Today's Message Index:
----------------------
1. 03:59 AM - Re: Help needed: continued strobe noise & weak radio (FLYaDIVE@aol.com)
2. 05:54 AM - Re: Re: Electric failure (Brian Lloyd)
3. 05:55 AM - Re: Re: Electric failure (Hopperdhh@aol.com)
4. 06:02 AM - XM Radio with Garmin 530/430? (Paul Weismann)
5. 06:20 AM - Re: XM Radio with Garmin 530/430? (Bill Denton)
6. 06:39 AM - Re: Re: Electric failure (Robert L. Nuckolls, III)
7. 07:20 AM - Re: Help needed: continued strobe noise & weak radio (Brian Lloyd)
8. 07:21 AM - Re: Re: Electric failure (Brian Lloyd)
9. 07:35 AM - magnetic shielding (Brian Lloyd)
10. 08:06 AM - Re: Drop-out relay (John Burnaby)
11. 08:27 AM - Re: Re: Electric failure (Werner Schneider)
12. 08:40 AM - Re: Drop-out relay (Brian Lloyd)
13. 08:43 AM - Re: Re: Electric failure (SteinAir, Inc.)
14. 08:43 AM - Re: Drop-out relay (Mark R Steitle)
15. 08:48 AM - Re: Drop-out relay (Konrad L. Werner)
16. 08:57 AM - Re: Re: Electric failure (Brian Lloyd)
17. 09:30 AM - Re: electric failure (Erich_Weaver@URSCorp.com)
18. 09:43 AM - Re: Drop-out relay (Fiveonepw@aol.com)
19. 09:45 AM - Re: Drop-out relay (Fiveonepw@aol.com)
20. 09:55 AM - Re: Help needed: continued strobe noise & weak radio (Carlos Trigo)
21. 10:29 AM - Re: Help needed: continued strobe noise & weak radio (Jerry Grimmonpre)
22. 12:00 PM - Re: Help needed: continued strobe noise & weak radio (Brian Lloyd)
23. 12:03 PM - Re: Help needed: continued strobe noise & weak radio (Brian Lloyd)
24. 12:35 PM - Re: Help needed: continued strobe noise & weak (Earl_Schroeder)
25. 01:44 PM - Electric failure (glen matejcek)
26. 04:07 PM - Re: Re: Electric failure (Paul McAllister)
27. 07:38 PM - Re: Electric failure (Jeffery J. Morgan)
28. 09:01 PM - SD-8 ALTERNATOR MOD FOR SELF EXCITATION (Robert L. Nuckolls, III)
29. 09:24 PM - Re: Re: Electric failure (Robert L. Nuckolls, III)
30. 10:23 PM - Re: SD-8 ALTERNATOR MOD FOR SELF EXCITATION (Bob McCallum)
Message 1
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Subject: | Re: Help needed: continued strobe noise & weak radio |
In a message dated 7/17/2006 7:59:52 AM Eastern Standard Time,
brian-yak@lloyd.com writes:
>> Lucky: I used Van's pre-made wiring kit but I don't recall if the
>> wiring
> to
>> the strobes was shielded or not.
> =====================================
> Lucky:
>
> I think you found the problem. I say that because of the above
> statement about the pre-made harness. If they are running the strobe's
wires
> right along side the wires for your other lights AND if they are not
shielded
> then it would be very easy for the other wires to pick up the noise from
the
> strobes.
> Try running a separate SHIELDED pair of wires and ground the shield
> ONLY at the strobe. The shielded pair should have three wires ... B+. Neg
> and SHIELD.
> The Neg is grounded at both ends, while the shield is only at the
> strobe. I would still use the filter, just for S&Gs. Run the strobe
wires
> away from the other wires.
Barry, you keep making statements like this but I am not sure you
have really thought through what you are saying.
When you run two wires in parallel there are two coupling modes:
capacitive and inductive. When impedances are very high (it is
difficult to get current to flow) then capacitive coupling dominates.
When impedances are very low, as in power circuits, coupling is
inductive, with the current in one wire inducing a current in the
other wire by magnetic (inductive) coupling.
Brian:
I make these statements because I know they work.
As for Inductive / capacitive coupling. We are talking DC circuits with
Noise in the AUDIO frequency range.
As the saying goes: K.I.S.S. M.E. All this stuff about capacitive and
inductive coupling is not an issue in a simple noise problem as we are discussing
here. AND what the heck is "NON-MAGNETIC BRAID-TYPE SHIELDING"? Do you really
expect people to go out looking for "mu-metal"? ALL the braid used on any
electrical circuit on our planes is NONMAGNETIC ... It is made of COPPER WIRE.
Copper is non magnetic the last time I checked. Again K.I.S.S. M.E. is the word
of the day.
Electronics is simple, it is really! All these boog-a-boo statements only
confuses the non-electrical types amongst us. The only thing they need to know
is how to remove the noise. Again that goes back to the basics of noise, and
breaking it down into DC and AC ... AC goes one step further (Audio
Frequencies [AF] and Radio Frequencies [RF]).
Basics:
AF Noise - Shield and Ground at the source [This is why the Mic & Phone lines
use insulating washers at the jacks and ground at the audio panel or radios.]
RF Noise - Shield and Ground at both ends. [Here is where exceptions come
into play - Some times the grounding is done through a capacitor. BUT we are
dealing with AF Noise not RF so I'm not going to try to confuse people out
there.]
Let the manufacture of the wire worry about resistance of 1000 Ft and the
capacitive coupling / inductive coupling at AF & RF. The ONLY thing that would
be of interest to our noise plagued brevien is the Percentage of Braid. You
did not say anything about that! Yet again as long as you use Mil-Spec wire the
percentage of braid is acceptable and again our brevien does not have to be
concerned.
As for the Separation of wires .... I did address that with my very first
statement to Lucky; read above.
I would suggest that all the AF noise (strobe noise) we are discussing be
approached as I described AND then if the noise still exists just add another
ground t=at the other end of the shield. It is MUCH easier to ADD a ground than
to remove a ground.
Barry
"Chop'd Liver"
=============================================================================
===
The problem with non-magnetic braid-type shielding is that it does
almost nothing for inductive coupling. The magnetic lines of force go
right through the shielding and induce currents in the shielded
conductor just as if the shield wasn't there. That is why shielding
on the alternator 'B' lead is useless to reduce noise. So you aren't
going to fix noise from your strobe power supply getting into your
other power wiring with a nonmagnetic shielding braid.
BTW, a shielding braid grounded at only one end is an electrostatic
shield and only works to reduce capacitive coupling.
If the problem is inductive coupling between wires there are only two
solutions:
1. separation;
2. the use of a magnetic shielding material like mu-metal.
If you have a severe inductive coupling problem and you can't get
separation you can get magnetic shielding braid and sheets to help
fix the problem. I used that to solve a problem with the motor in my
T&B affecting my compass in my RV-4.
Brian Lloyd 361 Catterline Way
brian-yak AT lloyd DOT com Folsom, CA 95630
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
Message 2
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Subject: | Re: Electric failure |
--> AeroElectric-List message posted by: Brian Lloyd <brian-yak@lloyd.com>
On Jul 18, 2006, at 10:00 PM, Robert L. Nuckolls, III wrote:
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
> <nuckollsr@cox.net>
>
>
>>> How about a gps aided wing leveler that is independent of
>>> all other goodies on the panel? Perhaps DUAL wing levelers.
>>
>> Oh, no doubt it can be done. It is just that I am realizing that all
>> this complexity is not meeting the promise of reduced cockpit
>> workload.
>
> As long as any operating mode requires a human to observe,
> and interpret displays, and react in the appropriate controls
> inputs to aviate, then there is nothing anyone can do with either
> brass or glass to "reduce cockpit workload". Who ever is promising
> lower workloads while leaving the pilot in the loop is blowing
> lots of smoke you-know-where.
Oh, it is quite possible for automation to lower cockpit workload. As
you point out, automation does a great job of tirelessly watching
things and making mindless corrections. Your wing-leveler is a good
point. Engine instrumentation is good too. How annoying is it to
realize that you got distracted and only just looked up to see that
the oil pressure is approaching zero and oil temp is well up past red
line. Much better to have that mindless servant bring it to your
attention than to depend on you remembering to scan the engine gauges.
Part of the problem is the user interface. Most GPS and FMS have
confusing, inflexible interfaces with the human that don't permit
easy changes. The point I was making is that it is a LOT easier to
dial a new frequency into a VOR receiver and then reach up to turn an
OBS to center the CDI, look at the new bearing/radial, and turn the
airplane to a new heading than it is to reprogram even a simple
flight plan in a GPS.
