What we did:

• measured the phase at the output of the rf couplers relative to tx5 phase. We adjusted the synth phase to give us the correct phase to generate LCP and RCP (more info on needed phasing).
• move the mesh up +/- 2 feet from the 5 Mhz position and looked at the change in reflected power.

Plotting drive and rf power for the day.

The plots how the rf power, drive power, and total power monitored by the ch for the run (.ps) (.pdf)

• Page 1: xmitted power
• each tx is plotted in a different color
• top:  dbm read back by anritsu
• bottom: KWatts transmitted,
• At 10.9 we switched from lcp,rcp to moving the mesh.
• Page 2: power during lcp,rcp measurements
• top: synth drive in dbf
• bottom: KWatts transmitted.
• The purple line tx5 is the reference tx for the phase measurements.
• 1 other tx would be on at a time with tx5
• red: tx2, blue:tx4 did not have successful lcp,rcp phase measurements.
• Page 3:power during mesh motion
• Top: synth drive (dbf).
  
• up 2feet .. , down 2 feet, 0 feet (5 Mhz ref position), backup 2 feet.
• Bottom: KWatts transmitted.
• The reflected power was recorded manually (see below).

Measuring lcp,rcp phase.

The setup:

• We used the field fox in Vector voltmeter mode.
• tx 5 was the reference. It was plugged into channel A
• tx 1,2,3,4,6 were sequentially plugged into channel B
• The field fox was set to display A/B..
• Normally you would think to use B/A(ref) but..
•  The field fox measures leading phase, we needed lagging phase (that's what the synths use)..
  
• Matched cables went from the monitor cable panel to the field fox (tx5 ->portA, tx1,2,3,4,6 -> portB)

Making the measurement:

• Tx5 and TxN (1,2,3,4,6) were first plugged into the rf switch and anritsu.
  
• We did Tx5 ref with 1 other Tx at a time . All other tx's were at minimum power
• The drive level was adjusted to close to as high as it would go (without tripping).
  
• The phase was set to the theoretical value.
• We then plugged the cables into the field fox, and adjusted to phase to be close to what we wanted.
• After doing rcp, we then did lcp for the same pair.

The table shows the 8.175 Mhz  results:

Note: this table is not kept up to date. For current value see phasing the dipoles page

Notes:

• 160920:
• Tx2 : tripped with reverse power at 40 KW. did not measure
• Tx3 : could not  raise power above 40 KW without tripping with rvs power. Did measurements at 40 KW
• Tx4:
• monitor cable tx to control room intermittent, replaced it.. then anritsu monitoring worked.
• got to 32KW (-6.5 dbf) and reverse power meter jumped to 15 Kw with no trip.
• prior to the rvs power jump, the phase was very close to correct. At the rvs power jump, the phase jumped by 20 degrees. We decided to skip this tx.
• 160921:
• Tx2: had high reflected power (11.1) .. but no trip. (after adjusting meters)
• Tx4:
  
• lots of arcing at low power. couldn't measure.
  
  

Reflected power vs mesh height.

• Place mesh at a particular height
• 2feet below 5mhz position, at 5 mhz position, 2 feet above 5 mhz position.
• 2feet is the linear distance the support cables. The actual height change is 2*sin(alfa) where alfa is the angle between the mesh cable and a horizontal line.
  
• we used tx 1,5, and 6
• set the phase for rcp (measured earlier this same day).
  
• Bring the tx's up (together) from 40 KW to 80KW in 4 steps
• At each step measure the transmitted power (from the rf coupler) and the reflected power (from the meter on the tx)

The plots show the reflected power vs the mesh height (.ps) (.pdf)

• The colors are the mesh heights:
• black: 2 feet below 5 Mhz position
• red: at 5 Mhz position
• green: 2 feet above 5 Mhz position
• Frame 1 is Tx 1. It goes to dipole 2A (radial dipole)
• Frame 2 is Tx 5. It goes to dipole 6A (radial dipole)
• Frame 3 is Tx 6. It goes to dipole 6B (tangential dipole).

Mesh motion summary:

• -2 feet had the largest decrease in reflected power.
  
• 0 and +2 feet had similar results.
• The tangential dipole saw a larger change in reflected power with height that the 2 radials.
• The dropoff in reflected power for tx 5 at 80 KW was from tx 1 tripping. This causes less coupling into tx5.
• 
  

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