
4. UIP> POINT 850_CASS (assumes 850GHz mounted on LHS, Cass focus)
5. Remove plexiglass from M3 and M5 mirrors in relay optics.
6. Turn rx with handpaddle (same as side cab)
Manually bias SIS junction to 2.1 mV
Set magnet to about 80ma.
Sweep "B" field and find minimum in Josephson noise near 80ma.
7. After gunn is locked in the normal way, adjust multiplier tuners until until there is about 20uA of current on the SIS junction.
8. If Antennna computer is restarted, or you are turning on the 850 GHz rx for the first time then the HP83620B will come up in the default state which is with the RF power off and set to 17dBm. Go to local mode and turn the RF power to about 18 dBm. Turn the RF power on. Then try locking the gunn. The green LED on the lock loop may not illuminate if either the power from the synthesizer is too high or the power from the Gunn hitting the harmonic mixer is too high. The power from the synthesizer can be controlled from the front panel. A variable waveguide attenuator is being provided to reduce the amount of Gunn power hitting the harmonic mixer. If you a “power user” you can check the diagnostics from the SMA PLL to try to get the harmonic mixer IF power in the range of around 2 volts. See appendix for instructions on using the SMA PLL software.
Turning off 850 rx and using a sidecab rx
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0. Short the junction with the handpaddle to "main"
5. UIP> POINT 230_SIDE
APPENDIX: Details about using the SMA PLL for power users. Originally written for Barney.
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1. From a xterm login ssh in to the antenna computer cso account and
start the PLL.
unix_host> ssh hau -l cso
(enter password)
Eg.
hau[619]$
hau[620]$ cd newpll
hau[622]$ cd bin
hau[625]$ csopll -p /dev/sio1
Probing the RS485 network (addresses 0-7) .... 0 1 2 3 4 5 6 7 Done.
Found 1 boards
Using LO Board at address 7
hau:microcontroller01> help
Most of the 32 commands take an argument (separated by a space):
......
network - Probe for boards on the RS485 bus or simply query the boards
found during the previous probe: network [probe]
pll - Turn PLL on, off or bl[ink] <msec>
q - Quit the program
quit - Quit the program
s - Read or set the current microcontroller slave address
v - Measure & report A/D voltages from the current slave
hau:microcontroller01> network
RS485-address Board Type EPROM version SRAM version LoBoard subType
00 = .
01 = .
02 = .
03 = .
04 = .
05 = .
06 = .
07 = LO Board 0x4c 0x31 A1: 177-256 GHz Port 3
1 fully-functional LO boards present
hau:microcontroller01> s 7
Note: Board may be present at another address such as 01.
hau:microcontroller07> v
IF Power = 0.000 Phase Noise = 0.000 RATIO = 1000.0
TEC Temp=0.015V, Gunn Bias= 0.935V, Ambient Temp= 33.6C (00068)
18V Supply= 18.360, 10V Supply= 10.179, 10V TEC Supply= 0.030
hau:microcontroller07> gunn on
Gunn is ON
PLL is OFF
sideband = Upper
hau:microcontroller07> pll
Gunn is ON
PLL is OFF
sideband = Upper
hau:microcontroller07> pll on
Gunn is ON
PLL is ON
sideband = Upper
hau:microcontroller07> v
IF Power = 2.132 Phase Noise = 0.183 RATIO = 11.648
TEC Temp=0.015V, Gunn Bias= 9.957V, Ambient Temp= 33.6C (00068)
18V Supply= 18.360, 10V Supply= 10.179, 10V TEC Supply= 0.030
3. Tune the Gunn in the normal way looking at the HM 109 MHz IF on the HP
spectrum analyzer. Some diodes on the PLL module illuminate when
you get lock. When the lock is centered in the PLL control
voltage range the center diode only is illuminated (there is a set
of three green ones on the PLL controller board on the
side of the rx.)