My ignition is an off-the-shelf full dual MSD ignition commonly used on
circle track racers that don't want to terminate a race just because of an
ignition component failure. There are two ignition modules, two coils, and
a distributer that has two magnetic pickups to trigger the ignition, one for
each ignition module. There is a switch on the panel to switch from one
ignition module and coil to the other ignition module and coil. You can't
run both ignitions at the same time. The radio noise is present with either
side. I am using Taylor 409 helical wound spark plug wires that are supposed
to be used for RF suppression. My spark plugs are resistor type NGK. All of
the headset jacks are isolated from the airframe with standard jack isolator
washers.
The problem is the same in flight and on the ground. Strobes and other
accessories don't make any difference. The pitch of the noise changes with
RPM so it is unlikely to be anything but ignition. If I unplug the antenna
wire the noise goes away so I believe it is an RF transmitted source. It is
much worse on the NAV than on the COMM for some reason. I am very well
protected from line noise with filters on power wires including very
expensive Ameri-King filters on the alternator output.
Thanks in advance to the builder's list for any information, ideas, etc.
Mike
-----Original Message-----
From:
mike.davis@dcsol.com [mailto:
mike.davis@dcsol.com] On Behalf Of
Richard Wampach
Sent: Monday, September 24, 2007 4:08 PM
To:
rebel-builders@dcsol.com
Subject: RE: [rebel-builders] Radio Noise
Mike, Am I correct to assume your noise is from ignition? Do you have a
dual ignition system? Can you switch to single, like with magnetos
left, right, off, both. Try to isolate the problem. I am sure you have
experienced the problem in flight, how about just on the ground. Try
all the combinations you can such as strobes on / off, and all other
accessories. Let us know and a whole bunch of the experts may have good
opinions on a fix!
Dick Wampach SR-108
-----Original Message-----
From:
mike.davis@dcsol.com [mailto:
mike.davis@dcsol.com] On Behalf Of
Mike Kimball
Sent: Monday, September 24, 2007 2:58 PM
To: Rebel Builder's List
Subject: [rebel-builders] Radio Noise
I've finally gotten to the point where I can fly my plane regularly now.
I
have an issue with the oil system for my gearbox. I made the mistake of
supplying oil to the gearbox from a pressurized source from the engine.
At
60-70 psi I am giving the gearbox too much volume, even through a 1/16
restriction. I lose a quart of oil in 30 minutes in flight out the
gearbox
vent. I temporarily rigged a catch can for this so I could keep flying.
I
should have taken oil from an unpressurized source (i.e., the oil pan).
I
am going to switch to a dry sump for the gearbox this winter.
Despite that, my biggest problem continues to be radio noise. Can I
enlist
the help of you other auto conversion folks? Can you tell me about your
ignition and radio setup? What kind of spark plug wires are used? Are
they
shielded? I assume your ignition is electronic HEI of some sort. Mine
has
an electronic ignition module that sends a low voltage pulse to a
standard
automotive coil which then sends the high voltage pulse through the
distributor to the spark plug. (Stock MSD stuff.) My radio is grounded
at
a grounding block that is attached to the firewall and the engine via a
large diameter grounding cable. My alternator is not the problem. I
have
run the engine with the alternator belts detached and still have the
radio
noise. I have filters on the radio power cables and the ignition module
power. Any ideas would be greatly appreciated.
Mike
-----------------------------------------------------------------
List archives located at:
https://mail.dcsol.com/login
username "rebel" password "builder"
Unsubscribe:
rebel-builders-unsubscribe@dcsol.com
List administrator:
mike.davis@dcsol.com
-----------------------------------------------------------------
-----------------------------------------------------------------
List archives located at:
https://mail.dcsol.com/login
username "rebel" password "builder"
Unsubscribe:
rebel-builders-unsubscribe@dcsol.com
List administrator:
mike.davis@dcsol.com
-----------------------------------------------------------------
-----------------------------------------------------------------
List archives located at:
https://mail.dcsol.com/login
username "rebel" password "builder"
Unsubscribe:
rebel-builders-unsubscribe@dcsol.com
List administrator:
mike.davis@dcsol.com
-----------------------------------------------------------------
