Intro

    On  31sep21 felix measured the spectrum of the 12meter miteq xb amplifier in the lab using the hp E4445A spectrum analyzer.
The amp had a 50 ohm terminator at its input (using the waveguide transition).

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Plots

The  plot shows the measured data (.ps) (.pdf):

• Page 1: spectra in the lab
  
• The resolution bandwidth(rbw) was 300KHz
• Top: the measured spectra
• bottom: divide by the rbw and the 300K of the input resistor to get the gain.
• We use the amp between 8050 and 9200 Mhz
  
• Page 2: compare lna output with 50 ohm load and antenna on input.
• black:the spectra measured with a 50 ohm load on input
• red: the spectra measured with 12m as input to the amp
• see lna output with telescope as input

Summary:

• the plots show the output of the miteq lna with a 50 ohm load on the input.
• Comparing the outputs with a 50 ohm load input and the telescope input
• The two spectra are similar in the 8050 to 9200 Mhz range where we use the amp.
• The low freq part of the band differs by up to 25 db.
• The large amount of power in the 4-8 Ghz  range when on the telescope is cutting down on the dynamic range of the system.
  

processing: x101/21031/xblnagain.pro