Today's Message Index:
----------------------
1. 03:47 AM - Re: Cell phone ()
2. 06:15 AM - Re: Re: Cell phone (Kevin Horton)
3. 06:15 AM - thermocouple wires (Gary Casey)
4. 06:19 AM - Re: Re: Cell phone (Mickey Coggins)
5. 06:26 AM - Re: Re: Cell phone (Robert L. Nuckolls, III)
6. 06:33 AM - Re: thermocouple wires (Robert L. Nuckolls, III)
7. 06:40 AM - Re: Re: Cell phone (Robert L. Nuckolls, III)
8. 07:28 AM - Re: AeroElectric-List Digest: 20 Msgs - 03/30/06 (Ernest Christley)
9. 07:37 AM - Re: Re: Cell phone (Doug Windhorn)
10. 07:40 AM - Endurance Bus Diode & Voltage leak (sjhdcl@kingston.net)
11. 07:51 AM - Re: Re: Cell phone (Goguen, Jon)
12. 08:18 AM - Re: Endurance Bus Diode & Voltage leak (Matt Prather)
13. 08:25 AM - Re: thermocouple wires (Bill Dube)
14. 08:41 AM - Re: Endurance Bus Diode & Voltage leak (Robert L. Nuckolls, III)
15. 09:32 AM - Re: Re: Cell phone (Dave Morris \)
16. 09:43 AM - Re: Re: Cell phone (Dj Merrill)
17. 09:54 AM - Re: Endurance Bus Diode & Voltage leak (John Brick)
18. 10:50 AM - Re: Re: Cell phone (Lloyd, Daniel R.)
19. 12:41 PM - test (Jim Baker)
20. 01:20 PM - Re: thermocouple wires (David)
21. 02:26 PM - Questions for Bob N. April 1, 2006 (Eric M. Jones)
22. 03:04 PM - Re: Questions for Bob N. April 1, 2006 (Matt Prather)
23. 03:11 PM - Questions for Bob N. April 1, 2006 (Richard Riley)
24. 03:20 PM - Re: Questions for Bob N. April 1, 2006 (John W. Cox)
25. 03:55 PM - Re: Questions for Bob N. April 1, 2006 (David)
26. 04:14 PM - Re: Questions for Bob N. April 1, 2006 (Dave Morris \)
27. 06:52 PM - Re: Questions for Bob N. April 1, 2006 (William Yamokoski)
28. 11:04 PM - Dead face Annunciators ()
29. 11:53 PM - Re: Dead face Annunciators (Mickey Coggins)
Message 1
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--> AeroElectric-List message posted by: <gmcjetpilot@yahoo.com>
Actually air carrier, schedule passenger airline, have FAR restrictions.
If its company policy (in the operation certificate or airline flt manual it's
law), it is
forbidden. The FAR's are less spacific and more general, giving the Captain
(PIC) authority to allow certain portable electronic devices. However if explicitly
stated in the Op Spec's his hands are tied. Flight attendants are doing their
job.
Airlines have there own set of custom rules they must abide by.
Most airlines allow cell use on the ground, after landing during taxi.
In flight below 10,000 forget any device.
Any Fan's of the Discovery Channel show Myth Busters? One
of the most recent discussed this very thing. It was interesting. It was
Episode 49,"Cell Phones on a Plane", first aired on March 15, 2006.
http://en.wikipedia.org/wiki/MythBusters_episodes:_Season_3#Episode_49_.E2.80.94_.22Cell_Phones_on_a_Plane.22
They did a test with a high powered Cell test transmitter and got an old
Cessna ARC VOR to jump. They tried it in Hawker Business Jet with
EFIS flight deck. No effect. They wanted to fly but where not allowed by
the FAA? FCC? The bottom line was it was BUSTED! Older aircraft can
be affected, but modern shielded systems are virtually impervious.
The FAA's stand at least with commercial traffic is to err on the side of
conservatism. At some lower altitude they will not work anyway.
Check local basic cable listings, it is well worth a watch.
How the cell phone companies feel about it? I don't know. I always heard
it would "block" too many towers but read here this is untrue?
Any device can put out RF. I don't want an argument of shielded
electronics, we are talking conservatism. Frankly if I am IMC flying an
apprach to Mins, I don't want any electronic decives on.
What about GA aviation? Well it is one of those things, no harm not foul?
Cheers George
---------------------------------
Message 2
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--> AeroElectric-List message posted by: Kevin Horton <khorton01@rogers.com>
On 31 Mar 2006, at 06:39, <gmcjetpilot@yahoo.com>
<gmcjetpilot@yahoo.com> wrote:
> --> AeroElectric-List message posted by: <gmcjetpilot@yahoo.com>
>
> http://en.wikipedia.org/wiki/
> MythBusters_episodes:_Season_3#Episode_49_.E2.80.94_.
> 22Cell_Phones_on_a_Plane.22
>
>
> They did a test with a high powered Cell test transmitter and got
> an old
> Cessna ARC VOR to jump. They tried it in Hawker Business Jet with
> EFIS flight deck. No effect. They wanted to fly but where not
> allowed by
> the FAA? FCC? The bottom line was it was BUSTED! Older aircraft can
> be affected, but modern shielded systems are virtually impervious.
> The FAA's stand at least with commercial traffic is to err on the
> side of
> conservatism. At some lower altitude they will not work anyway.
There are so many variables that it is pretty much impossible to
define a guaranteed safe set of circumstances to use personal
electronic devices. One device might be OK, but the next one of the
same model was misassembled, or dropped, and that could affect the
shielding. Most seats in an aircraft might be OK, but a few seats
might be close to a coax connector that might allow some signal to
leak into the coax. Most aircraft might be OK, but one serial number
might have a bad piece of coax. One cell phone model might be OK,
until the manufacturer changes the production process.
A few tests showing no interference do not constitute proof that
there cannot be interference under any circumstances. There have
been enough reports of interference from various devices to know that
there can be problems in the right set of circumstances.