I was just musing aloud on my recent flying (I have racked up 50
hours of international cross-country flight in the last month). I am
finding myself back on the victor airways and using my VORs almost as
much as my GPS. (The GPS gives me ground track information which
helps me do a much better job of adhering to to my desired track than
does the trial-and-error approach of VOR.) I use my charts to decide
where I am going to go so the GPS is no longer absolutely dominant in
my navigation. Navigation automation is not necessarily better under
all conditions.
> We used to EXPECT a pilot to belly up to that bar with
> the aplomb of Lindbergh and the daring-do of a WWI flying
> ace and show us how a "real pilot" does it.
Don't forget panache. :-)
> But it's an inarguable, simple-idea that nobody keeps
> the wings level tirelessly and more accurately than
> a rate gyro, a handful of jelly bean parts and a servo motor.
> Add some GPS data and you've got a fantastic recipe for
> success. When the bill of materials and lines of software
> to do the task are 1/10th that of a panel mounted display
> (that depends on the eyeball-brain-hand interface)
> I can see no better cost benefit ratio or more elegant
> solution for lower complexity. And guess what? It absolutely
> guarantees and demonstrates lower cockpit workload.
No argument there.
Brian Lloyd 361 Catterline Way
brian-yak AT lloyd DOT com Folsom, CA 95630
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
I fly because it releases my mind from the tyranny of petty things . . .
Antoine de Saint-Exupry
Message 3
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Subject: | Re: Electric failure |
In a message dated 7/19/2006 1:24:51 A.M. Eastern Daylight Time,
bnn@nethere.com writes:
At 07:00 PM 7/18/2006, you wrote:
> But it's an inarguable, simple-idea that nobody keeps
> the wings level tirelessly and more accurately than
> a rate gyro, a handful of jelly bean parts and a servo motor.
> Add some GPS data and you've got a fantastic recipe for
> success. When the bill of materials and lines of software
> to do the task are 1/10th that of a panel mounted display
> (that depends on the eyeball-brain-hand interface)
> I can see no better cost benefit ratio or more elegant
> solution for lower complexity. And guess what? It absolutely
> guarantees and demonstrates lower cockpit workload.
Not being smart. Just wondering. Does this exist? If not, why not? If so,
who does it?
Thanks,
Guy Buchanan
K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar.
This sounds a lot like my Garmin GPS295 and my Navaid autopilot.
Dan Hopper
RV-7A
Message 4
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Subject: | XM Radio with Garmin 530/430? |
I have installed a GDL-69A Satellite Weather/XM Radio unit in my
aircraft and I have the Garmin 530/430 setup.
The current software of the 530/430 does not allow for the display of XM
Radio information on the units' screens. There is no way to know what
channel you're on or any of the other information XM usually sends out
over the signal such as song name etc. Apparently, this issue will be
addressed in Garmin's long delayed WAAS Upgrade where the units have to
be factory upgraded.
My local avionics tech who helped me with the install says the GDL unit
requires discreet switch "toggles" to switch channels, so we put a
rocker switch in the panel and for each click up or down, the channel
goes up or down. My first question is, is there a ROTARY switch that
can accomplish this discreet single point signal? If I am being unclear
please let me know as I am not sure of the precise terminology.
My second question is, has anyone figured out a way to use a commercial
Roadie or other XM Radio display unit as a display for their GDL
installation? I would love to be able to use the Roadie channel knob
and be able to view channel info on a display.
Thanks in advance.
Paul
Message 5
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Subject: | XM Radio with Garmin 530/430? |
Couple of things...
Where did you get the information that the 430/530 will eventually control
GDL-69A XM Radio?
And whatever might happen in the future, wouldn't the simplest short-term
solution be to simply tie the XM Roadie into your audio panel?
-----Original Message-----
[mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Paul
Weismann
Sent: Wednesday, July 19, 2006 7:59 AM
I have installed a GDL-69A Satellite Weather/XM Radio unit in my aircraft
and I have the Garmin 530/430 setup.
The current software of the 530/430 does not allow for the display of XM
Radio information on the units' screens. There is no way to know what
channel you're on or any of the other information XM usually sends out over
the signal such as song name etc. Apparently, this issue will be addressed
in Garmin's long delayed WAAS Upgrade where the units have to be factory
upgraded.
My local avionics tech who helped me with the install says the GDL unit
requires discreet switch "toggles" to switch channels, so we put a rocker
switch in the panel and for each click up or down, the channel goes up or
down. My first question is, is there a ROTARY switch that can accomplish
this discreet single point signal? If I am being unclear please let me know
as I am not sure of the precise terminology.
My second question is, has anyone figured out a way to use a commercial
Roadie or other XM Radio display unit as a display for their GDL
installation? I would love to be able to use the Roadie channel knob and be
able to view channel info on a display.
Thanks in advance.
Paul
Message 6
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Subject: | Re: Electric failure |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 10:05 PM 7/18/2006 -0700, you wrote:
>--> AeroElectric-List message posted by: Guy Buchanan <bnn@nethere.com>
>
>At 07:00 PM 7/18/2006, you wrote:
>> But it's an inarguable, simple-idea that nobody keeps
>> the wings level tirelessly and more accurately than
>> a rate gyro, a handful of jelly bean parts and a servo motor.
>> Add some GPS data and you've got a fantastic recipe for
>> success. When the bill of materials and lines of software
>> to do the task are 1/10th that of a panel mounted display
>> (that depends on the eyeball-brain-hand interface)
>> I can see no better cost benefit ratio or more elegant
>> solution for lower complexity. And guess what? It absolutely
>> guarantees and demonstrates lower cockpit workload.
>
>Not being smart. Just wondering. Does this exist? If not, why not? If so,
>who does it?
If anyone is close right now, it's Jim Younkin at
TruTrak. I've had the core components of a design
on the back burner for years and things really took
a turn toward realization when Analog Devices finally
slew the dragons for manufacturing an inexpensive, solid
state rotation rate sensor. See:
http://www.analog.com/en/prod/0%2C2877%2CADXRS401%2C00.html
GPS engines are becomming jelly bean parts too. See:
http://www.rfsolutions.co.uk/acatalog/Embedded_GPS_Module.html
The hardware is a no-brainer. Development of a manufacturable
product takes $time$ and ultimately an airplane . . . both
of which are in my "pretty-hard" pile. But I'm still watching
for opportunities to consider an entry into this market.
Jim would be a most worthy competitor.
Bob . . .
---------------------------------------------------------
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
---------------------------------------------------------
Message 7
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Subject: | Re: Help needed: continued strobe noise & weak radio |
--> AeroElectric-List message posted by: Brian Lloyd <brian-yak@lloyd.com>
On Jul 19, 2006, at 6:49 AM, FLYaDIVE@aol.com wrote:
> Barry, you keep making statements like this but I am not sure you
> have really thought through what you are saying.
>
> When you run two wires in parallel there are two coupling modes:
> capacitive and inductive. When impedances are very high (it is
> difficult to get current to flow) then capacitive coupling dominates.
> When impedances are very low, as in power circuits, coupling is
> inductive, with the current in one wire inducing a current in the
> other wire by magnetic (inductive) coupling.
>
> Brian:
>
> I make these statements because I know they work.
Copper braid or foil shield does not work to reduce inductive
coupling between wires in low-impedance circuits at audio frequencies.
> As for Inductive / capacitive coupling. We are talking DC circuits
> with Noise in the AUDIO frequency range.
Right.
> As the saying goes: K.I.S.S. M.E. All this stuff about capacitive
> and inductive coupling is not an issue in a simple noise problem as
> we are discussing here.
Actually, it is.
> AND what the heck is "NON-MAGNETIC BRAID-TYPE SHIELDING"? Do you
> really expect people to go out looking for "mu-metal"?
Yes, if that is the problem they are trying to solve.
> ALL the braid used on any electrical circuit on our planes is
> NONMAGNETIC ... It is made of COPPER WIRE. Copper is non magnetic
> the last time I checked. Again K.I.S.S. M.E. is the word of the day.
But Barry, it isn't going to work in this application. There are
magnetic shielding braids that are available. They look a bit like
stainless steel braid and they work WONDERS for eliminating DC and
audio effects on conductors carrying significant currents.
> Electronics is simple, it is really!
Well, like most things, it is simple if you understand it and have
worked with it. It is not simple if you are ignorant of the
principles. (And ignorance is not a bad thing as it can be remedied
by education. It is only a bad thing if one chooses to remain ignorant.)
> All these boog-a-boo statements only confuses the non-electrical
> types amongst us.
