Today's Message Index:
----------------------
1. 06:45 AM - Re: Request for some direction and advise (Eric M. Jones)
2. 10:54 AM - Re: Re: Request for some direction and advise (Robert L. Nuckolls, III)
3. 11:44 AM - Tesla Meter App and Magnetism (Don Johnson)
4. 01:42 PM - Re: Re: Request for some direction and advise (C&K)
5. 05:43 PM - Re: Tesla Meter App and Magnetism (user9253)
6. 06:43 PM - Re: Re: Tesla Meter App and Magnetism (Charlie England)
7. 06:45 PM - Re: Re: Tesla Meter App and Magnetism (Charlie England)
8. 08:01 PM - Re: Tesla Meter App and Magnetism (user9253)
9. 09:04 PM - Re: Re: Tesla Meter App and Magnetism (Tim Olson)
10. 09:31 PM - Re: Re: Request for some direction and advise (Bill Bradburry)
11. 09:38 PM - Re: Re: Tesla Meter App and Magnetism (Jim Kale)
Message 1
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Subject: | Re: Request for some direction and advise |
My Father (who worked on Westinghouse's part of the USN Vanguard rocket), related
to me the ultimate failure with it:
Test techs would unplug all the tubes (yes it had tubes) test the tubes and stick
them back into their sockets....time after time after time. (One thinks they
must also have unplugged every module too).
So everything tested fine, and when the rocket took off, all the vibration caused
the tube sockets to quit making contact because they were worn out.
Whether or not this was entirely true, the lesson remains: Contacts are the first
place to look for most sorts of electrical problems. For the remainder, contacts
probably had something to do with the failure in the first place.
Contact failure can occur in ways you would never suspect. In the medical field
people get shocked because the plating has worn off brass contacts, which now
behave as diodes. The HF used in surgery ("Bovies") now generates HV DC instead
of the HF AC used in electrosurgery. OUCH!
So always suspect connections first. Both intended and unintended.
--------
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=446683#446683
Message 2
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Subject: | RE: Request for some direction and advise |
>One other thing that I just thought of that may be a factor. The
>backing plate through connectors that the radio slides into when it
>is inserted into the tray are very wobbly. It is very easy to make
>a circle with them that is at least 1/8 inch in radius. I have
>never thought about these connectors before because I thought that
>they were wobbly in order to line up with the radio when in is
>inserted. But now thinking about it, it seems to me that they
>should firm up when the radio is inserted because they are making
>rigid contact with the radio?? Mine are still wobbly after the
>radio is inserted. Could these connectors or the backing plate be
>somehow incorrectly installed?
Tray connectors often 'float' on the tray
itself so as to accommodate dimenational differences
between tray and radio as the radio is slid into
the tray. Similarly, your antenna connectors
a the back of the radio may appear 'loose' in
spite of having perfect electrical integrity.
http://tinyurl.com/qa5hr7l
In the image sited above, we see where electrical
integrity is achieved as a separate component
of mechanical mounting. A BNC connector attached
to an appliance.
http://tinyurl.com/pmy4hsg
In the video above, we see that a connector is
"loose" to move in some regard while mantaining
electrical integrity of the connection.
>
>Does anyone know if these connectors should be firm after the radio
>is installed? Could this be where I have a bad connection with the shield?
The connections I am most concerned about are
between the coax shield and it's terminating
connector.
>
>What about the other shield grounds described below? Would they be
>a factor if that card edge connector does not make a firm
>connection? There is a boss just to the side of this card edge
>connector that I am considering using to run a separate ground wire
>from the backing plate to the "forest of tabs" ground block. Are
>there any opinions on this idea?
Your symptoms scream of antagonistic disruption of
TWO different systems that suggest
a problem with the level of RF in the cockpit
due to an antenna system problem . . . not with
the radio's power/signal wires.
Bob . . .
