Intro

    On 11mar22 felix measured the s-parameters for the sband postamp chassis. This was after the new sband filter was installed.

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The S-parameters:

    Two sets of s parameter measurements were done:

• From sband input to postamp chassis to input to FO tx input.
• from sband input to postamp chassis to input of diplexor
• See schematic of 12meter system (.pdf)
  

    The plots show the measured s-parameters of the sband postamp chassis (.ps) (.pdf)

• colors:
• box input to FO tx input:  black=polA, red=polB
• box input to diplexor input: Green=PolA, blue=polB
• Page 1 : full scale
  
• top: s21
• 2nd: 12
• 3rd: s11
• S11 outside of the filter band is only about 3db (but the cable up to the lna has a loss of about 12db)
  
• bottom: s22
• Page 2 :blowup in freq and db
• top: s21
• The system has a gain of about 33db
  
• there is a 7.8 db difference between input to diplexor, and input to foTx inp
• there is a 7db pad and the diplexor has a loss of about .8db
• 2nd: 12
• 3rd: s11
• bottom: s22

SUMMARY:

• The sband portion of the postamp chassis has a gain of about 33db
• The sband side of the diplexor has a loss of about .8 db.

processing: x101/220311/sb_postamp_sparms.pro