I talked to a Canadair Challenger pilot about 10 years ago who
related an incident. They were in cruise, when they noted strange
indications on the NAVs. He sent the copilot back to the cabin to
see if anything strange was going on. He found the CEO's son playing
with a GameBoy. He asked him to turn the GameBoy OFF - the NAVs
returned to normal. Turned the GameBoy back ON, the NAVs started
acting up again. GameBoy OFF for the rest of the flight.
> Any device can put out RF. I don't want an argument of shielded
> electronics, we are talking conservatism. Frankly if I am IMC
> flying an
> apprach to Mins, I don't want any electronic decives on.
I agree 100% for commercial ops. For private ops, it is up to the
PIC to use his own best judgement.
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://www.kilohotel.com/rv8
Message 3
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| Subject: | thermocouple wires |
--> AeroElectric-List message posted by: Gary Casey <glcasey@adelphia.net>
Cold junction compensation: I have a system from Grand Rapids
Technology that recommends using ThermoCouple(TC) wire all the way
from the box to the TC connectors on the engine. The CHT uses type J
and the EGT type K. The people that did my panel used copper to a
bulkhead connector (expensive Mil-spec with gold-plated terminals)
and then I, without too much thinking, kept going with copper wire to
each TC connector. Now I'm worried about the errors will occur
because of all the wire material mismatch. The only good thing going
is that the TC wires are equal length so the + and - connectors are
right next to each other. Big errors? Small errors? I'm almost
tempted to pull out the whole thing, bulkhead connector and all, and
run TC wire in one length from the box to each TC. I looked at the
JPI system in my certified aircraft and that's the way it was done.
And then while I'm at it I could buy real TC connectors that will
keep all the materials correct. Should I?
Gary Casey
Message 4
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--> AeroElectric-List message posted by: Mickey Coggins <mick-matronics@rv8.ch>
> How the cell phone companies feel about it? I don't know. I always heard
> it would "block" too many towers but read here this is untrue?
I'm happy we have federal laws to protect the telcos when
they don't properly engineer their products.
Any of you that live in the mountains know that you can
get a signal from dozens of cell towers at any instant
when you are high on a mountain. The tower my cell
phone (GSM) normally attaches to is about 12 miles
away, across the lake. Sometimes I get one about
the same distance, but about another 10 miles south.
My phone is seeing *lots* of towers, as are all of
the other thousands of people that live in these
hills.
Also, back in the early 90s when GSM first came out,
I never turned off my phone. There was no PA
announcement asking you to do it, since almost no
one had a cell phone. I flew a lot (commercial)
and enjoyed tracking my progress by watching the
towers that I attached to with the "debug" mode
active my phone. I tried to make a call, and
even though I had a nice signal, I could never
make a call. Not once. My bud who is a GSM guru
said that at the speed we were flying, I was not
staying on a tower long enough. I think until
there are "towers" installed in the aircraft, we won't
have to worry about sitting next to someone yaking
their heads off.
--
Mickey Coggins
http://www.rv8.ch/
#82007 finishing
do not archive
Message 5
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--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 03:39 AM 3/31/2006 -0800, you wrote:
>--> AeroElectric-List message posted by: <gmcjetpilot@yahoo.com>
>
>Actually air carrier, schedule passenger airline, have FAR restrictions.
>
> If its company policy (in the operation certificate or airline flt
> manual it's law), it is
>forbidden. The FAR's are less spacific and more general, giving the Captain
>(PIC) authority to allow certain portable electronic devices. However if
>explicitly
> stated in the Op Spec's his hands are tied. Flight attendants are doing
> their job.
>
> Airlines have there own set of custom rules they must abide by.
>
>Most airlines allow cell use on the ground, after landing during taxi.
>In flight below 10,000 forget any device.
>
>
>Any Fan's of the Discovery Channel show Myth Busters? One
>of the most recent discussed this very thing. It was interesting. It was
>Episode 49,"Cell Phones on a Plane", first aired on March 15, 2006.
>
>http://en.wikipedia.org/wiki/MythBusters_episodes:_Season_3#Episode_49_.E2.80.94_.22Cell_Phones_on_a_Plane.22
>
>
>They did a test with a high powered Cell test transmitter and got an old
>Cessna ARC VOR to jump. They tried it in Hawker Business Jet with
>EFIS flight deck. No effect. They wanted to fly but where not allowed by
>the FAA? FCC? The bottom line was it was BUSTED!
<snip>
I saw this episode. If it were not offered with such good
intentions, it would have been laughable. Their techniques
for deducing sensitivity of various systems to radiation from
cell phone emissions demonstrated a complete lack of understanding
of how both systems work and how one conducts repeatable experiments
to quantify and qualify results.
Take it from someone who has written dozens of test plans and
spent a goodly part of a career in a screen-room, the "results"
from their tests had no scientific validity. Now, that's not
to say that their conclusion was incorrect . . . I've done a LOT
of testing of equipment that was radiated strongly by sources
that cover the cell phone frequencies and found no effect on
the equipment under test. Indeed, that's a design goal of the
supplier and a requirement for certification. Suffice it to say
that squirting a bit of RF around the cockpit while watching to
see if anything twitches is not a noteworthy test . . . I WISH
it were so simple. Could have save my bosses $millions$.
Bob . . .
Message 6
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| Subject: | Re: thermocouple wires |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 06:12 AM 3/31/2006 -0800, you wrote:
>--> AeroElectric-List message posted by: Gary Casey <glcasey@adelphia.net>
>
>Cold junction compensation: I have a system from Grand Rapids
>Technology that recommends using ThermoCouple(TC) wire all the way
>from the box to the TC connectors on the engine. The CHT uses type J
>and the EGT type K. The people that did my panel used copper to a
>bulkhead connector (expensive Mil-spec with gold-plated terminals)
>and then I, without too much thinking, kept going with copper wire to
>each TC connector. Now I'm worried about the errors will occur
>because of all the wire material mismatch. The only good thing going
>is that the TC wires are equal length so the + and - connectors are
>right next to each other. Big errors? Small errors? I'm almost
>tempted to pull out the whole thing, bulkhead connector and all, and
>run TC wire in one length from the box to each TC. I looked at the
>JPI system in my certified aircraft and that's the way it was done.
