Project TBASERDN040219

February 19, 2004

Continuing Baseline tests Q-band rx.  
Weather is cold, intermittant snow, mostly cloudy.

Tsys approx. 80K.

Setup ACS to 800MHz BW.

ACS in 4 bank, 2 samplers/bank mode.


L1 -> ODM1 -> OR1 -> CM1 -> SF1 -> ACS J1 (bank 1, rcvr 1)
		     CM2 -> SF2 -> ACS J3 (bank 2, rcvr 1)

R1 -> ODM3 -> OR3 -> CM5 -> SF5 -> ACS J2 (bank 1, rcvr 2)
		     CM6 -> SF6 -> ACS J4 (bank 2, rcvr 2)

L2 -> ODM5 -> OR5 -> CM11 -> SF3 -> ACS J5 (bank 3, rcvr 1)
		     CM12 -> SF4 -> ACS J7 (bank 4, rcvr 1)

R2 -> ODM7 -> OR7 -> CM15 -> SF7 -> ACS J6 (bank 3, rcvr 2)
		     CM16 -> SF8 -> ACS J8 (bank 4, rcvr 2)


The Q-band receiver is on the GBT.  Main goal today is to try to
reproduce the relationship between HFET bias and baseline ripple seen
on 2/13/04.  Starting with load paddle IN, T=302K.  Tscan=60s.
Lo1A=9250 (Fsky=43000).

Scans 5-14  Bias on all four channels first stage Vd1=1.20, Id1=1.5mA.
(Spectrometer bombed in scan 15. Restarted and resetup.)

Scans 16-25 R2 bias -> 0.89V, 2.1mA
Scans 26-35 R2 bias -> 1.2V, 1.5mA

Load paddle OUT, on sky at access.
Scans 36-45 R2 bias @ 1.2V, 1.5mA
Scans 46-53 R2 bias -> 0.89V, 2.1mA
scans 54-57 R2 bias -> 0.89V, 2.6mA
Scans 58-72 R2 bias -> 1.2V, 1.5mA

Everyone off the GBT now.  Will run a couple of longer scans using
on/off procedure.  

scans 75-76  xtrackonoff  01:31:00;47:00:00 J2000 T=302s.

Changing to DCR.  tau=0.2s, BW IF Rack = 1280MHz, BW AF Rack 800MHz.
T=302s

Scans 77-78  TpWcal

Scans 79-80  SwPwrWcal

end of time.