Confusion is eliminated through education. I happen to believe that
anyone smart enough to successfully build an airplane is smart enough
to learn and understand some basic electrical principles.
> The only thing they need to know is how to remove the noise. Again
> that goes back to the basics of noise, and breaking it down into DC
> and AC ... AC goes one step further (Audio Frequencies [AF] and
> Radio Frequencies [RF]).
> Basics:
> AF Noise - Shield and Ground at the source [This is why the Mic &
> Phone lines use insulating washers at the jacks and ground at the
> audio panel or radios.]
> RF Noise - Shield and Ground at both ends. [Here is where
> exceptions come into play - Some times the grounding is done
> through a capacitor. BUT we are dealing with AF Noise not RF so I'm
> not going to try to confuse people out there.]
Einstein once made a very profound statement. He said, "Everything
should be made as simple as possible, but not simpler." The point I
was making is trying to explain *WHY* we use different kinds of
shielding and why some shielding won't work at all. If you understand
WHY you can make educated guesses about what will work and what won't.
And your "Basics" above are not 100% correct. So let's get down to a
real analysis.
Let's go back to the problem. The problem is that noise from the
strobe power supply is getting into the mic audio circuit. (I made a
mistake assuming that it was the strobe's inverter, i.e. audio whine
that changes pitch, as opposed to the "pop pop pop" noise of the
strobe ignition coil or the discharge of the cap through the
discharge tube but I digress.) The question then becomes, "how can
the signal get from the strobe power supply to the mic audio circuit
and this is where I started from.
First, how can the noise get out of the strobe power supply? It is
probably not RF as the rise times of the signals do not fall into the
RF spectrum. (Actually the "pop pop" noise could be RF borne but that
is not what we are talking about.) So it is either conducted or
radiated magnetically.
Now, how can the noise get into the audio panel or radio? As I see
it, there are two paths:
1. it can get in through the power lead;
2. it can get in through the mic input.
Let us treat #1. How can it get into the power lead? There are two ways:
1. it can be conducted by the bus in the form of voltage variations;
2. it can be induced inductively by the changing current in the power
or ground leads of the strobe power supply.
If the problem is #1 we will be able to see it with a scope on the
bus. Also, our battery should filter that out. I am betting that is
not the problem if the builder has been following Bob's
recommendations for wiring his airplane. (This is, after all, the
Aeroelectric list and you are here because Bob has been doing a good
job teaching you how to do a good job of wiring.)
If it is #2 we can attack the problem by minimizing inductive
coupling. There are four ways to reduce the inductive coupling:
1. Increase separation between the power wires going to the audio
panel/radio and the strobe power supply.
2. Reduce radiated magnetic field by binding the strobes power and
ground leads together or, better still, twisting them together. This
works because the current the the hot and ground leads are equal and
opposite so their magnetic fields will be equal and opposite. This
causes them to cancel out. This is one of the big reasons for running
a separate ground to a device rather than using the airframe as the
ground.
3. Reduce susceptance to magnetic fields in the audio panel by
running its power and ground leads together. (Again, twisting them is
even better.) Any varying magnetic field would induce equal and
opposite currents in the conductors and again they would cancel out.
4. You can use a magnetic shielding material like mu-metal around the
offending conductors to "trap" the lines of magnetic flux and keep
them from reaching (and influencing) other conductors.
(See: http://www.magnetic-shield.com/ for information on these kinds
of products.)
But if you haven't run your power and ground leads together you can
still "break the loop" and minimize the effect of inductive coupling
by putting a brute-force audio filter at or near the audio panel. (It
must be near the audio panel to eliminate the problem of inductive
coupling between the filter and the audio panel.) How does this work?
Well, the inductor acts as a high resistance to the AC part of the
signal (noise) while acting as a low resistance to the DC (power). It
therefore resists the transmission of the audio noise. The capacitor
acts as a low resistance to the AC part of the signal (noise),
shunting it to ground while not impeding the flow of power to the radio.
Shielding the power leads with some kind of copper braid or foil is
not going to do anything. The impedances of the circuits are just too
low.
OK, we have done the things I have mentioned above because they are
just good practice. But the noise is still present. This means it is
most likely getting in through the mic input.
Mic inputs in civil aircraft are low impedance, on the order of 200
ohms. Again, the noise is getting in either by conduction or
inductive coupling. It isn't getting in by capacitive coupling so a
braid/foil shield isn't going to do much. (Braid and foil shielding
work well at RF frequencies but that is not what we are dealing with
here.)
What we want to do is break any possibility for noise to get in as
conducted in either the mic signal lead or the mic ground lead.
If you ground the mic jack to the airframe there is a chance that the
strobe power supply will have its noise impressed on the ground of
the mic circuit. The airframe is like a big wire with all these
different currents flowing through it. But the airframe is like other
conductors and has some amount of voltage drop across it. If the
current in the strobe power supply is varying (it is) that same
variation appears in its ground wire. If that ground is the airframe
we have a varying current flowing through the airframe. That means
there will be different ground voltages at different points on the
airframe. If we also use the airframe as part of our ground circuit
for the mic by grounding the mic jack to the airframe (remember that
your audio panel is already grounded to the airframe through its
power ground), that voltage variation caused by the strobe ground
current now appears as part of the signal for the mic. Poof! Noise!
We get rid of this by insulating the mic jack from the airframe thus
eliminating the airframe as a possible source of noise in the mic
circuit.
Once we do that there is only one other way for noise to get into the
mic circuit. You got it right -- magnetic induction. How do we deal
with that? The same way we did with the power leads. We run the
signal and ground wires together, preferably twisting them. You don't
need a shield.
Now some of the people out there are asking, "But we were told to use
shielded wire for the mic jack. What gives?" Well, the shielding is
not doing anything for our audio noise pick up but it does have a
good effect to reduce RF noise pickup. So while the shielded wire
won't help to reduce our strobe noise problem it may help eliminate
any problem stemming from RF from our comm radio transmitter getting
into our mic audio circuit and causing a problem there. So we shield
our mic audio wiring using shielded wire just in case. Belt and
suspenders.
> Let the manufacture of the wire worry about resistance of 1000 Ft
> and the capacitive coupling / inductive coupling at AF & RF. The
> ONLY thing that would be of interest to our noise plagued brevien
> is the Percentage of Braid. You did not say anything about that!
Of course not. This is not an RF problem where braid effectiveness is
an issue. This is an AF problem and we just don't have high enough
impedances for electrostatic shielding to be of any consequence.
> Yet again as long as you use Mil-Spec wire the percentage of braid
> is acceptable and again our brevien does not have to be concerned.
Well, they have to be concerned in that you are trying to solve a
different problem from the one presented and your efforts are not
likely to be effective.
> As for the Separation of wires .... I did address that with my very
> first statement to Lucky; read above.
>
> I would suggest that all the AF noise (strobe noise) we are
> discussing be approached as I described AND then if the noise still
> exists just add another ground t=at the other end of the shield.
> It is MUCH easier to ADD a ground than to remove a ground.
As soon as you ground your shield in two places you have created a
loop of wire consisting of the braid and the airframe. Poof! Instant
ground loop. If I have a varying magnetic field near one conductor,
maybe your shield wire because you have routed it near the power lead
for some device, but that magnetic field isn't near my airframe
return so it doesn't get an equal and opposite current induced in it,
I am going to have a noise current conducted in that loop. You will
be able to tap off that noise from the airframe just about
anywhere ... such as with a mic jack that someone forgot to insulate.
There are a lot of things we just do because we were told we should.
But I think it makes a lot more sense to understand *WHY* we do it so
that we can guess at what might work and what might not. There are
many paths for unwanted signal (noise) to get from one device to
another. Understanding them and treating them separately will be much
more likely to rid us of a problem than will blindly shotgunning a
problem using rules-of-thumb that may or may not apply.
Brian Lloyd 361 Catterline Way
brian-yak AT lloyd DOT com Folsom, CA 95630
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
I fly because it releases my mind from the tyranny of petty things . . .
Antoine de Saint-Exupry
Message 8
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Subject: | Re: Electric failure |
--> AeroElectric-List message posted by: Brian Lloyd <brian-yak@lloyd.com>
On Jul 19, 2006, at 8:53 AM, Hopperdhh@aol.com wrote:
>
> Not being smart. Just wondering. Does this exist? If not, why not?
> If so,
> who does it?
>
> Thanks,
>
>
> Guy Buchanan
> K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar.
>
>
> This sounds a lot like my Garmin GPS295 and my Navaid autopilot.
