- 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
- The interim correlator monitored the arcing using the dome 430
- 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.
- recorded tube waveforms on oscilloscope
- tx 2,1,4,5, and then 6
- look at the ratio of the tube output stages for each
- 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)
- 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
- 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
- Occasional arcing was seen with the interim correlator
Comparing the tube monitor
- tx3,tx6 had circuit breaker problems .. no 208 volts in
- tx6 came back up. tx3 stayed down.
- measured the tube waveforms for tx 1,2,4,5,and 6 (need to
- occasional arcing. We need to run the 430 tx to get a more
sensitive measure of any arcing.
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