Directions for using Frank’s RX (including LO hookup)

Date: July  24, 2009

By: RAChamberlin

Location of this file:  ulu//home/cham/web/CSOmemos/Franks_Rx_directions_LOhookup.doc

 

 

  1. IF PLL is connected  to Barney then hook it up to Frank's rx.  (Otherwise, skip this step and proceed to Step 1.)

     ! Wear a wrist strap!

     a.  Shut off power to LO plate

     b.   disconnect SMA cable on Barney's harmonic mixer (HM).    Leave 1dB pad on HM.  Put a shorting cap on  the HM.   Connect the cable to Frank's Rx HM.

     c.   disconnect SMA cable on Barney's gunn.   Put shorting cap on Gunn. Connect cable to Frank's rx gunn.

     d.  disconnect cable to IF processor from Barney's warm IF amp.  Connect to output of IF amp on Frank's rx.

     e. Turn on PLL power.  See appendix for turning on PLL.

    

 

.

1.Assume that the PLL is turned on.  (If not consult appendix).

 

2. UIP> LO  12CO2-1-3/FORCE=NOMIRROR /LOCK=SMA /IF=5.0

 

3. UIP> SPEC/FFTS=5.0/AOS5/RESTART

 

 

            Note:  LO/IF=5.0 sets the Gunn LO so that Doppler tracking always centers the source's expected VLSR  at 5.0 GHz in the IF.   The FFTS is a 0.5 or 1GHz wide spectrometer that can be moved around in the IF band.  FFTS=5.0 centers the FFTS band on 5.0 GHz.  For more details see  http://puuoo.submm.caltech.edu/docs/hiro/ffts/FFTS_Instruction.html.

 

 

 

 

4. UIP> TERT CASS

 

5. On SIS bias box, make sure SIS Voltage is zeroed.  Unshort bias with toggle switch.    See Figure 1.

 

     5.1 Set Bias to about 2.27 mV

 

6. Set magnet field to about 47 mA. 

 

7. After gunn is locked in the normal way, open LO chain attenuator until there is about

     80uA of current on the SIS junction.    Note that the SMA PLL’s might get a false lock 109MHz from the correct Gunn frequency.  Therefore once you acquire a lock you should “hunt” a little bit around your lock to see if there is a stronger lock.  If you find a stronger lock that is the one you should be on.

 

 

8. If Antennna computer  is restarted, if you are changing from a side cab receiver, or you are turning on Frank’s rx for the first time  then the HP83620B  (or Agilent 8257D) may 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 down to about 10dBm, or less.   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.    Do not adjust the blue attenuator on the harmonic mixer unless you know what you are doing.

 

 

 

Figure1:  Bias boxes for Frank’s Rx

 

 

  1. Fine tune magnet current to verify you have minimized Josephen current.
  2.   Fine tune SIS voltage bias to put on peak IF power.

 

  1. Make sure you remove mirror covers on the M3 and M5 relay optics mirrors.  Make sure the relay optics M3 mirror is rotated to direct the sky beam to Frank’s rx.  When rotating the mirror  turn it by the base, not by the mirror flat.  Otherswise you may alter the beam alignment.

 

  1.   UIP> POINT Z_REX

 

 

 

Turning off Frank’s rx and using a sidecab rx

 

.

  1. Turn the bias on the SIS box to zero.  Short the junction with the toggle switch

 

  1. Turn the magnetic field to zero.

 

  1. Leave the power to the bias boxes on

 

  1. UIP> LO 12CO2-1-3/LOCK=NEW/IF=1.5

 

  1. UIP> SPEC/FFTS/AOS5/RESTART

 

 

  1. UIP> TERT SIDECAB

 

 

  1. UIP> POINT 230_SIDE

 

 

 

APPENDIX:  Details about using the SMA PLL for power users.  Originally written for Barney.

 

.

 

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

             using default board address = 1

             trying to open terminal using /dev/sio1

             Terminal successfully opened.

             Probing the RS485 network (addresses 0-7) .... 0 1 2 3 4 5 6 7 Done.

             Found 1 boards

             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 =    LO Board       76 = 0x4c     49 = 0x31  B1: 256-360 GHz Port 7

                 02 =    .

                 03 =    .

                 04 =    .

                 05 =    .

                 06 =    .

                 07 =    .

             1 fully-functional LO boards present

             hau:microcontroller01> s 1

 

Note: Board  may be present at another address such as 06.

 

 

            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