Well, not quite. I see Bob's idea of a device that will hold an
aircraft on its current ground track using input from GPS as soon as
it is turned on. You don't need to enter a flight plan and you don't
need to tell the autopilot what heading to fly. Flip the 'on' switch
and the airplane unerringly locks onto its current ground track.
Pretty simple. Pretty elegant.
Brian Lloyd 361 Catterline Way
brian-yak AT lloyd DOT com Folsom, CA 95630
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
I fly because it releases my mind from the tyranny of petty things . . .
Antoine de Saint-Exupry
Message 9
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Subject: | magnetic shielding |
--> AeroElectric-List message posted by: Brian Lloyd <brian-yak@lloyd.com>
I mentioned magnetic shielding in my discussion about strobe noise
but it was buried in there pretty deeply and someone may have missed
it. I have used the magnetic shielding kit from Magnetic Shield Corp.
(http://www.magnetic-shield.com/) to solve DC and audio shielding
problems in aircraft before. They make a really cool magnetic braid/
sleeve you can slip over a conductor to attenuate any magnetic field
from that conductor that might cause a problem. I have used it to
solve problems with DC and low AC current causing a problem with a
panel-mounted CRT moving-map display. It "saved" my panel design.
They have a full-on kit of various sample materials with a meter that
will measure magnetic fields for about $200 but you can get the
materials alone for about $100. I bought the latter and found it very
useful.
Brian Lloyd 361 Catterline Way
brian-yak AT lloyd DOT com Folsom, CA 95630
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
I fly because it releases my mind from the tyranny of petty things . . .
Antoine de Saint-Exupry
Message 10
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Subject: | Re: Drop-out relay |
Thanks all for your suggestions.
At the moment, I have no means of determining "dryness".
I'm open to the simplest solution that's cost effective. The XFR fuel
controller switch would fit the job, if a little pricey. I like the idea
of a fuel pressure switch controlling a pump relay, but when there's no
pressure (switch open) how does the pump start? How much pressure is
req'd to close the switch? There's not much pressure developed in the
transfer line.
I'm using one of the Facet cube-shaped pumps.
John
Message 11
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Subject: | Re: Electric failure |
--> AeroElectric-List message posted by: Werner Schneider <glastar@gmx.net>
Hello Brian,
I switch my digitrack on and then it does track along the current track
which is supplied from the GPS, i have a left and a right button to
alter the course by a degree on each click, or keep it 3 sec pressed and
it will fly some sort of a standard rate turn (4min on my Glastar)
however I can also decide to use a flightplan from the GPS or without
GPS it does use the current flown magnetic course.
So quite close I would say ;)
Werner (Glastar with digitrack and altrak)
Brian Lloyd wrote:
> --> AeroElectric-List message posted by: Brian Lloyd
> <brian-yak@lloyd.com>
>
> On Jul 19, 2006, at 8:53 AM, Hopperdhh@aol.com wrote:
>
>>
>> Not being smart. Just wondering. Does this exist? If not, why not?
>> If so,
>> who does it?
>>
>> Thanks,
>>
>>
>> Guy Buchanan
>> K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar.
>>
>>
>>
>> This sounds a lot like my Garmin GPS295 and my Navaid autopilot.
>
>
> Well, not quite. I see Bob's idea of a device that will hold an
> aircraft on its current ground track using input from GPS as soon as
> it is turned on. You don't need to enter a flight plan and you don't
> need to tell the autopilot what heading to fly. Flip the 'on' switch
> and the airplane unerringly locks onto its current ground track.
> Pretty simple. Pretty elegant.
>
> Brian Lloyd 361 Catterline Way
> brian-yak AT lloyd DOT com Folsom, CA 95630
> +1.916.367.2131 (voice) +1.270.912.0788 (fax)
>
> I fly because it releases my mind from the tyranny of petty things . . .
> Antoine de Saint-Exupry
>
>
> http://www.matronics.com/Navigator?AeroElectric-List
> http://wiki.matronics.com
>
>
Message 12
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Subject: | Re: Drop-out relay |
--> AeroElectric-List message posted by: Brian Lloyd <brian-yak@lloyd.com>
On Jul 19, 2006, at 10:34 AM, John Burnaby wrote:
> Thanks all for your suggestions.
> At the moment, I have no means of determining "dryness".
> I'm open to the simplest solution that's cost effective. The XFR
> fuel controller switch would fit the job, if a little pricey. I
> like the idea of a fuel pressure switch controlling a pump relay,
> but when there's no pressure (switch open) how does the pump start?
> How much pressure is req'd to close the switch? There's not much
> pressure developed in the transfer line.
The pressure switch must be the normally open type, i.e. the pressure
switch contacts are open when there is no pressure. Put a momentary
contact switch in parallel with the pressure switch. When you press
the momentary contact switch and hold it for long enough that the
pump starts running, the pressure will activate the pressure switch
which will then keep the pump running until the tank runs dry. You
will need to hold the momentary switch on every time you want to
start the pump.
Make sure that the contacts in the pressure switch are rated to
handle the running current of the pump. The momentary contact switch
will handle the starting current for the pump.
Brian Lloyd 361 Catterline Way
brian-yak AT lloyd DOT com Folsom, CA 95630
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
I fly because it releases my mind from the tyranny of petty things . . .
Antoine de Saint-Exupry
Message 13
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Subject: | Re: Electric failure |
--> AeroElectric-List message posted by: "SteinAir, Inc." <stein@steinair.com>
I guess I'm kind of confused here.....why re-invent the wheel at all?!?
There is Navaid, Trio and TruTrak. They all literally do exactly what
everyone is debating here....turn them on and they work - Plain and simple.
What's wrong with the panel mounted displays in the low end AP's right now?
I mean, it takes a total of ONE button push to engage them and one to
disengage them....can it get much simpler?
It's easy to think that for a few bucks you can 'roll your own' which is
entirely true from a hardware perspective. But....anyone who think's
they'll create something to market, sell, support, install, warranty, etc..
is in for a really rude awakening. Bob knows the expense, time, effort and
engergy it takes and mark my words it's not a simple, cheap or quick
undertaking. I'll guarantee you that nobody can produce a servo cheaper
than TruTrak right now, seeing as they make around 50-100 of them per week,
every week. There is a reason they cost what they do...not because they are
getting particularly rich either.
Anyway, I'm just sort of scratching my head wondering why anyone would even
bother trying to recreate something that can readily be had for less that
$1500 today anyway (and from more than one source)? Heck, just the time
debating it, researching components, time to fabricate, etc.. and you've
already blown more than that in time alone.
No flames or insults intended, just trying to be realistic.
Cheers,
Stein
RV6's, Minneapolis
>-----Original Message-----
>From: owner-aeroelectric-list-server@matronics.com
>[mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Robert
>L. Nuckolls, III
>Sent: Wednesday, July 19, 2006 8:36 AM
>To: aeroelectric-list@matronics.com
>Subject: Re: AeroElectric-List: Re: Electric failure
>
>
>--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
><nuckollsr@cox.net>
>
>At 10:05 PM 7/18/2006 -0700, you wrote:
>
>>--> AeroElectric-List message posted by: Guy Buchanan <bnn@nethere.com>
>>
>>At 07:00 PM 7/18/2006, you wrote:
>>> But it's an inarguable, simple-idea that nobody keeps
>>> the wings level tirelessly and more accurately than
>>> a rate gyro, a handful of jelly bean parts and a servo motor.
>>> Add some GPS data and you've got a fantastic recipe for
>>> success. When the bill of materials and lines of software
>>> to do the task are 1/10th that of a panel mounted display
>>> (that depends on the eyeball-brain-hand interface)
>>> I can see no better cost benefit ratio or more elegant
>>> solution for lower complexity. And guess what? It absolutely
>>> guarantees and demonstrates lower cockpit workload.
>>
>>Not being smart. Just wondering. Does this exist? If not, why not? If so,
>>who does it?
>
> If anyone is close right now, it's Jim Younkin at
> TruTrak. I've had the core components of a design
> on the back burner for years and things really took
> a turn toward realization when Analog Devices finally
> slew the dragons for manufacturing an inexpensive, solid
> state rotation rate sensor. See:
>
>http://www.analog.com/en/prod/0%2C2877%2CADXRS401%2C00.html
>
> GPS engines are becomming jelly bean parts too. See:
>
>http://www.rfsolutions.co.uk/acatalog/Embedded_GPS_Module.html
>
> The hardware is a no-brainer. Development of a manufacturable
> product takes $time$ and ultimately an airplane . . . both
> of which are in my "pretty-hard" pile. But I'm still watching
> for opportunities to consider an entry into this market.
