[hpsdr] phase noise

[FRANCIS CARCIA]

I find it interesting to monitor phase noise with the flex display. The level does not change with bandwidth. Many articles I have read take a correction factor for the bandwidth of the monitor device, log BW hz improving the phase noise. This is broadband noise and my hours sitting behind the old NF102 doing MIL-STD 461A testing has me wondering if this correction can be taken for a broadband  signal. When we changed bandwidths on the old NF102 a BB signal would not change amplitude while a narrow band signal would. When I run the phase noise test per ARRL method the result follows the uncorrected value not the lower assumed value. This also tracks the degraded dynamic range on close in signals. 
  Even the Russian guy who had an article in QEX used a 1 KHz filter to measure his phase noise so he took 30 dB. I'm considering going back to my homebrew RX and ripping out the synthesizer and installing an HP8640B cavity because that is the closest thing I see to a crystal oscillator. Yes a DDS is clean close in at the expense of bb spurs.
  Any smart guy want to set me straight here. Frank WA1GFZ
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