Here is the authority on the issue. http://audiosystemsgroup.com/RFI-Ham.pdf
Have you put ferrite on the cables from the iMac and the switching power
supply?
You've used "star" grounding around the KX3. Try bonding everything to
everything - you want to provide a low-impedance parallel path from case
to case everywhere there is a connection. So, there should be a bond
between the soundcard and the iMac and the soundcard and power supply.
Also the iMac and soundcard to the PX3. Your diagram should look more
like a spider web.
Are the interconnecting cables grounded to the chassis or the circuit
board? You'll have to open some things up and see if there is the "pin
1 problem" where the cable's ground is on the circuit board and not the
chassis.
I would look for a YouTube video on how to open up that iMac. I am sure
someone has posted one.
K4ia
Buck
Honor Roll 335
8BDXCC
On 6/5/2016 8:03 AM, Joel Black wrote:
I figured out most of my problems with all the spikes on the PX3 - the
switching P/S in my iMac. To a lesser extent, I can hear the MFJ-4125 switching
P/S I use to power the KX3 and PX3. I cannot remember if I tried looking at the
spectrum using the Astron RS-35 as a power source and plugging in the 4125 or
not. I will try that today. I did use the RX SHFT and was able to move a huge
spike off the carrier. Does RX SHFT still nullify the roofing filter or was
that fixed in a F/W update?
I’m pretty sure I can bond the KX3, PX3, and MFJ-4125 but I don’t have a *clue*
how to bond the iMac. It’s a late 2012 27” iMac. It’s an all-in-one with *no*
external screws. It’s the model with the “pregnant” bulge in the back. However,
if it means I have to go to a Windows computer, I’ll live with the noise or
build a Hackintosh. I also use this computer for other things - editing video,
etc.
I *did* try my wife’s Mac Book Pro with the power supply plugged in and I did
not notice the P/S noise on the PX3; however, her computer is not powerful
enough to edit video unless you have time to wait. ;)
Just to make sure I understand what I need to do:
1. Bond the KX3 to the power supply.
2. Bond the KX3 to the PX3.
3. Bond the KX3 to the computer (somehow).
4. Bond the KX3 to the sound card (in my case, a Focusrite 2i2).
Trying to use ASCII to draw, I’m guessing it should look like this:
PX3————KX3———MFJ-4125
/ \
/ \
iMac Focusrite 2i2
My KX3 antenna connection goes to a 4-way switch to switch between my OCF,
NVIS, vertical, and dummy load. Does the KX3 need to be bonded to that as well?
All of the feed lines run up through the wall, into the attic, and out a soffit
vent to surge protectors attached to a ground rod. That ground rod is bonded to
house ground. The OCF and the NVIS are on a fiberglass pole in the middle of
the back yard. There is no ground rod there. The vertical is over to the side
and is bonded to a ground rod there. That ground rod is not bonded but, from my
reading, it should be.
Does this look/sound right? Please be critical. I cannot learn unless you tell
me where I screwed up. I have pretty thick skin. ;)
73,
Joel - W4JBB
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