>And then while I'm at it I could buy real TC connectors that will
>keep all the materials correct. Should I?
One is never wrong to follow the manufacturer's instructions.
Your concerns for degraded calibration of the instruments
due to mis-wiring are well founded. See chapter 14 in the 'Connection.
Thermocouples are neat things. They work well but only if
one follows the design rules. As soon as you stick a foreign
material (copper) in the loop, one must DESIGN for a specific
set of circumstances that should honored if you want to
maintain system integrity. If the manufacturer calls for
100% t/c wire from measurement of interest to the instrument,
then those are the rules.
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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--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 09:10 AM 3/31/2006 -0500, you wrote:
>--> AeroElectric-List message posted by: Kevin Horton <khorton01@rogers.com>
>
<snip>
>I talked to a Canadair Challenger pilot about 10 years ago who
>related an incident. They were in cruise, when they noted strange
>indications on the NAVs. He sent the copilot back to the cabin to
>see if anything strange was going on. He found the CEO's son playing
>with a GameBoy. He asked him to turn the GameBoy OFF - the NAVs
>returned to normal. Turned the GameBoy back ON, the NAVs started
>acting up again. GameBoy OFF for the rest of the flight.
>
> > Any device can put out RF. I don't want an argument of shielded
> > electronics, we are talking conservatism. Frankly if I am IMC
> > flying an
> > apprach to Mins, I don't want any electronic decives on.
>
>I agree 100% for commercial ops. For private ops, it is up to the
>PIC to use his own best judgement.
>
>
>Kevin Horton RV-8 (finishing kit)
This was almost certainly an in-band interference event . . .
meaning that the interfering device had emissions on a specific
frequency of interest. What the Mythbusters did not understand
was that risks were probably NOT due to emissions on the cell-phone's
frequency of operation but for unexplored and uncontrolled emissions
on OTHER frequencies shared with the aircraft's systems.
The idea that emissions on cell phone frequencies would affect anything
in the cockpit is a very weak concern . . . those things are fully
explored during certification of that equipment. The concern is that
electronics in the foreign system has emissions in the vhf or uhf
frequencies where on-board equipment is trying to resolve signals
of interest in the microvolt levels while being bombarded with
much stronger, local interference.
Bob . . .
Message 8
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| Subject: | Re: AeroElectric-List Digest: 20 Msgs - 03/30/06 |
--> AeroElectric-List message posted by: Ernest Christley <echristley@nc.rr.com>
AeroElectric-List Digest Server wrote:
--> AeroElectric-List message posted by: "John Schroeder" <jschroeder@perigee.net>
Do Not Archive
I'm very indebted and relieved if this is the case, and hope it will
remain the policy of the airlines to ban the use of cell phones while the
aircraft is away from the gate. I can imagine how bad it would be to be
held captive for hours while the usual cell phone bore orders an underling
or their secretary around in a loud voice, or relates intimate details
from the previous night's liaison, or in a similarly loud voice, relates
in detail the long string of other problems in their life. In a restaurant
or the terminal one can put some distance between the annoyance and
themselves. In the usual crammed cattle car we fly in these days? Abu
Ghraib anyone?
Cheers,
John Schroeder
You do know how to end that particular irritation real quick don't you?
Join in on their conversation! It was they that invite you in when they
hang their dirty laundry in public. Say something loud and obnoxious,
but supportive, something along the lines of, "Yeah, you tell 'er,
buddy! Don't let that woman push you around like that.", or "Heh, I had
a secretary act like that once. I fired her, and that's what you should
do." Or even better, "You did have your shirts dry cleaned, didn't
you? Don't want your jilted wife catching that lipstick on your collar."
They'll shut-up once they realize they're in public and not a telephone
booth.
--
,|"|"|, Ernest Christley |
----===<{{(oQo)}}>===---- Dyke Delta Builder |
o| d |o www.ernest.isa-geek.org |
Message 9
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--> AeroElectric-List message posted by: "Doug Windhorn" <N1DeltaWhiskey@comcast.net>
----- Original Message -----
From: "Mickey Coggins" <mick-matronics@rv8.ch>
Sent: Friday, 31 March, 2006 6:18
Subject: Re: AeroElectric-List: Re: Cell phone
>> snip<< I tried to make a call, and
> even though I had a nice signal, I could never
> make a call. Not once. My bud who is a GSM guru
> said that at the speed we were flying, I was not
> staying on a tower long enough. I think until
> there are "towers" installed in the aircraft, we won't
> have to worry about sitting next to someone yaking
> their heads off.
>> snip <<
Hallelujah! Thank you for small blessings. Now if they could only make the
towers cut off communications when the phone is moving above 20 mph!
Alluding, of course, to all those who feel their attention to detail is not
diverted by running their mouth.
Doug Windhorn
Message 10
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| Subject: | Endurance Bus Diode & Voltage leak |
--> AeroElectric-List message posted by: sjhdcl@kingston.net
Bob,
Is it normal for a diode to leak voltage back onto the MAIN bus?
With the EBus X Feed Switch on (no MAIN bus) it get 12.8V at the Endurance
bus and about 6.85 V at the MAIN bus terminal. With the MASTER Off.
I understand the forward voltage drop when the MAIN bus is powered and I
measured it to be 0.6V. But I can't find any reference to this backwards
'leak' of voltage by the diode.
The diode is the standard 1" by 1" block (D-25) from B&C.
Another question: Some diagrams show only attaching 2 of the tabs on the
diode. One to Endurance and one to MAIN.
Other diagram shows joining the two terminal on the diode and then going
to the Endurance Bus. Is this for redundancy since these 2 terminals are
electrically the same?
