[hpsdr] Noise Problem or Coincident of Generated Noise

[joetorrey at cablelynx.com]

I made a couple of changes to mySDR 1000 and Janus/Ozy setup. I also have
a second receiver (SDR IQ) sharing the same antenna as the SDR 1000.
I installed the filtering described by Ahti regarding the DC-DC converter
circuitry and when I tested this the results looked great - no issues
whatsoever.
I then removed the Janus board and installed the correction regarding the
errata/rework data; capaitors to ground from the right and left vcomm
lines on the akm ad/da chip. I tested and have a noise that raised the
noise floor some; also a noise hump that moves about at times that is
quite strong.
I also checked with the SDR IQ receiver and see it there as well; the SDR
IQ is powered up with power at the same time as the SDR 1000 is powered
up; they are tied together in the same cabinet.
The sdr IQ and sdr 1000 have been setup in this fashion for a long time. I
disconnected the antenna from between the sdr 1000 and the sdr IQ and
still see the hump but it does move in frequency.
I did reuse the capacitors that I removed from the Janus board; just
placed them correctly on the board.
I find it difficult to believe that the correctly placed Janus capacitors
could generate a noise and even get to the second receiver (sdr IQ).
Also, I am 100% sure that when the first change was made (dc-dc
converter); the test was excellent with no noise.
I am now thinking that I have an external source that generates this
noise; as I have had this before. I have ordered new capacitors (220NF)
for the Janus board just in case the heat from removall caused a short as
I did not test with an ohm meter.

Any help or insight regarding this would be much appreciated.

Thanks,
Joe
WD5Y