> Jim would be a most worthy competitor.
>
> Bob . . .
>
>
> ---------------------------------------------------------
> < What is so wonderful about scientific truth...is that >
> < the authority which determines whether there can be >
> < debate or not does not reside in some fraternity of >
> < scientists; nor is it divine. The authority rests >
> < with experiment. >
> < --Lawrence M. Krauss >
> ---------------------------------------------------------
>
>
Message 14
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|
John,
Have you considered using a GEMS sensor connected into the line coming
from the pump? The ELS-900 is smaller than the ELS-1100, and might be a
better choice for your application. Seems simple enough to implement
using a tee fitting. The GEMS sensor is solid state and uses a prism to
detect the presence/absence of liquid. That could control a relay which
would control the pump. You can pick up these sensors off ebay for
under $10/ea.
Mark S.
________________________________
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of John
Burnaby
Sent: Wednesday, July 19, 2006 9:35 AM
Thanks all for your suggestions.
At the moment, I have no means of determining "dryness".
I'm open to the simplest solution that's cost effective. The XFR fuel
controller switch would fit the job, if a little pricey. I like the idea
of a fuel pressure switch controlling a pump relay, but when there's no
pressure (switch open) how does the pump start? How much pressure is
req'd to close the switch? There's not much pressure developed in the
transfer line.
I'm using one of the Facet cube-shaped pumps.
John
Message 15
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Subject: | Re: Drop-out relay |
John,
1. Perhaps you try a pressure switch as used to activate the brake
lights, -low oil pressure, etc.
2. To create some pressure in the transfer line you will need a
restricting orifice downstream from the transfer pump, so some
experimentation will be needed.
3. The transfer starts by the Pilot pushing a button for a few seconds
or until the pressure is high enough to activate the switch which will
then hold the relay open all by itself, . . . and when the transfer tank
is getting low and the pump starts sucking air, the pressure will drop
below what is needed by the switch to hold the relay open, which will
then drop out shutting of the pump.
Relatively simple and cheap too (some thinking and tinkering required)
do not archive
----- Original Message -----
From: John Burnaby
To: aeroelectric-list@matronics.com
Sent: Wednesday, July 19, 2006 8:34 AM
Subject: Re: AeroElectric-List: Drop-out relay
Thanks all for your suggestions.
At the moment, I have no means of determining "dryness".
I'm open to the simplest solution that's cost effective. The XFR fuel
controller switch would fit the job, if a little pricey. I like the idea
of a fuel pressure switch controlling a pump relay, but when there's no
pressure (switch open) how does the pump start? How much pressure is
req'd to close the switch? There's not much pressure developed in the
transfer line.
I'm using one of the Facet cube-shaped pumps.
John
-------------------------------------------------------------------------
-----
No virus found in this incoming message.
7/18/2006
Message 16
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Subject: | Re: Electric failure |
--> AeroElectric-List message posted by: Brian Lloyd <brian-yak@lloyd.com>
On Jul 19, 2006, at 11:24 AM, Werner Schneider wrote:
> --> AeroElectric-List message posted by: Werner Schneider
> <glastar@gmx.net>
>
> Hello Brian,
>
> I switch my digitrack on and then it does track along the current
> track which is supplied from the GPS, i have a left and a right
> button to alter the course by a degree on each click, or keep it 3
> sec pressed and it will fly some sort of a standard rate turn (4min
> on my Glastar) however I can also decide to use a flightplan from
> the GPS or without GPS it does use the current flown magnetic course.
>
> So quite close I would say ;)
Sounds like it. I should know better than to open my mouth when I
haven't researched something. ;-)
Brian Lloyd 361 Catterline Way
brian-yak AT lloyd DOT com Folsom, CA 95630
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
I fly because it releases my mind from the tyranny of petty things . . .
Antoine de Saint-Exupry
Message 17
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Subject: | re: electric failure |
--> AeroElectric-List message posted by: Erich_Weaver@URSCorp.com
This has been an informative discussion for me guys - thanks.
I have a GRT EFIS and the Tru-Trak digiflight II (two axis), but no
experience operating or flying with them yet. The EFIS has a built-in GPS
and I additionally have second Garmin 296 that can pop in and out of the
panel. The thought was to have a backup for navigation in the event of
EFIS failure, and also so that I can punch in a flight plan at home and
then be able to hop in the plane whenever and instantly dump the flight
plan into the EFIS to control the autopilot.
Im a VFR kind of guy, but would like to understand what to expect regarding
the autopilot capabilities in the event of EFIS failure. Its my
understanding that the TruTrak has an internal magnetometer that comes into
play if the GPS or other input fails. Does this mean it will hold the
heading that was in use at the time of failure, or just that I could input
a new heading (assuming I remembered what the desired heading was).
Further, I assume that after EFIS failure I would be on my own with respect
to holding altitude, correct?
regards
Erich Weaver
Message 18
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Subject: | Re: Drop-out relay |
In a message dated 7/19/06 10:08:58 AM Central Daylight Time,
jonlaury@impulse.net writes:
> I like the idea of a fuel pressure switch controlling a pump relay, but
> when there's no pressure (switch open) how does the pump start?
>>>>
You could wire your start button in parallel with the NC pressure switch
contacts- make the "Pump On" button a momentary button and hold it in until the
pressure builds enough to close the contacts, then release the button. The
pressure switch contacts will hold the pump on until the fuel is gone and the
pressure drops, turning the pump off. An indicator light connected to the input
side of the pump motor would be useful here to tell you the pressure switch is
closed and the pump is operating. It will turn off once the pressure drops
and the pump stops.
Mark
Message 19
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Subject: | Re: Drop-out relay |
In a message dated 7/19/06 10:42:06 AM Central Daylight Time,
brian-yak@lloyd.com writes:
> The pressure switch must be the normally open type
>>>
Duh- I knew this but my fingers obviously didn't- Brian is right, natcherly!
Mark - do not archive
Message 20
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Subject: | Re: Help needed: continued strobe noise & weak radio |
--> AeroElectric-List message posted by: "Carlos Trigo" <trigo@mail.telepac.pt>
Another excellent piece of education from Brian Lloyd !
It's crystal clear and simple to understand and learn.
I don't know how you can find the time for this, but please keep up the good
work. I just love to read your postings, even the longest, because that's
the way why electric and electronic stuff is no longer voodoo to me!!
Thanks
Carlos
----- Original Message -----
Sent: Wednesday, July 19, 2006 3:16 PM
radio
> --> AeroElectric-List message posted by: Brian Lloyd <brian-yak@lloyd.com>
>
> On Jul 19, 2006, at 6:49 AM, FLYaDIVE@aol.com wrote:
>
>> Barry, you keep making statements like this but I am not sure you
>> have really thought through what you are saying.
>>
>> When you run two wires in parallel there are two coupling modes:
>> capacitive and inductive. When impedances are very high (it is
>> difficult to get current to flow) then capacitive coupling dominates.
>> When impedances are very low, as in power circuits, coupling is
>> inductive, with the current in one wire inducing a current in the
>> other wire by magnetic (inductive) coupling.
>>
>> Brian:
>>
>> I make these statements because I know they work.
>
> Copper braid or foil shield does not work to reduce inductive coupling
> between wires in low-impedance circuits at audio frequencies.
>
>> As for Inductive / capacitive coupling. We are talking DC circuits with
>> Noise in the AUDIO frequency range.
>
> Right.
>
>> As the saying goes: K.I.S.S. M.E. All this stuff about capacitive and
>> inductive coupling is not an issue in a simple noise problem as we are
>> discussing here.
>
> Actually, it is.
>
>> AND what the heck is "NON-MAGNETIC BRAID-TYPE SHIELDING"? Do you really
>> expect people to go out looking for "mu-metal"?
>
> Yes, if that is the problem they are trying to solve.
>
>> ALL the braid used on any electrical circuit on our planes is
>> NONMAGNETIC ... It is made of COPPER WIRE. Copper is non magnetic the
>> last time I checked. Again K.I.S.S. M.E. is the word of the day.
>
> But Barry, it isn't going to work in this application. There are magnetic
> shielding braids that are available. They look a bit like stainless steel
> braid and they work WONDERS for eliminating DC and audio effects on
> conductors carrying significant currents.
>
>> Electronics is simple, it is really!
>
> Well, like most things, it is simple if you understand it and have worked
> with it. It is not simple if you are ignorant of the principles. (And
> ignorance is not a bad thing as it can be remedied by education. It is
> only a bad thing if one chooses to remain ignorant.)
>
>> All these boog-a-boo statements only confuses the non-electrical types
>> amongst us.
