Background:

• Problems during previous test  01feb17:
• tx 4 and tx 6 had arcing in the HV vault.
  
• tx 2 (running at 5 Mhz) dropped its power from 80KW to 50KW by itself. Looked like the broad band power output decreased.
  

What we did:

• mesh was at 5Mhz position. used 5 mhz rcp
  
• 430 transmitter was not used, since the receiver was being repaired.
• The interim correlator monitored the arcing using the dome 430 receiver.
  
• Only used 5 MHz for the test. freq=5.125 MHz
• 11:45 started to bring up transmitters
• Generator breaker for hf tripped on startup. had to reset.
• 12:12 6 tx at 70 KW each.
• 12:27 tx3 circuit breaker fault. no 208 power ..
  
• tx3 stayed off for rest of day. didn't want to come back up.
  
• 12:45 tx 6 circuit breaker fault.
• stayed off until 14:45
• recorded tube waveforms on oscilloscope
• tx 2,1,4,5, and then 6
• look at the ratio of the tube output stages for  each tx.
• setup:
• chn1: low level amp (with 6db pad)
• chn2: rf output ipa
  
• chn3: rf output drv Ampl anode
• chn4: xmter output fwd power sample (after the filter)
• scope:
  
• 100k buffer, 100ns/division
• all channels 50 ohm termination, 250Mhz bw
• chn1 1volt/division (and 6db pad at input)
• chn 2-4 200 millivolts/division
• saved .isf files and jpeg images.
• recorded meter readings after each scope capture.
• 14:00 done with scope measurements tx 1,2,4,5
  
• bring tx 1,2,4,5 up 70 -> 80 KW
• 14:08 some arcing
• 14:43 bring tx 6 backup, then do scope measurements.
• 15:05 done with tx 6 measurements.
• 16:30 done with test. HF off.
  

Plots of output and drive power:

The plots show the data we took while the hf was on (.ps) (170207)

• The page has 3 frames:
• each color is a different transmitter (1 through 6).
  
• top  frame: rf power (in dbm) measured at the output of the rf coupler.
• middle frame: the same output power, but displayed in KWatts
• bottom frame:
• The synthesizer drive amplitude used
• The dashed green line shows when the rf was on
• the red line at the bottom is the total power from the carriage house 430 receiver (polA 425-435 MHz). When we have arcing, there are jumps in this power (rfi can also make jumps).
• tx 3 green line trips at 12.5, tx6 (lite blue) trips at 12.75
• 13.1 to 14. measuring waveforms on tx 1,2,4,5
• 14.0 increased power to 80KW on 1,2,4,5
• 14.75 brig tx 6 up to 70KW and then measure the waveforms with the scope.
• Occasional arcing was seen with the interim correlator monitor.
  

Summary:

• tx3,tx6 had circuit breaker problems .. no 208 volts in vault.
  
• tx6 came back up. tx3 stayed down.
• measured the tube waveforms for tx 1,2,4,5,and 6 (need to process).
• occasional arcing. We need to run the 430 tx to get a more sensitive measure of any arcing.
  

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