Links:
04apr12: can we replace the 430tx with a ring of amiser panels?
27mar12: modAnode not staying all the way off after beam off.
16jan12: waveguide measurements
19oct10: scope trace of protect turnoff
07oct10: 430 transmit pulse sequence timing
07aug10: 1 Mhz chirp transmitter pulse output
03aug10: measure klystron output of 1 Mhz chirped signal using scope
Hagens 430tx operations and maintenance manual

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27mar12 Mod anode not staying completely off after beam off.

    The mod anode was not staying completely off after the rf pulse turrned off. The mod anode output of the transmitter console is plotted below for various HV settings. These measurements were taken with a single klystron (klyA) installed.'

• The yellow trace is the modAnode. The green trace is the beam (or rf?).
  
• hv=60KV (.png)
  
• hv=70KV (.png)
  
• hv=80KV (.png)
• The modAnode rises 1.4 divisions in about 800 usecs.
  
• The modeAnode on to off is  5.8 divisions. This is about 40 Kv
• So the modAnode is moving 1.5/5.8 - 25% of the modAnode voltage during this time.. about 10Kv
• This  is a lot more than the 5kv supply so this supply is probably not the problem.
  

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19oct10: scope trace of protect turnoff. (top)

    On 19oct10 we did a test to look at how quickly the 430 ch  receiver could be turned on after the rf pulse of the transmitter goes off. The setup was:

• High voltage off, ipa off, system on.
• 429 Mhz cw tone transmitted from hilltop antenna
• rf signal ch crr1, 30 MHz IF, to 30 Mhz amplifier, no filter, and then IF to scope.
• thumbwheel delays set to 1 usec.
• Scope triggered on falling edge of rf pulse.
  
• The image below shows the signals:
• Rf pulse:
  
• leaving hagens box.
• protect cmd: 
• Leaving hagens box.
• there is a 6 usec delay in hagens box from rf falling to protect cmd falling
• ACK:
  
• At hagens box.
• The protect cmd falls and is sent upstairs.
  
• The monoplexor waits 20 usecs then the diode current is turned off
• When the current thru the diode drops to a certain level, the ack level will drop
• it then comes back downstairs and shows up on the output of hagens box.
• Ack drops (downstairs) 27 usecs after protect cmd drops (downstairs).
• This is the 7 usec round trip time + the 20 usec monoplexor delay
• IF signal: 
• This is the 30 Mhz IF voltage.
• There is a spike 8 usecs after protect falls.
• this changes with the thumbwheel delay.Increaing this delay moves this to the right.
• The wheel is labeled IF and LO blanking.
  
• Quest: why the 8 usec delay from protect? Is this a round trip delay??
  
• After 8 usecs the noise increases. This is coming down the cable from upstairs (but the monoplexor is still active). I wonder if the upstairs rf blanking is still active.
• When ACK falls (downstairs) we wait 12 usecs before the IF signal comes back up.
• Quest: where is this delay coming from?

Sumary:

• rf Falls to IF up: 46.5 usecs.
• This corresponds to a minimum range of:
• (46.5 -7)*.15=5.8 km.
  
• The -7 is the 3.5 usecs for rf pulse to go up and the 3.5 usecs for the IF Signal to come down.
  
• 12 usecs of unknown origin ack falls to IF up.
  

ACK at hagens box, IF SIGNAL, RF pulse at hagens box, protectCmd leaving hagens box

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07oct10: 430 transmit pulse sequence timing (top)

The picture below shows the 430 transmiter transmit sequence. a (.pdf version) is also available)