Steve
RV7A
Message 11
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--> AeroElectric-List message posted by: "Goguen, Jon" <Jon.Goguen@umassmed.edu>
I have similar experence to Mickey's. On mountain ridges, high signal strength
indications are common, although if the distance from the tower is large communication
is frequently impossible. I did try one experiment from 9000 ft over
Rochester, NY in a Skylane. All the bars and the phone where lit up, but all
a got was a poor connection that lasted for a few seconds.
Jon
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com on behalf of Mickey Coggins
Sent: Fri 3/31/2006 9:18 AM
Subject: Re: AeroElectric-List: Re: Cell phone
--> AeroElectric-List message posted by: Mickey Coggins <mick-matronics@rv8.ch>
> How the cell phone companies feel about it? I don't know. I always heard
> it would "block" too many towers but read here this is untrue?
I'm happy we have federal laws to protect the telcos when
they don't properly engineer their products.
Any of you that live in the mountains know that you can
get a signal from dozens of cell towers at any instant
when you are high on a mountain. The tower my cell
phone (GSM) normally attaches to is about 12 miles
away, across the lake. Sometimes I get one about
the same distance, but about another 10 miles south.
My phone is seeing *lots* of towers, as are all of
the other thousands of people that live in these
hills.
Also, back in the early 90s when GSM first came out,
I never turned off my phone. There was no PA
announcement asking you to do it, since almost no
one had a cell phone. I flew a lot (commercial)
and enjoyed tracking my progress by watching the
towers that I attached to with the "debug" mode
active my phone. I tried to make a call, and
even though I had a nice signal, I could never
make a call. Not once. My bud who is a GSM guru
said that at the speed we were flying, I was not
staying on a tower long enough. I think until
there are "towers" installed in the aircraft, we won't
have to worry about sitting next to someone yaking
their heads off.
--
Mickey Coggins
http://www.rv8.ch/
#82007 finishing
do not archive
Message 12
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| Subject: | Re: Endurance Bus Diode & Voltage leak |
--> AeroElectric-List message posted by: "Matt Prather" <mprather@spro.net>
Reverse biased diodes _do_ leak (current). Maybe a few microamps.
The voltage behind a reverse biased diode will depend on what it's
connected to. Presumably, the bus that your diode is connected to has all
of the switches turned off - very light loading with which to discharge
the leakage current through the diode. I would guess that if you
connected a 1kohm resistor between the bus and ground and remeasured the
voltage, it would be very low (V = IR = 0.000005A * 1000ohm = 0.005V).
Matt-
> --> AeroElectric-List message posted by: sjhdcl@kingston.net
>
> Bob,
>
> Is it normal for a diode to leak voltage back onto the MAIN bus?
>
> With the EBus X Feed Switch on (no MAIN bus) it get 12.8V at the
> Endurance bus and about 6.85 V at the MAIN bus terminal. With the MASTER
> Off.
>
> I understand the forward voltage drop when the MAIN bus is powered and I
> measured it to be 0.6V. But I can't find any reference to this backwards
> 'leak' of voltage by the diode.
>
> The diode is the standard 1" by 1" block (D-25) from B&C.
>
> Another question: Some diagrams show only attaching 2 of the tabs on the
> diode. One to Endurance and one to MAIN.
>
> Other diagram shows joining the two terminal on the diode and then going
> to the Endurance Bus. Is this for redundancy since these 2 terminals
> are electrically the same?
>
> Steve
> RV7A
>
>
Message 13
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| Subject: | Re: thermocouple wires |
--> AeroElectric-List message posted by: Bill Dube <william.p.dube@noaa.gov>
In a thermocouple circuit, the voltage is generated along the wire as it
passes through regions of different temperature. If part of the circuit
is the wrong alloy (like the connectors, contacts, joints, wire,
corrosion,) and there is a temperature difference across these regions
of incorrect alloy, you will get the wrong temperature reading.
The error will depend on how big the temperature gradient is, and
the Seebeck coefficient of the improper alloy in that region. Copper
oxide, for example, has HUGE Seebeck coefficient, so the errors
generated at slightly corroded copper joints can be enormous.
Having said all that, keep in mind that if there is no temperature
gradient, no voltage is generated.
Also, if both legs of the circuit are the same alloy, and are
subjected to the same temperature gradient, no voltage will be
generated. This can be good, or bad. If you have copper wires running
from the gage to the engine block, then TC wire running from the block
to the exhaust probe, the gage will read the difference in temperature
between the block and the probe (approximately.) If the block was hot,
and the probe slightly colder, you would read a negative temperature on
the gage.
Complicating this is the reference (cold) junction compensation in
the gage. It assumes that you have the correct alloy wire everywhere. It
will add or subtract the temperature of the gage from the voltage it
reads from the TC circuit. If the transition from copper wire to TC wire
is not at the gage terminals, but on the engine block, the reading will
be off by the difference in temperature between the block and the gage.
The firewall bulkhead connector and the connector near the engine
are the ones to be concerned about. They are almost certain to have a
significant temperature difference imposed on them. If they are not the
correct alloy, they will introduce an error.
Connectors with the correct alloy are not terribly expensive.
Sometimes you can buy pins for existing connectors that are the proper
TC alloys. Teflon TC wire is also not very expensive. If you want the
reading on the gage to be correct, take the time to do the wiring correctly.
Bill Dube'
Gary Casey wrote:
>--> AeroElectric-List message posted by: Gary Casey <glcasey@adelphia.net>
>
>Cold junction compensation: I have a system from Grand Rapids
>Technology that recommends using ThermoCouple(TC) wire all the way
>from the box to the TC connectors on the engine. The CHT uses type J
>and the EGT type K. The people that did my panel used copper to a
>bulkhead connector (expensive Mil-spec with gold-plated terminals)
>and then I, without too much thinking, kept going with copper wire to
>each TC connector. Now I'm worried about the errors will occur
>because of all the wire material mismatch. The only good thing going
>is that the TC wires are equal length so the + and - connectors are
>right next to each other. Big errors? Small errors? I'm almost
>tempted to pull out the whole thing, bulkhead connector and all, and
>run TC wire in one length from the box to each TC. I looked at the
>JPI system in my certified aircraft and that's the way it was done.