Message 3
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Subject: | Tesla Meter App and Magnetism |
About a year ago when flying my RV-9A to Air Venture, I noticed after
departing a small airport in Ohio and preparing to fly over Lake
Michigan,
that my vertical card compass was stuck on 230 degrees. I used the GPS
heading to reorient my DG and went on my way=85
Upon returning home, I decided to replace that compass with one mounted
on
the center support to the roll bar. Same problem ' stuck on 230
degrees +
or ' 10 degrees.
Now in the middle of upgrading from steam gauges to Dynon 180, etc., I
ran
across an Iphone App called Tesla Meter on the App store. There are at
least 10 similar apps that point to a source of magnetism and give a
strength reading in a measurement referred to as =B5T. Moving it around
the
cockpit, the signal was very strong and pointed to the junction of the
roll
bar and fuselage ' readings of approximately 500 =B5T on the both the
left and
right junctions of the fuselage and the roll bar. The remainder of the
roll
bar and the support showed readings of 60 to 70 =B5T. While I was at
it, I
checked other steel pieces around the plane and found two bars on the
motor
mount with readings in the 400+ =B5T range.
Knowing this group is far more informed than I am, I pose the following
questions:
1. Is the high reading at the mounting points of the roll bar the
likely cause of the stuck compass?
2. Can you offer an explanation as the why those areas show a high
reading?
3. If those areas are the problem, how do I correct it?
Thanks for your help.
Don Johnson
RV-9A
Message 4
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Subject: | Re: Request for some direction and advise |
I love this story Eric
Of course I just spent two days tracking a glitch that turned out to be
a poor digital signal connection in a good looking shiny solder joint...
Ken
do not archive
On 02/09/2015 9:43 AM, Eric M. Jones wrote:
>
> My Father (who worked on Westinghouse's part of the USN Vanguard rocket), related
to me the ultimate failure with it:
>
> Test techs would unplug all the tubes (yes it had tubes) test the tubes and stick
them back into their sockets....time after time after time. (One thinks they
must also have unplugged every module too).
>
> So everything tested fine, and when the rocket took off, all the vibration caused
the tube sockets to quit making contact because they were worn out.
>
> Whether or not this was entirely true, the lesson remains: Contacts are the first
place to look for most sorts of electrical problems. For the remainder, contacts
probably had something to do with the failure in the first place.
>
> Contact failure can occur in ways you would never suspect. In the medical field
people get shocked because the plating has worn off brass contacts, which now
behave as diodes. The HF used in surgery ("Bovies") now generates HV DC instead
of the HF AC used in electrosurgery. OUCH!
>
> So always suspect connections first. Both intended and unintended.
>
> --------
> Eric M. Jones
> www.PerihelionDesign.com
> 113 Brentwood Drive
> Southbridge, MA 01550
> (508) 764-2072
> emjones(at)charter.net
>
>
Message 5
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Subject: | Re: Tesla Meter App and Magnetism |
I have not actually tried this but a knowledgeable person told me that a soldering
gun (NOT iron) can be used to demagnetize steel. The object to be demagnetized
is passed through the soldering gun heating element loop while the gun trigger
is pulled. Of course an airframe is too big, but maybe the soldering gun
heating element can be removed from the gun, then placed around the steel tube,
then connected back onto the soldering gun. Then the soldering gun trigger
is pulled while moving the gun back and forth along the steel tube.
If that is not feasible, then maybe someone else knows how to make a demagnetizer
using the same principle.
Here is a youtube movie about making a demagnetizer:
https://www.youtube.com/watch?v=8kKTJQTyX-w
Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=446707#446707
Message 6
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Subject: | Re: Tesla Meter App and Magnetism |
On 9/2/2015 7:41 PM, user9253 wrote:
>
> I have not actually tried this but a knowledgeable person told me that a soldering
gun (NOT iron) can be used to demagnetize steel. The object to be demagnetized
is passed through the soldering gun heating element loop while the gun
trigger is pulled. Of course an airframe is too big, but maybe the soldering
gun heating element can be removed from the gun, then placed around the steel
tube, then connected back onto the soldering gun. Then the soldering gun trigger
is pulled while moving the gun back and forth along the steel tube.