>
> Confusion is eliminated through education. I happen to believe that
> anyone smart enough to successfully build an airplane is smart enough to
> learn and understand some basic electrical principles.
>
>> The only thing they need to know is how to remove the noise. Again that
>> goes back to the basics of noise, and breaking it down into DC and AC
>> ... AC goes one step further (Audio Frequencies [AF] and Radio
>> Frequencies [RF]).
>> Basics:
>> AF Noise - Shield and Ground at the source [This is why the Mic & Phone
>> lines use insulating washers at the jacks and ground at the audio panel
>> or radios.]
>> RF Noise - Shield and Ground at both ends. [Here is where exceptions
>> come into play - Some times the grounding is done through a capacitor.
>> BUT we are dealing with AF Noise not RF so I'm not going to try to
>> confuse people out there.]
>
> Einstein once made a very profound statement. He said, "Everything should
> be made as simple as possible, but not simpler." The point I was making
> is trying to explain *WHY* we use different kinds of shielding and why
> some shielding won't work at all. If you understand WHY you can make
> educated guesses about what will work and what won't.
>
> And your "Basics" above are not 100% correct. So let's get down to a real
> analysis.
>
> Let's go back to the problem. The problem is that noise from the strobe
> power supply is getting into the mic audio circuit. (I made a mistake
> assuming that it was the strobe's inverter, i.e. audio whine that changes
> pitch, as opposed to the "pop pop pop" noise of the strobe ignition coil
> or the discharge of the cap through the discharge tube but I digress.)
> The question then becomes, "how can the signal get from the strobe power
> supply to the mic audio circuit and this is where I started from.
>
> First, how can the noise get out of the strobe power supply? It is
> probably not RF as the rise times of the signals do not fall into the RF
> spectrum. (Actually the "pop pop" noise could be RF borne but that is not
> what we are talking about.) So it is either conducted or radiated
> magnetically.
>
> Now, how can the noise get into the audio panel or radio? As I see it,
> there are two paths:
>
> 1. it can get in through the power lead;
>
> 2. it can get in through the mic input.
>
> Let us treat #1. How can it get into the power lead? There are two ways:
>
> 1. it can be conducted by the bus in the form of voltage variations;
>
> 2. it can be induced inductively by the changing current in the power or
> ground leads of the strobe power supply.
>
> If the problem is #1 we will be able to see it with a scope on the bus.
> Also, our battery should filter that out. I am betting that is not the
> problem if the builder has been following Bob's recommendations for
> wiring his airplane. (This is, after all, the Aeroelectric list and you
> are here because Bob has been doing a good job teaching you how to do a
> good job of wiring.)
>
> If it is #2 we can attack the problem by minimizing inductive coupling.
> There are four ways to reduce the inductive coupling:
>
> 1. Increase separation between the power wires going to the audio
> panel/radio and the strobe power supply.
>
> 2. Reduce radiated magnetic field by binding the strobes power and ground
> leads together or, better still, twisting them together. This works
> because the current the the hot and ground leads are equal and opposite
> so their magnetic fields will be equal and opposite. This causes them to
> cancel out. This is one of the big reasons for running a separate ground
> to a device rather than using the airframe as the ground.
>
> 3. Reduce susceptance to magnetic fields in the audio panel by running
> its power and ground leads together. (Again, twisting them is even
> better.) Any varying magnetic field would induce equal and opposite
> currents in the conductors and again they would cancel out.
>
> 4. You can use a magnetic shielding material like mu-metal around the
> offending conductors to "trap" the lines of magnetic flux and keep them
> from reaching (and influencing) other conductors.
>
> (See: http://www.magnetic-shield.com/ for information on these kinds of
> products.)
>
> But if you haven't run your power and ground leads together you can still
> "break the loop" and minimize the effect of inductive coupling by putting
> a brute-force audio filter at or near the audio panel. (It must be near
> the audio panel to eliminate the problem of inductive coupling between
> the filter and the audio panel.) How does this work? Well, the inductor
> acts as a high resistance to the AC part of the signal (noise) while
> acting as a low resistance to the DC (power). It therefore resists the
> transmission of the audio noise. The capacitor acts as a low resistance
> to the AC part of the signal (noise), shunting it to ground while not
> impeding the flow of power to the radio.
>
> Shielding the power leads with some kind of copper braid or foil is not
> going to do anything. The impedances of the circuits are just too low.
>
> OK, we have done the things I have mentioned above because they are just
> good practice. But the noise is still present. This means it is most
> likely getting in through the mic input.
>
> Mic inputs in civil aircraft are low impedance, on the order of 200 ohms.
> Again, the noise is getting in either by conduction or inductive
> coupling. It isn't getting in by capacitive coupling so a braid/foil
> shield isn't going to do much. (Braid and foil shielding work well at RF
> frequencies but that is not what we are dealing with here.)
>
> What we want to do is break any possibility for noise to get in as
> conducted in either the mic signal lead or the mic ground lead.
>
> If you ground the mic jack to the airframe there is a chance that the
> strobe power supply will have its noise impressed on the ground of the
> mic circuit. The airframe is like a big wire with all these different
> currents flowing through it. But the airframe is like other conductors
> and has some amount of voltage drop across it. If the current in the
> strobe power supply is varying (it is) that same variation appears in its
> ground wire. If that ground is the airframe we have a varying current
> flowing through the airframe. That means there will be different ground
> voltages at different points on the airframe. If we also use the airframe
> as part of our ground circuit for the mic by grounding the mic jack to
> the airframe (remember that your audio panel is already grounded to the
> airframe through its power ground), that voltage variation caused by the
> strobe ground current now appears as part of the signal for the mic.
> Poof! Noise! We get rid of this by insulating the mic jack from the
> airframe thus eliminating the airframe as a possible source of noise in
> the mic circuit.
>
> Once we do that there is only one other way for noise to get into the mic
> circuit. You got it right -- magnetic induction. How do we deal with
> that? The same way we did with the power leads. We run the signal and
> ground wires together, preferably twisting them. You don't need a shield.
>
> Now some of the people out there are asking, "But we were told to use
> shielded wire for the mic jack. What gives?" Well, the shielding is not
> doing anything for our audio noise pick up but it does have a good effect
> to reduce RF noise pickup. So while the shielded wire won't help to
> reduce our strobe noise problem it may help eliminate any problem
> stemming from RF from our comm radio transmitter getting into our mic
> audio circuit and causing a problem there. So we shield our mic audio
> wiring using shielded wire just in case. Belt and suspenders.
>
>> Let the manufacture of the wire worry about resistance of 1000 Ft and
>> the capacitive coupling / inductive coupling at AF & RF. The ONLY thing
>> that would be of interest to our noise plagued brevien is the Percentage
>> of Braid. You did not say anything about that!
>
> Of course not. This is not an RF problem where braid effectiveness is an
> issue. This is an AF problem and we just don't have high enough
> impedances for electrostatic shielding to be of any consequence.
>
>> Yet again as long as you use Mil-Spec wire the percentage of braid is
>> acceptable and again our brevien does not have to be concerned.
>
> Well, they have to be concerned in that you are trying to solve a
> different problem from the one presented and your efforts are not likely
> to be effective.
>
>> As for the Separation of wires .... I did address that with my very
>> first statement to Lucky; read above.
>>
>> I would suggest that all the AF noise (strobe noise) we are discussing
>> be approached as I described AND then if the noise still exists just add
>> another ground t=at the other end of the shield. It is MUCH easier to
>> ADD a ground than to remove a ground.
>
> As soon as you ground your shield in two places you have created a loop
> of wire consisting of the braid and the airframe. Poof! Instant ground
> loop. If I have a varying magnetic field near one conductor, maybe your
> shield wire because you have routed it near the power lead for some
> device, but that magnetic field isn't near my airframe return so it
> doesn't get an equal and opposite current induced in it, I am going to
> have a noise current conducted in that loop. You will be able to tap off
> that noise from the airframe just about anywhere ... such as with a mic
> jack that someone forgot to insulate.
>
> There are a lot of things we just do because we were told we should. But
> I think it makes a lot more sense to understand *WHY* we do it so that we
> can guess at what might work and what might not. There are many paths for
> unwanted signal (noise) to get from one device to another. Understanding
> them and treating them separately will be much more likely to rid us of a
> problem than will blindly shotgunning a problem using rules-of-thumb that
> may or may not apply.
>
> Brian Lloyd 361 Catterline Way
> brian-yak AT lloyd DOT com Folsom, CA 95630
> +1.916.367.2131 (voice) +1.270.912.0788 (fax)
>
> I fly because it releases my mind from the tyranny of petty things . . .
