[hpsdr] odd Mercury operation.

[Willi Reppel]

Hi Francis,

I noticed once an unusual raise of the noise floor.  I do not remember how many dB the  level rose but it was  much higher than usual bci or nearby arc discharges entail and I shut down my Atals/Ozi/Mercury/Penny-assembly im-mediately. The noise floor dropped back to normal after a restart. The incident happened in receive-mode and I did not bring it to the user group´s attention until how after having red your message. 

vy 73
Willi SM6OMH
  ----- Original Message ----- 
  From: FRANCIS CARCIA 
  To: hpsdr at lists.hpsdr.org 
  Sent: Monday, April 27, 2009 1:53 AM
  Subject: [hpsdr] odd Mercury operation.


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        Hi All,
        I'm noticing something new with Mercury. I would guess the input amplifier is going into oscillation. Sometimes lasts a few seconds. The broadband noise floor comes up about 50 dB. This even happens when the input is disconnected. The antenna is never connected when the radio is off and always have a 6 db pad on the input.
        I looked at the board under a microscope looking for bad connections and also replaced the bad input relay. It hit almost 90 today so was motivated to solder a loop of copper tube to the heatsink pad undder the A/D.  It also runs pretty hot. 
        Anyone ever notice this raise in noise floor? 
        The power supply is a linear. Frank WA1GFZ 



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