>And then while I'm at it I could buy real TC connectors that will
>keep all the materials correct. Should I?
>
>Gary Casey
>
>
>
>
>
>
>
>
>
Message 14
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| Subject: | Re: Endurance Bus Diode & Voltage leak |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 10:40 AM 3/31/2006 -0500, you wrote:
>--> AeroElectric-List message posted by: sjhdcl@kingston.net
>
>Bob,
>
>Is it normal for a diode to leak voltage back onto the MAIN bus?
>
>With the EBus X Feed Switch on (no MAIN bus) it get 12.8V at the Endurance
>bus and about 6.85 V at the MAIN bus terminal. With the MASTER Off.
>
>I understand the forward voltage drop when the MAIN bus is powered and I
>measured it to be 0.6V. But I can't find any reference to this backwards
>'leak' of voltage by the diode.
>
>The diode is the standard 1" by 1" block (D-25) from B&C.
Diodes are not 'perfect' . . . they have forward voltage drop
and reverse leakage. Keep in mind that the input impedance of
a digital voltmeter is on the order of 10-20 MEGohms. To get
a reading of 6.85 volts due to leakage, you need only
6.85/10,000,000 or 685 NANOamps. If you turn on any single load
on the main bus, the reading will drop like a stone.
I went to the bench and wired a Fluke multimeter, 12v supply
and several diodes in series with a voltage measurement crafted
to show the effects of diode reverse leakage. From a selection
of parts in the bins, I got reverse leakage voltage readings from
.3 to 7.5 volts on regulator power silicon junction diodes.
When I measured a Shottky device, the leakage reading was 12V! I put
a 10,000 ohm load across the voltmeter and the reading dropped to
.25 volts. This shows that Shottky device leakage is several orders
of magnitude greater than for silicon junctions.
Bottom line is that your readings are understandable and not
significant in the grand scheme of things.
>Another question: Some diagrams show only attaching 2 of the tabs on the
>diode. One to Endurance and one to MAIN.
>
>Other diagram shows joining the two terminal on the diode and then going
>to the Endurance Bus. Is this for redundancy since these 2 terminals are
>electrically the same?
The four diodes contained in a bridge rectifier are identical.
If you noodle out their position in the device, you can use any
of 4 combinations of terminals to effect the desired operation.
But you can't go wrong with wiring per:
http://www.aeroelectric.com/Pictures/Wiring_Technique/diode_wiring.jpg
http://www.aeroelectric.com/Pictures/Misc/s401-25.jpg
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 15
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--> AeroElectric-List message posted by: "Dave Morris \"BigD\"" <BigD@DaveMorris.com>
After trying unsuccessfully to implement a Pentium II 120MHz computer
in the cockpit of my airplane (until I suddenly realized, duh, that
the clock speed was smack dab in the middle of the aircraft band and
would break the squelch full quieting on about 100 different commonly
used aircraft comm frequencies), and then switching to a 240MHz
version of the same computer and still wiping out the entire aircraft
band with RF interference, I honestly don't know how airliners stayed
in the air back in the days when laptops were running at such slow speeds.
But, as Bob said below, it's not just the "one" main frequency that's
producing interference. In a laptop computer there are several
different clocks (aka transmitters) all putting out junk. In a
cellphone, you might have oscillators for the receiving circuits,
oscillators for the transmitting circuits, oscillators for the LCD
display, oscillators for the dial pad, the PC sync cable, the
bluetooth, the WiFi, the 400MHz CPU, etc. etc. etc. Every oscillator
puts out a signal on its design frequency, and on harmonics (2x, 3x,
4x, etc.), so I imagine a spectrum analysis of a typical airliner
with everybody playing on laptops, gameboys, PDAs, DVD players, etc.
must be an incredibly awesome sight.
I agree that the mythbusters have strayed and nowadays most of their
shows are mostly entertainment, with little real scientific evidence
to back up their "busted / not busted" binary logic.
Dave Morris
At 08:24 AM 3/31/2006, you wrote:
>--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
><nuckollsr@cox.net>
>
>At 03:39 AM 3/31/2006 -0800, you wrote:
>
> >--> AeroElectric-List message posted by: <gmcjetpilot@yahoo.com>
> >
> >Actually air carrier, schedule passenger airline, have FAR restrictions.
> >
> > If its company policy (in the operation certificate or airline flt
> > manual it's law), it is
> >forbidden. The FAR's are less spacific and more general, giving the Captain
> >(PIC) authority to allow certain portable electronic devices. However if
> >explicitly
> > stated in the Op Spec's his hands are tied. Flight attendants are doing
> > their job.
> >
> > Airlines have there own set of custom rules they must abide by.
> >
> >Most airlines allow cell use on the ground, after landing during taxi.
> >In flight below 10,000 forget any device.
> >
> >
> >Any Fan's of the Discovery Channel show Myth Busters? One
> >of the most recent discussed this very thing. It was interesting. It was
> >Episode 49,"Cell Phones on a Plane", first aired on March 15, 2006.
> >
> >http://en.wikipedia.org/wiki/MythBusters_episodes:_Season_3#Episode
> _49_.E2.80.94_.22Cell_Phones_on_a_Plane.22
> >
> >
> >They did a test with a high powered Cell test transmitter and got an old
> >Cessna ARC VOR to jump. They tried it in Hawker Business Jet with
> >EFIS flight deck. No effect. They wanted to fly but where not allowed by
> >the FAA? FCC? The bottom line was it was BUSTED!
>
>
> <snip>
>
> I saw this episode. If it were not offered with such good
> intentions, it would have been laughable. Their techniques
> for deducing sensitivity of various systems to radiation from
> cell phone emissions demonstrated a complete lack of understanding
> of how both systems work and how one conducts repeatable experiments
> to quantify and qualify results.