> If that is not feasible, then maybe someone else knows how to make a demagnetizer
using the same principle.
> Here is a youtube movie about making a demagnetizer:
> https://www.youtube.com/watch?v=8kKTJQTyX-w
> Joe
>
> --------
> Joe Gores
Find a TV repair shop that's been around since before flat screens (tube
type days). Ask if they still have their degaussing coil (mine's still
packed away somewhere, after closing the shop 20 years ago).
Message 7
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Subject: | Re: Tesla Meter App and Magnetism |
On 9/2/2015 7:41 PM, user9253 wrote:
>
> I have not actually tried this but a knowledgeable person told me that a soldering
gun (NOT iron) can be used to demagnetize steel. The object to be demagnetized
is passed through the soldering gun heating element loop while the gun
trigger is pulled. Of course an airframe is too big, but maybe the soldering
gun heating element can be removed from the gun, then placed around the steel
tube, then connected back onto the soldering gun. Then the soldering gun trigger
is pulled while moving the gun back and forth along the steel tube.
> If that is not feasible, then maybe someone else knows how to make a demagnetizer
using the same principle.
> Here is a youtube movie about making a demagnetizer:
> https://www.youtube.com/watch?v=8kKTJQTyX-w
> Joe
>
> --------
> Joe Gores
>
>
Add to my previous post: don't forget to remove the compass & anything
else that might get trashed by a big magnetic field (AHARS units,
magnetometers, etc).
Message 8
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Subject: | Re: Tesla Meter App and Magnetism |
Found this on the internet about demagnetizing:
> What if you could put many wraps of insulated wire around the pipe and connect
an AC welder to the wire. The longer the wire the better and of course the wire
will have to handle the amps you feed it with the welder. Move the coil of
wire down the length of the pipe. Don't see why this wouldn't work. LOL George
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=446710#446710
Message 9
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Subject: | Re: Tesla Meter App and Magnetism |
I would suggest also posting to the RV list. I don't know a lot about
it but
a few years ago I read many posts regarding degaussing canopy frames.
I think the people built their own degaussers even, perhaps. I guess a lot
of the RV's with metal frames had some residual magnetism and people would
degauss them and get them back to much less magnetic.
Also, maybe try searching the matronics archive via the web login.
Tim
On 9/2/2015 7:41 PM, user9253 wrote:
>
> I have not actually tried this but a knowledgeable person told me that a soldering
gun (NOT iron) can be used to demagnetize steel. The object to be demagnetized
is passed through the soldering gun heating element loop while the gun
trigger is pulled. Of course an airframe is too big, but maybe the soldering
gun heating element can be removed from the gun, then placed around the steel
tube, then connected back onto the soldering gun. Then the soldering gun trigger
is pulled while moving the gun back and forth along the steel tube.
> If that is not feasible, then maybe someone else knows how to make a demagnetizer
using the same principle.
> Here is a youtube movie about making a demagnetizer:
> https://www.youtube.com/watch?v=8kKTJQTyX-w
> Joe
>
> --------
> Joe Gores
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=446707#446707
>
Message 10
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Subject: | RE: Request for some direction and advise |
Bob,
Success!
I thank you for sending me in the proper direction to find this problem.
I
would never have figured out that it was RF loose in the cockpit. While
I
was checking for where I could possibly have a loose connection this
afternoon, I removed the radio from the tray and measured both the
length of
the radio and the distance it had to reach to the connectors in the back
plate. Whoops! Looks like the radio needs to be seated deeper into the
tray!
Stupid builder tricks! When I installed the radio, I installed a bezel
around them and to make it look nicer, I put the bezel under the
faceplate
on the radio. The radio passed the test Garmin has for that, (three
turns of
the screw after the radio powers on) but apparently over time it got
looser
and looser and started having more and more symptoms. I modified the
bezel
this afternoon so the radio would properly seat and the problem appears
to
have resolved. I was getting a huge RF leak from the back of the radio
prior to it getting into the coax.
