[Elecraft] Airplane instruments issue

[jerry]

Another thing to check:  The installing agency may have skimped on the 
ground
returns.  I once installed a GNS430 com/nav/GPS in my Cessna - according 
to
the FAA guy, I was the second person to do that on the West Coast.  In 
order
to buy that unit from Garmin, I had to have an "Installing Agency".  An
avionics shop in the Midwest agreed to do that if I paid them for a 
wiring
harness.  OK, I paid them, they shipped me the harness and the radio.

I sat in front of the TV watching a movie and ohming out the whole 
harness.
I discovered that the shop had omitted many of Garmin's specified ground 
returns,
consolidating all the grounds into one or two wires.

Hey, there's a reason for all those individual returns.  I added them 
all back in.
I was rewarded by a well performing installation with no alternator 
whine.

                     - Jerry, KF6VB