>
> Take it from someone who has written dozens of test plans and
> spent a goodly part of a career in a screen-room, the "results"
> from their tests had no scientific validity. Now, that's not
> to say that their conclusion was incorrect . . . I've done a LOT
> of testing of equipment that was radiated strongly by sources
> that cover the cell phone frequencies and found no effect on
> the equipment under test. Indeed, that's a design goal of the
> supplier and a requirement for certification. Suffice it to say
> that squirting a bit of RF around the cockpit while watching to
> see if anything twitches is not a noteworthy test . . . I WISH
> it were so simple. Could have save my bosses $millions$.
>
> Bob . . .
>
>
Message 16
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--> AeroElectric-List message posted by: Dj Merrill <deej@deej.net>
Dave Morris "BigD" wrote:
>
>I agree that the mythbusters have strayed and nowadays most of their
>shows are mostly entertainment, with little real scientific evidence
>to back up their "busted / not busted" binary logic.
>
>
>
What, you mean proving you can't die from your own farts in a sealed
room wasn't scientific? *wink* :-)
-Dj
--
Dj Merrill
Glastar Sportsman 2+2 Builder #7118
http://econ.duke.edu/~deej/sportsman/
"Many things that are unexplainable happen during the construction of an
airplane." --Dave Prizio, 30 Aug 2005
Message 17
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| Subject: | Endurance Bus Diode & Voltage leak |
--> AeroElectric-List message posted by: "John Brick" <jebrick@comcast.net>
Another source of voltage to the main bus, with the master (and alternator
field) off, is the alternator when the engine is running. There is enough
residual magnetism or something...at least on my L-40 alternator, to produce
about 3.5 volts at high rpm and about half a volt at low rpm. This is with
minimal load on the bus. Significance in my case was that a shunt relay
powered by the main bus would not unlatch in flight when the Bat/Alt switch
was turned off, but it would on the ground at idle.
jb
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Robert L.
Nuckolls, III
Sent: Friday, March 31, 2006 8:40 AM
Subject: Re: AeroElectric-List: Endurance Bus Diode & Voltage leak
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<nuckollsr@cox.net>
At 10:40 AM 3/31/2006 -0500, you wrote:
>--> AeroElectric-List message posted by: sjhdcl@kingston.net
>
>Bob,
>
>Is it normal for a diode to leak voltage back onto the MAIN bus?
>
>With the EBus X Feed Switch on (no MAIN bus) it get 12.8V at the Endurance
>bus and about 6.85 V at the MAIN bus terminal. With the MASTER Off.
>
>I understand the forward voltage drop when the MAIN bus is powered and I
>measured it to be 0.6V. But I can't find any reference to this backwards
>'leak' of voltage by the diode.
>
>The diode is the standard 1" by 1" block (D-25) from B&C.
Diodes are not 'perfect' . . . they have forward voltage drop
and reverse leakage. Keep in mind that the input impedance of
a digital voltmeter is on the order of 10-20 MEGohms. To get
a reading of 6.85 volts due to leakage, you need only
6.85/10,000,000 or 685 NANOamps. If you turn on any single load
on the main bus, the reading will drop like a stone.
I went to the bench and wired a Fluke multimeter, 12v supply
and several diodes in series with a voltage measurement crafted
to show the effects of diode reverse leakage. From a selection
of parts in the bins, I got reverse leakage voltage readings from
.3 to 7.5 volts on regulator power silicon junction diodes.
When I measured a Shottky device, the leakage reading was 12V! I put
a 10,000 ohm load across the voltmeter and the reading dropped to
.25 volts. This shows that Shottky device leakage is several orders
of magnitude greater than for silicon junctions.
Bottom line is that your readings are understandable and not
significant in the grand scheme of things.
>Another question: Some diagrams show only attaching 2 of the tabs on the
>diode. One to Endurance and one to MAIN.
>
>Other diagram shows joining the two terminal on the diode and then going
>to the Endurance Bus. Is this for redundancy since these 2 terminals are
>electrically the same?
The four diodes contained in a bridge rectifier are identical.
If you noodle out their position in the device, you can use any
of 4 combinations of terminals to effect the desired operation.
But you can't go wrong with wiring per:
http://www.aeroelectric.com/Pictures/Wiring_Technique/diode_wiring.jpg
http://www.aeroelectric.com/Pictures/Misc/s401-25.jpg
Bob . . .
Message 18
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--> AeroElectric-List message posted by: "Lloyd, Daniel R." <LloydDR@wernerco.com>
That one was flawed in the sense the did one element at a time, and not
all of them at once. But regardless, I know many people who have body
odors I would not want to be sealed in with!
The one I found cool, was when they replicated the Australian airplane
accident when the prop chewed up the tail and fuse of the plane. In the
beginning the did not believe you could prop start and airplane...it
went downhill from there!
Dan
Definitely Do not archive
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Dj
Merrill
Sent: Friday, March 31, 2006 12:41 PM
Subject: Re: AeroElectric-List: Re: Cell phone
--> AeroElectric-List message posted by: Dj Merrill <deej@deej.net>
Dave Morris "BigD" wrote:
>
>I agree that the mythbusters have strayed and nowadays most of their
>shows are mostly entertainment, with little real scientific evidence
>to back up their "busted / not busted" binary logic.
>
>
>
What, you mean proving you can't die from your own farts in a sealed
room wasn't scientific? *wink* :-)
-Dj
--
Dj Merrill
Glastar Sportsman 2+2 Builder #7118
http://econ.duke.edu/~deej/sportsman/
"Many things that are unexplainable happen during the construction of an
airplane." --Dave Prizio, 30 Aug 2005
Message 19
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--> AeroElectric-List message posted by: "Jim Baker" <jlbaker@msbit.net>
do not archive
Jim Baker
580.788.2779
Elmore City, OK
Message 20
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| Subject: | Re: thermocouple wires |
--> AeroElectric-List message posted by: David <ainut@hiwaay.net>
I would.
