[DogParkList] Hammin' with my Mac issue...

[Larry West]

I'm having a problem with my Mac. It's not a problem with MacLoggerDX, 
nor the Mac itself, but with (I think) RF that's getting into the 
"shack" (in this case, basement all-purpose room).

The Mac:
Digital Audio G4 w/Sonnet 1.2Ghz processor upgrade, 1.5 gig RAM, three 
internal HDD, one external (FireWire), and DVD writer.
USB printer, mouse, keyboard, BlueTooth, iMic, iSub, PowerMate.
USB 2 PCI card installed
nVidia geForce 4 Ti digital video card.
Primary LCD monitor: Apple 15" Studio Display (ADC)
Secondary LCD Monitor: Apple 15" Studio Display (DVI - the old, 
graphite one)

HAM setup:
Icom IC-718
SEC-1223 switching power supply
MFJ-971 portable tuner
Radio & tuner are grounded to cold water pipe.
Antenna: G5RV "Junior" (51 foot, not 102) in the attic of this ranch 
house (so not too high)

The problem:

On certain bands, transmitting - even at low "tuning" power - the Mac 
will shut off if on, or may startup if off. The startup is usually 
preceded by a very loud continuous tone through the Apple Digital 
Speakers on the desk (maybe the iSub, too, but I don't know). The 
shutdown may be preceded by the Display system preference panels 
showing on the two monitors. Also, the white LEDs on the "buttons" on 
the ADC monitor may glow very brightly before either the shutdown or 
startup.

The shutdown is immediate, just like if you pressed & held the power 
button on the front of the Mac, or the ADC monitor. I am thinking that 
stray RF is making it's way along the outside of the COAX from the 
attic. I tried installing a "choke" (a short piece of coax with 5 
ferrite beads heat-shrunk to the outside of the coax) at the antenna, 
but found out that the choke I have is open for the center conductor, 
so it didn't work. I'll have to try to get another.

In the mean time, I was wondering of anyone else had similar issues, 
and how they went about solving them.

I think that if the RF isn't getting directly into the cabling, that it 
may be confusing the touchless switches on the front of the ADC 
monitor, such that it thinks you are holding your finger over it. I 
wonder if there is a way to shield them.


73,
Larry West
N2LJ
New Jersey, USA
FN20so