STUDYING RF PHASE DRIFTS IN THE H1 RF SOURCE OSCILLATOR SYSTEM IN CER:  
WORK PERMIT 6453  Dick Gustafson
TUES MAINT 1/25  1700 UTA(0900pst) to 2000 (1200pst)   at CER ISC Racks C# and C4.
Maintenance period access...

This  was motivated by a search for a cause of a 1/2 and 1 Hz comb of lines seen in long CW GW searches,
multiday integrations,  and having noticed apparent OSC phase drifts in the commissioning/shakedown era.
The scenario is the 1 PPS (1Hz) basic correction interval modulates the RF in random but sharp interval way.
A second 1 Hz theory was power modulation associated with the 1Hz on/off of perhaps a 100 LEDS
switching perhaps 1 amp in the OSC SOURCE power system; reprogramming, ie removing this 1 Hz variable 
perhaps changed, but did not eliminate the 1/2 Hz comb effect.

Results:  so far... 
We verified the 10 MHz OSC-VCO phase drifts/swings (relative to 10.000...MHz ref)  +- ~ 5 to 25 ns, 
over randomly different swing periods of ~ 4 - 30 sec.
The phase swings back an forth relative to a freq tweeked reference osc signal as seen on a TEK 3032
Oscilloscope; the ref OSC triggers scope; observations are made with MK I Eyeball.

> The phase drift seems ~ constant in two drifts speeds for  +, and - directions; 
  and swings... ie drifts of varying periods  ~ < 4  to ~30 sec.
 
The 10 MHz OSC was selected first (today) as having a freq with a convenient reference stable 
tunable oscillator units available: << .1 ns sec drift: 
a "tuneable" SRS SC-10 very stable 10.000000 MHz VCO;   and an SRS FS725 Rb87 Rubidium frequency 
standard ("atomic clock ") 10.000 MHz.  This provides a stabilized 10.00000000000 MHz reference    
very slowly tunable over very limited range.  Used here first to verify the stability and
tunability of the ref oscillators and learn subtleties.

PLAN:  We hope to devise a practical scheme to test all or most of the OSCILLATORS in the LHO CER...
       are they the "same"?  or  what?
       ..next maintenance or opportunity....to come up with a plausible Drift model
       and understand consequences.