Today's Message Index:
----------------------
1. 07:14 AM - Touchy (Joe)
2. 08:24 AM - Re: Touchy (rayj)
3. 08:27 AM - Re: Fusible links (Robert L. Nuckolls, III)
4. 09:16 AM - Toroid beads VOR antenna vs. Active VOR antenna (Robert L. Nuckolls, III)
5. 09:17 AM - Re: Fusible links (Charlie England)
6. 10:04 AM - =?utf-8?Q?Re:__Fusible_links? ()
7. 11:20 AM - Re: Fusible links (Robert L. Nuckolls, III)
8. 12:19 PM - =?utf-8?Q?Re:__Fusible_links? ()
9. 02:02 PM - Always on supply (donjohnston)
10. 02:15 PM - Re: Fusible links (Robert L. Nuckolls, III)
11. 02:56 PM - Re: Fusible links (B Tomm)
12. 04:24 PM - Re: Re: Touchy (Bill Bradburry)
13. 07:10 PM - Re: Fusible links (Lyle Peterson)
14. 08:53 PM - Re: Fusible links (B Tomm)
15. 09:22 PM - Sending two msgs to the list (Bill Bradburry)
Message 1
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There is an old saying, "Beggars can't be choosy." That applies to the
AeroElectric List where replies are posted by volunteers. If I
volunteered to help someone who then complained about my work, I would
stop giving help. There is one very knowledgeable volunteer on the
AeroElectric list who sometimes gives long winded and philosophical
responses. Sometimes his response answers my question and sometimes
not. Regardless, I appreciate it that he has volunteered his precious
time to address my issue. There are many other participants on this
forum who are also very knowledgeable. Some of them might not post a
response to a question because they are afraid of getting flamed. So
please treat everyone with respect. Do not post something that you
would not say face to face. As for a question not being answered, maybe
the question needs to be rephrased or needs to be more specific.
Joe Gores
Message 2
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Test, please ignore.
do not archive
--
Raymond Julian
Kettle River, MN
The things we admire in men, kindness and generosity, openness, honesty,
understanding and feeling are the concomitants of failure in our system.
And those traits we detest, sharpness, greed, acquisitiveness, meanness,
egotism and self-interest are the traits of success. And while men
admire the quality of the first they love the produce of the second.
-John Steinbeck, novelist, Nobel laureate (1902-1968)
Message 3
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At 15:53 2014-12-02, you wrote:
Thanks Bob,
I had done it on mine a couple years back, but the other day I was
helping a hangar neighbour make some improvements. He has a rear
mounted battery on a BD4 (engine in front). He has one electronic
ignition which was powered by an 18 awg wire connected on the
firewall at the input power terminal at the starter solenoid. This
fat wire was only powered when the master solenoid (located in back
next to the battery) was active. Not ideal for electrically
dependant ignition. There was a spare 18 awg wire already running
all the way back to the battery and the owner wanted to use that. I
suggested that we fuse it but that fuse would have to
activate "slower" than the breaker on the panel. I therefore
suggested a fusible link and that is where I crossed the line. Since
it was such a good idea, and I had suggested it, it was suggested
that I do it :) Not a problem since I had materials left
over. Just couldn't remember if the 22awg wire (now hidden under the
silicone impregnated sleeve) on my RV7 had been stripped or not. My
thinking initially was that it must have been stripped because we
really don't want any combustible material "inside" the fuse if
possible. It didn't strip well, so I re-did it without stripping as
you have confirmed. Thank you.
Okay, this is a situation similar
to the "bus extension" to panel mounted
breaker for a crowbar ov protection
system.
Keep in mind that circuit protection is
to keep the smoke in wires. Further, the
'rule of thumb' for always hot wires from
a battery bus is to protect at 5A or less
Given that fuses are MUCH faster than
breakers . . . 7A fuse is a comfortable
alternative to the 5A breaker.
This is a convention driven by concerns
for crash safety. Limit the energy available
on an always-hot wire for the purposes of
reducing risk of post crash fire. I don't
believe for a minute that anyone did any
tests combined with statistical analysis
to come up with that 5A number . . . but
intuitively, one finds comfort in protecting
an always-hot wire at the lowest practical
value.
I suspect that the electronic ignition runs
on MUCH less than 5A. What size is the panel
mounted breaker? If it were my airplane,
I'd drive the ignition supply wire from the
battery through a 7A fuse and eliminate the
panel mounted breaker.