David M.
Gary Casey wrote:
> --> AeroElectric-List message posted by: Gary Casey <glcasey@adelphia.net>
>
> Cold junction compensation: I have a system from Grand Rapids
> Technology that recommends using ThermoCouple(TC) wire all the way
> from the box to the TC connectors on the engine. The CHT uses type J
> and the EGT type K. The people that did my panel used copper to a
> bulkhead connector (expensive Mil-spec with gold-plated terminals)
> and then I, without too much thinking, kept going with copper wire to
> each TC connector. Now I'm worried about the errors will occur
> because of all the wire material mismatch. The only good thing going
> is that the TC wires are equal length so the + and - connectors are
> right next to each other. Big errors? Small errors? I'm almost
> tempted to pull out the whole thing, bulkhead connector and all, and
> run TC wire in one length from the box to each TC. I looked at the
> JPI system in my certified aircraft and that's the way it was done.
> And then while I'm at it I could buy real TC connectors that will
> keep all the materials correct. Should I?
>
> Gary Casey
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
Message 21
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| Subject: | Questions for Bob N. April 1, 2006 |
--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
1) The way to understand electricity is this: Everything in the
universe is made of male and female energies. Energy is being renewed,
flowing into mass, all the time. Rotation separates male from female. The
center remains still--no action, no motion, no force. That is YIN. That is
FEMALE. The outer edge (of a rotating mass), turns---action, motion, force.
This is MALE, or YANG. "Men and women are not opposites; we are at once both
yin and yang. Magnets polarize the male and female energies, thereby
creating electricity. Is that right?
2) I was thinking about this the other day and wondering. I have an IQ
of 175, which is high, but at school I get just average grades (i.e. some
B's and C's but mostly D's). Whereas my friend who has an IQ of only 100 is
getting A's and B plusses and dating cheerleaders, especially Louise Thomas
who is really cute. I try hard at school to memorize stuff for tests and
stuff, but I'm not sure. An IQ is your measure of intelligence right? Or is
it? I'm confused. Can you explain it? I know you're smart so I hope this is
the right forum to post this in.
3) I have an idea for a really neat insect catcher, but first I need
to know: Can bats see an F117?
4) What is this "String Theory" stuff about? Is this a NASA thing?
Q. Why do aircraft builders scratch themselves when working with glass
fiber?
A: Because they are the only ones who know where it itches!
(do not archive)
Message 22
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| Subject: | Re: Questions for Bob N. April 1, 2006 |
--> AeroElectric-List message posted by: "Matt Prather" <mprather@spro.net>
Hello Eric,
Like usual, you are ahead of your time.. :)
Matt-
do not archive
> --> AeroElectric-List message posted by: "Eric M. Jones"
> <emjones@charter.net>
>
> 1) The way to understand electricity is this: Everything in the
> universe is made of male and female energies. Energy is being renewed,
> flowing into mass, all the time. Rotation separates male from female.
> The center remains still--no action, no motion, no force. That is YIN.
> That is FEMALE. The outer edge (of a rotating mass), turns---action,
> motion, force. This is MALE, or YANG. "Men and women are not opposites;
> we are at once both yin and yang. Magnets polarize the male and female
> energies, thereby creating electricity. Is that right?
> 2) I was thinking about this the other day and wondering. I have
> an IQ of 175, which is high, but at school I get just average grades
> (i.e. some B's and C's but mostly D's). Whereas my friend who has an IQ
> of only 100 is getting A's and B plusses and dating cheerleaders,
> especially Louise Thomas who is really cute. I try hard at school to
> memorize stuff for tests and stuff, but I'm not sure. An IQ is your
> measure of intelligence right? Or is it? I'm confused. Can you explain
> it? I know you're smart so I hope this is the right forum to post this
> in.
> 3) I have an idea for a really neat insect catcher, but first I
> need to know: Can bats see an F117?
> 4) What is this "String Theory" stuff about? Is this a NASA thing?
>
> Q. Why do aircraft builders scratch themselves when working with glass
> fiber?
> A: Because they are the only ones who know where it itches!
>
> (do not archive)
>
>
Message 23
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| Subject: | Questions for Bob N. April 1, 2006 |
--> AeroElectric-List message posted by: "Richard Riley" <richard@riley.net>
Eric M. Jones <emjones@charter.net> wrote:
>3) I have an idea for a really neat insect catcher, but first I need
to know: Can bats see an F117?
No. See Aviation Week and Space Technology Oct 17, 1991
"An acoustic-guided submunition call the BAT may be good against tanks, but not
against an F-117. A reader who works on the stealth fighter in Saudi Arabia says
bats (the natural ones) occasionally work their way into F-117 hangars. One
night, a hungry bat turned right into an F-117 rudder and fell stunned to the
floor. He flew away groggily, leaving behind a heightened impression of the
aircraft's stealth. "I don't know what the radar return is for the vertical tails
of the F-117 but I always thought it had to be more than an insect's," the
reader said. "I guess I was wrong." There may be some "science" in this - the
ultrasound wavelengths used by bats are roughly the same as X-band radar. "
Message 24
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| Subject: | Questions for Bob N. April 1, 2006 |
--> AeroElectric-List message posted by: "John W. Cox" <johnwcox@pacificnw.com>
Eric keep up the pondering. Sex, insects and life are all intertwined.
I have a friend who invented a Fruit Fly trap while ponder the same
dilemma. He is doing quite well. Keep up the inventions. It all helps
our aircraft passions to fly like a bat and be invisible to Homeland
Security F117s.
John Cox
Do not Archive
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Eric
M. Jones
Sent: Friday, March 31, 2006 2:21 PM
Subject: AeroElectric-List: Questions for Bob N. April 1, 2006
--> AeroElectric-List message posted by: "Eric M. Jones"
<emjones@charter.net>
1) The way to understand electricity is this: Everything in the
universe is made of male and female energies. Energy is being renewed,
flowing into mass, all the time. Rotation separates male from female.