> Antoine de Saint-Exupry
Message 21
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Subject: | Re: Help needed: continued strobe noise & weak radio |
--> AeroElectric-List message posted by: "Jerry Grimmonpre" <jerry@mc.net>
Brian ...
Your work on this subject has produced excellent information and
understanding. Your knowledge and genius are all telling. Is it now
possible you could boil all this down, into one simple, short, document?
Something we could post on our shop wall for quick reference. A single
piece of paper as to what's twisted, what's grounded and where, what's
grounded on one end and where and the other do's and don'ts? I've seen this
stuff scattered all over the electric list but I think it would help
everyone to have a consolidated list. Would you please consider doing this
for the list?
Many thanks ...
Jerry Grimmonpre'
RV4 Flying
RV8A Wire
--> AeroElectric-List message posted by: Brian Lloyd <brian-yak@lloyd.com>
On Jul 19, 2006, at 6:49 AM, FLYaDIVE@aol.com wrote:
Copper braid or foil shield does not work to reduce inductive
coupling between wires in low-impedance circuits at audio frequencies.
Well, like most things, it is simple if you understand it and have
worked with it. It is not simple if you are ignorant of the
principles. (And ignorance is not a bad thing as it can be remedied
by education. It is only a bad thing if one chooses to remain ignorant.)
Confusion is eliminated through education. I happen to believe that
anyone smart enough to successfully build an airplane is smart enough
to learn and understand some basic electrical principles.
Message 22
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Subject: | Re: Help needed: continued strobe noise & weak radio |
--> AeroElectric-List message posted by: Brian Lloyd <brian-yak@lloyd.com>
On Jul 19, 2006, at 12:48 PM, Carlos Trigo wrote:
> --> AeroElectric-List message posted by: "Carlos Trigo"
> <trigo@mail.telepac.pt>
>
> Another excellent piece of education from Brian Lloyd !
> It's crystal clear and simple to understand and learn.
> I don't know how you can find the time for this, but please keep up
> the good work. I just love to read your postings, even the longest,
> because that's the way why electric and electronic stuff is no
> longer voodoo to me!!
Thank you! I make these postings in the hope that it will help others
solve problems and understand how this stuff works. I am glad to hear
that I am successful.
They also give me the opportunity to exercise my grey matter on
problem solving. Use it or lose it! :-)
Brian Lloyd 361 Catterline Way
brian-yak AT lloyd DOT com Folsom, CA 95630
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
I fly because it releases my mind from the tyranny of petty things . . .
Antoine de Saint-Exupry
Message 23
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Subject: | Re: Help needed: continued strobe noise & weak radio |
--> AeroElectric-List message posted by: Brian Lloyd <brian-yak@lloyd.com>
On Jul 19, 2006, at 1:07 PM, Jerry Grimmonpre wrote:
> --> AeroElectric-List message posted by: "Jerry Grimmonpre"
> <jerry@mc.net>
>
> Brian ...
> Your work on this subject has produced excellent information and
> understanding. Your knowledge and genius are all telling. Is it
> now possible you could boil all this down, into one simple, short,
> document? Something we could post on our shop wall for quick
> reference. A single piece of paper as to what's twisted, what's
> grounded and where, what's grounded on one end and where and the
> other do's and don'ts? I've seen this stuff scattered all over the
> electric list but I think it would help everyone to have a
> consolidated list. Would you please consider doing this for the list?
> Many thanks ...
Huh. Interesting idea. Isn't there a chapter in the Aeroelectric
Connection that covers this? It has been a long time since I read
Bob's book but it struck me as a pretty good primer on this stuff.
Regardless, if it seems like a one-pager would be good to have around
I will try to generate one. Bob's book is clearly the seminal work on
the power wiring for an airplane. My experience is a bit more toward
audio and RF.
But right now I have to fix two bilge pumps. <sigh> The only place
nastier than the bilge on a boat is perhaps a septic tank.
Brian Lloyd 361 Catterline Way
brian-yak AT lloyd DOT com Folsom, CA 95630
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
I fly because it releases my mind from the tyranny of petty things . . .
Antoine de Saint-Exupry
Message 24
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Subject: | Re: Help needed: continued strobe noise & weak |
--> AeroElectric-List message posted by: Earl_Schroeder <Earl_Schroeder@juno.com>
I too would use a 'one page' summary of the 'ground' information. Bob's
book is good but like Jerry said, "this stuff scattered'. Thanks, Earl
Brian Lloyd wrote:
> --> AeroElectric-List message posted by: Brian Lloyd
> <brian-yak@lloyd.com>
>
>
> On Jul 19, 2006, at 1:07 PM, Jerry Grimmonpre wrote:
>
>> --> AeroElectric-List message posted by: "Jerry Grimmonpre"
>> <jerry@mc.net>
>>
>> Brian ...
>> Your work on this subject has produced excellent information and
>> understanding. Your knowledge and genius are all telling. Is it now
>> possible you could boil all this down, into one simple, short,
>> document? Something we could post on our shop wall for quick
>> reference. A single piece of paper as to what's twisted, what's
>> grounded and where, what's grounded on one end and where and the
>> other do's and don'ts? I've seen this stuff scattered all over the
>> electric list but I think it would help everyone to have a
>> consolidated list. Would you please consider doing this for the list?
>> Many thanks ...
>
> Huh. Interesting idea. Isn't there a chapter in the Aeroelectric
> Connection that covers this? It has been a long time since I read
> Bob's book but it struck me as a pretty good primer on this stuff.
>
> Regardless, if it seems like a one-pager would be good to have around
> I will try to generate one. Bob's book is clearly the seminal work on
> the power wiring for an airplane. My experience is a bit more toward
> audio and RF.
>
> But right now I have to fix two bilge pumps. <sigh> The only place
> nastier than the bilge on a boat is perhaps a septic tank.
>
> Brian Lloyd 361 Catterline Way
> brian-yak AT lloyd DOT com Folsom, CA 95630
> +1.916.367.2131 (voice) +1.270.912.0788 (fax)
>
> I fly because it releases my mind from the tyranny of petty things . . .
> Antoine de Saint-Exupry
>
>
> http://www.matronics.com/Navigator?AeroElectric-List
> http://wiki.matronics.com
>
>
Message 25
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Subject: | Electric failure |
--> AeroElectric-List message posted by: "glen matejcek" <aerobubba@earthlink.net>
Hi Jeff-
You raise a good question. Predictably, and no offense to any of the many
esteemed folks that have replied so far, the conversation has gone down the
path of system design. The questions you raise are different. As to what
would actually fail when the alt quits, on my plane nothing will. I can't
speak for the plane in question.
I think the issues raised by your article scenario are twofold. First, the
new, complex equipment tends to have a tremendous amount of functionality.
Typically, and unless beaten with a stick, pilots only use a small portion
of the power that is available to them. They then promptly forget how to
use the other 90% of the tools that are still available to them. I suspect
that is the point the storied instructor was trying to make. In other
words, stay proficient, and with your avionics as well.
The other issue is that given the loss of presented data, trying to macho
one's way out of the scenario is the wrong response. A more correct one
would be to inform ATC that they'd lost generation and were partial panel.
Holds are no longer acceptable, and intersection holds are ludicrous. Take
vectors, get out of IMC and onto the ground. It's just that simple. Do
not relinquish your fate to someone else's expectations.
We now return you to your normally scheduled systems engineering.
Feel free to flame away; I leave for OSH tomorrow and won't get scorched
for another 10 days or so!
glen matejcek
aerobubba@earthlink.net
Message 26
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Subject: | Re: Electric failure |
--> AeroElectric-List message posted by: "Paul McAllister" <paul.mcallister@qia.net>
Hi Bob,
I was wondering if you could clarify your thinking on this. Are you
proposing that you would install a pair of these simple devices for a fully
redundant system. Would this extend to having dual servos as well?
Just curious,
Paul
do not archive
-----Original Message-----
[mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Robert
L. Nuckolls, III
Sent: Wednesday, July 19, 2006 8:36 AM
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<nuckollsr@cox.net>
At 10:05 PM 7/18/2006 -0700, you wrote:
>--> AeroElectric-List message posted by: Guy Buchanan <bnn@nethere.com>
>
>At 07:00 PM 7/18/2006, you wrote:
>> But it's an inarguable, simple-idea that nobody keeps
>> the wings level tirelessly and more accurately than
>> a rate gyro, a handful of jelly bean parts and a servo motor.