I am completing my conditional inspection so it will be a few days
before I
can fly and see just what symptoms I have fixed.
Thanks, Bob!
Bill
_____
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
Robert L.
Nuckolls, III
Sent: Wednesday, September 02, 2015 12:53 PM
Subject: RE: AeroElectric-List: RE: Request for some direction and
advise
One other thing that I just thought of that may be a factor. The
backing
plate through connectors that the radio slides into when it is inserted
into
the tray are very wobbly. It is very easy to make a circle with them
that
is at least 1/8 inch in radius. I have never thought about these
connectors
before because I thought that they were wobbly in order to line up with
the
radio when in is inserted. But now thinking about it, it seems to me
that
they should firm up when the radio is inserted because they are making
rigid
contact with the radio?? Mine are still wobbly after the radio is
inserted.
Could these connectors or the backing plate be somehow incorrectly
installed?
Tray connectors often 'float' on the tray
itself so as to accommodate dimenational differences
between tray and radio as the radio is slid into
the tray. Similarly, your antenna connectors
a the back of the radio may appear 'loose' in
spite of having perfect electrical integrity.
http://tinyurl.com/qa5hr7l
In the image sited above, we see where electrical
integrity is achieved as a separate component
of mechanical mounting. A BNC connector attached
to an appliance.
http://tinyurl.com/pmy4hsg
In the video above, we see that a connector is
"loose" to move in some regard while mantaining
electrical integrity of the connection.
Does anyone know if these connectors should be firm after the radio is
installed? Could this be where I have a bad connection with the shield?
The connections I am most concerned about are
between the coax shield and it's terminating
connector.
What about the other shield grounds described below? Would they be a
factor
if that card edge connector does not make a firm connection? There is a
boss just to the side of this card edge connector that I am considering
using to run a separate ground wire from the backing plate to the
=13forest of
tabs=14 ground block. Are there any opinions on this idea?
Your symptoms scream of antagonistic disruption of
TWO different systems that suggest
a problem with the level of RF in the cockpit
due to an antenna system problem . . . not with
the radio's power/signal wires.
Bob . . .
Message 11
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Subject: | Re: Tesla Meter App and Magnetism |
Way back when TVs had large Picture Tubes, more properly called cathode ray
tubes, technicians had coils of wire plugged into 110 volt AC. They waved
them all over the television metal chassis. This alternating magnetic field
demagnetized the TV. Also called degaussing. Magnetic fields on the TV
Chassis would distort the picture. This system could also be used on the
metal parts of an airplane. However, if you don't know what you are doing,
you could easily demagnetize some parts that need their magnetic fields to
operate properly. Yes, like the compass, but possibly also some delicate
and expensive avionics. Let the experimenter beware!!
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Charlie
England
Sent: Wednesday, September 2, 2015 8:45 PM
Subject: Re: AeroElectric-List: Re: Tesla Meter App and Magnetism
--> <ceengland7@gmail.com>
On 9/2/2015 7:41 PM, user9253 wrote:
> --> <fransew@gmail.com>
>
> I have not actually tried this but a knowledgeable person told me that a
soldering gun (NOT iron) can be used to demagnetize steel. The object to be
demagnetized is passed through the soldering gun heating element loop while
the gun trigger is pulled. Of course an airframe is too big, but maybe the
soldering gun heating element can be removed from the gun, then placed
around the steel tube, then connected back onto the soldering gun. Then the
soldering gun trigger is pulled while moving the gun back and forth along
the steel tube.
> If that is not feasible, then maybe someone else knows how to make a
demagnetizer using the same principle.
> Here is a youtube movie about making a demagnetizer:
> https://www.youtube.com/watch?v=8kKTJQTyX-w
> Joe
>
> --------
> Joe Gores
Find a TV repair shop that's been around since before flat screens (tube
type days). Ask if they still have their degaussing coil (mine's still
packed away somewhere, after closing the shop 20 years ago).
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