The
center remains still--no action, no motion, no force. That is YIN. That
is
FEMALE. The outer edge (of a rotating mass), turns---action, motion,
force.
This is MALE, or YANG. "Men and women are not opposites; we are at once
both
yin and yang. Magnets polarize the male and female energies, thereby
creating electricity. Is that right?
2) I was thinking about this the other day and wondering. I have
an IQ
of 175, which is high, but at school I get just average grades (i.e.
some
B's and C's but mostly D's). Whereas my friend who has an IQ of only 100
is
getting A's and B plusses and dating cheerleaders, especially Louise
Thomas
who is really cute. I try hard at school to memorize stuff for tests and
stuff, but I'm not sure. An IQ is your measure of intelligence right? Or
is
it? I'm confused. Can you explain it? I know you're smart so I hope this
is
the right forum to post this in.
3) I have an idea for a really neat insect catcher, but first I
need
to know: Can bats see an F117?
4) What is this "String Theory" stuff about? Is this a NASA thing?
Q. Why do aircraft builders scratch themselves when working with glass
fiber?
A: Because they are the only ones who know where it itches!
(do not archive)
Message 25
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| Subject: | Re: Questions for Bob N. April 1, 2006 |
--> AeroElectric-List message posted by: David <ainut@hiwaay.net>
If true, now that is some cool info!
David M.
Richard Riley wrote:
> --> AeroElectric-List message posted by: "Richard Riley" <richard@riley.net>
>
> Eric M. Jones <emjones@charter.net> wrote:
>
>
>>3) I have an idea for a really neat insect catcher, but first I need
>
> to know: Can bats see an F117?
>
>
> No. See Aviation Week and Space Technology Oct 17, 1991
>
> "An acoustic-guided submunition call the BAT may be good against tanks, but not
against an F-117. A reader who works on the stealth fighter in Saudi Arabia
says bats (the natural ones) occasionally work their way into F-117 hangars.
One night, a hungry bat turned right into an F-117 rudder and fell stunned to
the floor. He flew away groggily, leaving behind a heightened impression of the
aircraft's stealth. "I don't know what the radar return is for the vertical
tails of the F-117 but I always thought it had to be more than an insect's," the
reader said. "I guess I was wrong." There may be some "science" in this - the
ultrasound wavelengths used by bats are roughly the same as X-band radar. "
>
>
Message 26
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| Subject: | Re: Questions for Bob N. April 1, 2006 |
--> AeroElectric-List message posted by: "Dave Morris \"BigD\"" <BigD@DaveMorris.com>
I don't know, but the infrared auto-focus of my automatic camera
couldn't lock onto one either at the air show. The pilot standing
there just smiled and said "your tax dollars at work".
Dave Morris
At 04:21 PM 3/31/2006, you wrote:
>--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
>
>3) I have an idea for a really neat insect catcher, but first I need
>to know: Can bats see an F117?
Message 27
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| Subject: | Re: Questions for Bob N. April 1, 2006 |
--> AeroElectric-List message posted by: "William Yamokoski" <yamokow@gmail.com>
>3) I have an idea for a really neat insect catcher, but first I need
> >to know: Can bats see an F117?
>
>
> Fellas, fellas, fellas.... Most bats can see an F117 as well as you and I
> can. Tsk, tsk. They have eyes you know!
> Most bats echolocate using frequency modulation in the 20-200 kilohertz
> range, although some use <20khtz so are audiible to us. What they can't do
> well is process target texture and density information that hasn't been
> previoulsy mapped either by an individual or by the group. Bats frequently
> run into large man-made objects when placed in an entirely new articifial
> environment, e.g., a hangar. Desert bats don't have a whole lot of
> experience with airports, I guess. Sheesh...di I have to explain everything
> :)
Bill Yamokoski, advising not to land yout plane in a cornfield in August
>
>
Message 28
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| Subject: | Dead face Annunciators |
--> AeroElectric-List message posted by: <rparigor@suffolk.lib.ny.us>
We were fooling with some 5/8" square LEDs tonight. They have 2 or 3 LEDs
potted and a flat face. We wanted to cover them with a label and use them
for a dead face annunciator. Just not bright enough. OK for night, but not
day.
After a bit of fooling and thinking we somehow managed to find ourselves
at the checkout line of Home Depot with a "Egg Crate" style Chrome plated
piece of plastic diffuser for a dropped ceiling.
We are planning on putting 2 or more LEDs in each 5/8" square, mounted to
a higher quality through plated breadboard. Probably 12 Annunciators
driven by a IL12A:
http://www.vx-aviation.com/page_2.html#IL-4A,%20IL-12A_more
Panel is .090" thick. Will make a through hole the ID of two high by 6
wide, then mill a pocket ~.070" deep the OD of 2 x 6. Idea is to first
drop in printed or engraved face, then the Egg Crate over that and redux
it to the panel.
Any suggestions on above?
Any suggestions on how to make labeling? Thin engraved black over white?
P-Touch?
Other?
Thx.
Ron Parigoris
Message 29
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| Subject: | Re: Dead face Annunciators |
--> AeroElectric-List message posted by: Mickey Coggins <mick-matronics@rv8.ch>
> We were fooling with some 5/8" square LEDs tonight. They have 2 or 3 LEDs
> potted and a flat face. We wanted to cover them with a label and use them
> for a dead face annunciator. Just not bright enough. OK for night, but not
> day.
I bought some 40,000 mcd white LEDs from http://www.besthongkong.com/
and they are very bright. Hurt your eyes, bright. Perhaps you can
swap out the LEDs?
>
> Any suggestions on above?
> Any suggestions on how to make labeling? Thin engraved black over white?
> P-Touch?
> Other?
I basically copied Paul's annunciator panel design:
http://www.vansairforce.com/community/showthread.php?t=5197
His idea of printing your labels with colors right onto
a transparency (presentation foil, think before powerpoint)
worked great.
--
Mickey Coggins
http://www.rv8.ch/
#82007 finishing
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