What we did:

• 10:00 - 11:30:  measured the currents in td8 cable with the rogowski coil while transmitting at 5.129 MHz
• 11:30 - 11:50 : bring up all tx using 8.175 MHz.. but we were transmitting out an open port (unconnected dummy load) rather than the antenna
• 12:06 - 13:00 : bring up tx 1,2  using  8.175 MHz (after switching to antenna port).
  

Transmitted power

    The plots show the transmitted power during the testing (.ps) (.pdf):

• Page 1: entire test.
• Top: dbm read back from the rf coupler
• bottom: power converted to dbm.
• 10:10 to 11:30 we were cycling the tx on 5 secs, off 5 secs..
• Page 2: drive level (exciter) from signal generator.
• top: signal generator as set by hfsynth program. Y axis is db below max drive
• bottom: measured output power (KWatts) for the given drive level.
• Page 3: drive level, power during rogowski test
• Top drive level.
• bottom output power (KWatts). peak hold values
  
• We were cycling tx on,off every 5 seconds.
• The estimated drive power during the rogoski test:
• tx1:25KW, tx2:21KW, tx3: 27KW, tx4:30KW, tx5:20KW, tx6:18 KW (radial pointing at td8).
• total tx power: 141KW
• Page 4: 8.175 MHz. drive level, measured power went transmitting into open port
• tx 2 and 4 were connected to dummy loads. They started to smoke (since the water wasn't circulating)
• tx 4 tripped (probably at 11.83 hrs).

Rogowski coil at 5.129 MHzMhz

• 5.129 MHz was transmitted
• We toggled the rf 5 sec on, 5 sec off.
• Measurements were done on the td8 cable
• all 6 tx transmitting
• only tx 6 transmitting (radial pointing at td 8)
• We also measured the current in the ground cable (from td8 cable to ground).
• The coil was  mounted on rightmost td 8 cable (with back to center of dish) above the ground cable connection
• we wrapped thin foam around cable to the thickness of the coil, then taped things closed.
• The preamp box sat on top of the limit switch box (next to jack).
• a 15' cable ran from the preamp box to the tek 5ghz scope.
• We put 2 chokes on each end of the 15' cable (multiple loops through the choke) to cut down  the scope from overloading at the transitions.
• The scope setup was:
• 20 mv/division,5ksmp sampling, 100000 points
• scope sample aliasing.
• The sine wave was 5.129 MHz. the sampling rate was .0002 seconds
  
• each .0002 sec sample moved 1025.8 5.192 MHz cycles, so 5 samples covered 1 sinewave cycle.
• We acuired a single traces on the scope and then stored them on a memory stick.

Voltage output by rogowski coil

• page 1:  20 seconds of data (full trace)
  
• top frame:td8 main cable, all 6 tx cycling
• You see the 5 second on, off cycle
• 2nd frame: td8 main cable, only tx6 (radial) cycling
• The peak went from 30 to 20 mv. About 70% of all tx on
• bottom frame: td 8 ground cable, all tx cycling
• peak value of 20 mv. 70% of td main cable with all tx cycling
• Page 2: blowup showing individual scope samples at turn on.
• The under sampling take 5 samples to cover a cycle (actually 6000 cycles).
• The + show the scope samples

 Currents in cables

   Using the rogowski coil calibration sheet, dana computed:

• main cable all tx: 30mv -> .85 Amps rms.
• main cable  tx 6 : 20mv -> .57 amps rms
• If we assume the  currents are linear with power, the currents expected during a heating r

• measurement	rogowski test		jun16 hf campaign
  	all tx	only tx6	all tx	only tx6
  power Out (KW)	140 KW	18 KW	500	85
  current (Amps rms)	.85A	.57 A	3 A	2.7A

  
  
• So we might see 3 + amps coming down a tiedown cable.
• about 2/3  of that goes down the grounding cable.

8.175 MHz into open port

• the heliax was connected to the output port that normally goes to the dummy load
  
• The output port that goes to the antenna was left open
• except that tx 2 and tx 4 actually had dummy loads connected to these ports.
• water was in the dummy load, but it was not circulating.
• The tx's were then switched to filter B (8 mhz) antenna.
• This routed  the output power to the open output port of the rf switch.
• The tx were brought up slowly. There was pretty high reflected power on the transmitters.
  
• Page 4 of the tx output power (see above) shows the output power (measured before the output rf switch) starting to go up around 11.75 hours.
• tx 4 tripped about 11.82 hours.
  
• the other tx got up to about 5 kw before we  shut them down (dummy loads started to smoke..)

    We then switched tx1 and tx 2 to antenna. They were brought up to about 20 KW and left there for about 20 minu

Summary

• Rogowski coil
• need chokes on line from rogowski preamp to scope.
• .85 amps rms at 140 KW 6 transmitters
• .57 amps rms at 18KW, tx6 by itself
• This was measured in  1 td cable.. there are 2 cables/tiedown and 6 cables in total.
  
• For an hf run we would have around 3 amps/td cable at 500KW
• The dummy loads had smoke coming out of them (with no circulating water). Not sure whether their calibration has been affected.
  

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