>> Add some GPS data and you've got a fantastic recipe for
>> success. When the bill of materials and lines of software
>> to do the task are 1/10th that of a panel mounted display
>> (that depends on the eyeball-brain-hand interface)
>> I can see no better cost benefit ratio or more elegant
>> solution for lower complexity. And guess what? It absolutely
>> guarantees and demonstrates lower cockpit workload.
>
>Not being smart. Just wondering. Does this exist? If not, why not? If so,
>who does it?
If anyone is close right now, it's Jim Younkin at
TruTrak. I've had the core components of a design
on the back burner for years and things really took
a turn toward realization when Analog Devices finally
slew the dragons for manufacturing an inexpensive, solid
state rotation rate sensor. See:
http://www.analog.com/en/prod/0%2C2877%2CADXRS401%2C00.html
GPS engines are becomming jelly bean parts too. See:
http://www.rfsolutions.co.uk/acatalog/Embedded_GPS_Module.html
The hardware is a no-brainer. Development of a manufacturable
product takes $time$ and ultimately an airplane . . . both
of which are in my "pretty-hard" pile. But I'm still watching
for opportunities to consider an entry into this market.
Jim would be a most worthy competitor.
Bob . . .
---------------------------------------------------------
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
---------------------------------------------------------
Message 27
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Subject: | Electric failure |
--> AeroElectric-List message posted by: "Jeffery J. Morgan" <jmorgan@compnetconcepts.com>
Glen and others,
Actually I was asking more about the training and how closely it would
match a likely failure of a system. I was asking if the types of drills
that seem to be coming up for the Technically Advanced Aircraft (TAA)
seem to be built from the ideas of failures of years ago. I think it is
critical to recognize the past and learn from it, without getting to
arrogant to think that things couldn't fail totally. True that at any
time, anything can fail. I didn't say in my previous post, which I am
learning for the future, I was of the mindset that folks are building
systems where a single point of failure isn't really possible.
So try to my main question again, I think I would word like this. Given
that the article is focused on the least likely event (MFD failure) and
requesting an alternate form of navigation be used, does that seem like
it would be a good use of testing/training of pilots? Wouldn't it be
more prudent to drill more likely scenarios that are more likely then
1-5% likely? That is not to say that I disagree with the idea that you
need to keep your skills updates, regardless of what you are using as I
think you should. We do a disservice to other pilots and the public
when we fly into areas that we shouldn't because we lost GPS signal.
As for some of the points I have read over the past few days, I think
that there is merit in many of them. I think we could discuss all of
them at length. The interfaces on the systems are very different, each
with strong points and weak points. I think that I have often thought is
that the radio should have the closest frequencies in a list off the
tuning button as I fly along. I think it would be great to punch a
button and have a list of the closest ATIS or AWOS stations from my
position with a distance and bearing. Same for VORs. On the Garmin's
you can go to the nearest page and select, but it is a lot of dialing to
get there. With VOR's it isn't like I am going to dial much else in the
NAV radio. If I were 5000' or less, a list of airport CTAF or ATC
controlling facilities on the standby list would be helpful too.
Imagine hitting a button on the radio, and scroll though a list with the
frequency, definition, and direction right on the screen, with the
closest ones first... There is a feature that would lighten pilot loads
in difficult times. But all that said, maybe Brian would want it
differently than that. Never would claim that I am normal by any means.
I am building an airplane after all. :)
I think that part of the fundamental problem is that the folks writing
the rules, doing the check rides, and to a fair extent, doing the
training or still trying to catch up as well. I had that experience in
my flight training where the CFI didn't like to use certain pieces of
equipment, nor talk to ATC, so as a result when I got done, that stuff
was something I had to work on my own to acquire. TAA is flashy, but it
is a lot of work to learn. Maybe the need to demonstrate a VOR when
MFD failure happens is a reflection of that school of thought.
Personally, I would find things like engine failure, fire, gear
problems, control problems, IMC incursions, strong crosswinds, and even
busy airspace to be much more likely issues that people would run into
prior to failure of most of the systems on the plane, yet very few of
these are even discussed about training suddenly.
I would stress again that I strongly believe in training and preparing
for the worst, but think that the worst should be prioritized by most
likely to least likely and trained and tested in a similar order.
Message 28
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Subject: | SD-8 ALTERNATOR MOD FOR SELF EXCITATION |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
Thanks to the diligence of Jim McCulley we've tried a
modification to SD-8 alternator installations that
appears to be a good solution for getting the SD-8
to self excite. See revision L to Figure Z-25
at:
http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdf/Z25L.pdf
The Autocad version is at:
http://www.aeroelectric.com/PPS/ACAD_Architecture_Dwgs/Z24-25L.dwg
It's also been added to Appendix Z which steps the chapter up
to Revison J at:
http://aeroelectric.com/articles/Rev11/AppZ_R11J.pdf
See Note 25 and Figure Z-25
When I get time, I'll update all the other z-figures that use
an SD-8 to include the self-excitation feature.
Thanks again Jim!
Bob . . .
-----------------------------------------
( Experience and common sense cannot be )
( replaced with policy and procedures. )
( R. L. Nuckolls III )
-----------------------------------------
Bob . . .
---------------------------------------------------------
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
---------------------------------------------------------
Message 29
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Subject: | Re: Electric failure |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 06:01 PM 7/19/2006 -0500, you wrote:
>--> AeroElectric-List message posted by: "Paul McAllister"
><paul.mcallister@qia.net>
>
>Hi Bob,
>
>I was wondering if you could clarify your thinking on this. Are you
>proposing that you would install a pair of these simple devices for a fully
>redundant system. Would this extend to having dual servos as well?
>
>Just curious,
>
>Paul
Absolutely. A few months ago I related the demise of a good friend of
mine and his golfing buddies in a fatal event over New Mexico. See:
http://www.aeroelectric.com/articles/N79NL.pdf
This airplane had everything . . . including the kitchen sink. The
pilot was highly regarded, took all the Flight Safety refreshers,
keep the airplane up well. He was an engineer and manager of a business
that delivered LOTS of hardware to GA. He was about as far removed
from the Sunday afternoon fair weather, occasional instrument pilot
as you could find.
Nonetheless, he found himself faced with multiple failures of
expensive, certified but sadly INTERDEPENDENT systems that wrote
the script for an upset. After recovery, his abilities as a brass-or-glass
instrument pilot were severely degraded. In spite of having what
everyone considers "more than adequate" backup, he lost the airplane
a second time.
Sitting amongst attendees at his funeral, I recall thinking that
for lack of a redundant, totally independent killobuck wing leveler,
this didn't need to happen. If such a device had been available for
his airplane, I'm sure he would have installed one. At that time,
NavAid was the only game in town. Nowadays, theres a old-kid on the
block with a new game to play. It's called, "How about we never
need to touch the stick when in the clouds?"
The bill of materials for an airworthy device is peanuts. Having
TWO such systems totally independent of each other offers a HUGE
order of SYSTEM reliability over anything flying today, certified
or otherwise. The old-kid's product is a tad more expensive than
I think it needs to be . . . but who am I to bash the business
model of a very successful designer and honorable supplier to
the OBAM community? So, rather than bash, it seems more fitting
that I COMPETE . . .
But in the mean time, my participation doesn't prevent the
OBAM community from taking advantage of the opportunities
in place to help avoid becoming another NTSB statistic.
The neat thing is that hardware considered "unsuitable" for
use in N79NL is entirely suited to the task in OBAM aviation
and available off the shelf right now.
It just seems the logical way to go. I truly believe my friend Terry
would agree.
Bob . . .
Message 30
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Subject: | Re: SD-8 ALTERNATOR MOD FOR SELF EXCITATION |
--> AeroElectric-List message posted by: "Bob McCallum" <robert.mccallum2@sympatico.ca>
Thanks Bob (and Jim) - - - BUT - - - according to this modified version of
Z-25 the battery still needs to be in "good functioning condition" in order
to energize the S704-1 relay thus connecting the now self excited SD-8 to
the rest of the electrical system to utilize its output. If the battery is
of sufficient capacity to do this why couldn't we have used this same
capacity to excite the SD-8. What did we gain by its self excitation?? What
am I missing?? I would think an additional modification to Z-25 would be
required to actually make use of this self excitation. No ??
Bob McC
----- Original Message -----
Sent: Wednesday, July 19, 2006 11:55 PM
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<nuckollsr@cox.net>
>
>
> Thanks to the diligence of Jim McCulley we've tried a
> modification to SD-8 alternator installations that
> appears to be a good solution for getting the SD-8
> to self excite. See revision L to Figure Z-25
> at:
>
> http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdf/Z25L.pdf
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