Intro

    The rf couplers sample the transmitter output and reflected power. There are a set of couplers for each transmitter band.

• Band A: 5.125  MHz band: .. coupler range: 5.0 to ?/
• Band B: 8.175 MHz band: doupler range: 6.69 to 9.14MHz

    Each coupler set has:

• 2 60 db couplers with forward and reverse ports
• The 2 forward power ports are used by the tx meters, and the anritsu.
• the 2 reverse power ports are terminated
  
• 2 50 db couplers with forward and reverse ports
  
• The two forward power ports are terminated
• the 2 reverse power ports are used to by the tx meters for reverse power.. and eventually by dana's phase monitoring.

    Since  the 5.15 and 8.175 MHz couplers have different frequencies ranges, they need to be calibrated separately.
We looked at multiple 5 MHz couplers and their values were similar.

    We use the forward power couplers to log the transmitted power (using the rf port switch and the anritsu spectrum analzyer). For accurate recording, we need to the the coupling coefficient and well as the loss in the cable from the coupler to the anritsu.
     These measurements give the coupling coefficient. The cable loss was measured separately.

Measuring the coupling coef..

   The setup:

•  Dana used the rhode & schwartz network analyzer to measure the coupling coefficients.
• For the 60 db coupler:
  
• port 1 was connected to the tx side of the coupler
• The antenna side of the coupler was terminated.
  
• port 2 was connected to the forward power coupled output
• For the 50 db coupler:
• port 1 was connected to the antenna side of the coupler
• the tx side of the coupler was terminated.
• port 2 was connected to the reverse power coupled output.
  
• Dana then swept from 5 khz to (500 MHz, 1000, or 2000 MHz )
• Measurements were made on both  coupled ports, and then averaged...
  

Plots of the coupling coefficients:

• The table below shows the plots of the coupling coefficients for the various measuremets:
  

• date	freq band	plots	freqRange of plots MHz	.s2p files
  06may15	5.125	60db fwd,50db rvs (.ps) (.pdf) black 60 db forward -61.6db at 5.125 MHz red: 50 db reverse -52.0 db at 5.125 MHz processing:x101/hf/data/cplr_150505.pro	0-500	50cplr1.s2p 50cplr2.s2p 60cplr1.s2p 60cplr2.s2p
  25may15	5.125	50 db  rvs (.ps) (.pdf) same measurement as 06may15 but extended to 2GHz -52 db and 5.125 MHz	0-2000	50cplr.s2p
  14sep16	8.175	60db fwd (.ps) (.pdf) -59.7 db at 8.175 MHz. processing: x101/160914/cplr_160914.pro	0-1000	60dbcplr1.s2p 60dbcplr2.s2p
  		need to add 60db rvs power isolation plots

  
  

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