If that breaker EVER trips, then there's
something seriously wrong with either
the ignition system or the power pathway
feeding it . . . the notion of resetting it
is does not stand on favorable probabilities
for recovery-by-reset. A 7A fuse, 5A breaker,
or fusible link in the tail does not alter
the probabilities . . .
Bob . . .
Message 4
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Subject: | Toroid beads VOR antenna vs. Active VOR antenna |
>
>
>All perfectly doable. I just need to get a better understanding of
>the necessities of your request.
>
>Thanks again,
>James
Understand. My current vision of this antenna suggests
that it will look like a piece of RG coax with a little
"lump" of a splice onto a 6-inch piece of wire. The
'lumpy splice' will contain a handful of components that
allows the relatively poor antenna to deliver energy into
the 50-ohm coax (end impedance of too-short element is
WAAayyyy to high).
A little background:
Active antennas have been around for a long time.
Adding some form of amplifier with a high input
impedance to the antenna-end of a low impedance
coax allows the 'crippled' but still quite serviceable
antenna to deliver its energy into the low impedance
feed line.
Here are some examples:
http://tinyurl.com/npdmnsw
In particular, I'll call your attention to one
of many versions described. Check out the
"AA7" . ..
Active Antenna AA-7 HF/VHF/UHF, 3-3000MHz
It has an HF, VHF 'band' switch. You'll note that
in the VHF position, the active circuitry consists
of the single transistor and a couple of passive
components. The circuit I posted earlier . . .
Emacs!
was an adaptation of the AA7 configuration. Most
active antenna designs bring rf energy down the
feed line and send dc power up to the antenna
on the same feed line. I decided to keep coax
installation as pristine as possible and not
mess with the feed line after it leaves the antenna.
So, the ready-to-install antenna assembly
takes on the form described above where you
hopefully will be able to offer a conduit through
which the antenna can be extended into the wing.
To eliminate the 'monkey motion' at the
receiver end of the coax, dc power will have
to be brought out to the amplifier on a
separate, 22 awg wire that can be fed from
the same breaker as the radio . . .
The ferrite transformer cores came in last
week. I need to brass-board this thing
on the bench and verify performance before I
squish it down into that 'lump' described earlier.
An interesting and important feature of this
experiment is to not glass the critter into
place so that any future fiddling with the
design doesn't take a hack saw to the airplane.
I may mount one of this things on my roof and
see how it compares with monitor antennas I
have for listening to local city, police and
fire services.
I have one HF active antenna up there already.
http://tinyurl.com/ou2ezdy
The 'antenna' part of this critter is only a
few inches long. I don't have any other HF
optimized antennas up yet to compare it to . . .
but this 'lump' on the end of a piece of coax
hears 'lots of stuff'. Given that the 'stuff'
of which VOR is made (high power, line of sight)
it seems that our little experiment has a high
probability of success for replacing the legacy
dipoles and whiskers so favored by our TC
brothers.
Bob . . .
Message 5
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Subject: | Re: Fusible links |
On 12/3/2014 10:26 AM, Robert L. Nuckolls, III wrote:
> <nuckolls.bob@aeroelectric.com>
>
>
> At 15:53 2014-12-02, you wrote:
> Thanks Bob,
>
> I had done it on mine a couple years back, but the other day I was
> helping a hangar neighbour make some improvements. He has a rear
> mounted battery on a BD4 (engine in front). He has one electronic
> ignition which was powered by an 18 awg wire connected on the firewall
> at the input power terminal at the starter solenoid. This fat wire was
> only powered when the master solenoid (located in back next to the
> battery) was active. Not ideal for electrically dependant ignition.
> There was a spare 18 awg wire already running all the way back to the
> battery and the owner wanted to use that. I suggested that we fuse it
> but that fuse would have to activate "slower" than the breaker on the
> panel. I therefore suggested a fusible link and that is where I
> crossed the line. Since it was such a good idea, and I had suggested
> it, it was suggested that I do it :) Not a problem since I had
> materials left over. Just couldn't remember if the 22awg wire (now
> hidden under the silicone impregnated sleeve) on my RV7 had been
> stripped or not. My thinking initially was that it must have been
> stripped because we really don't want any combustible material
> "inside" the fuse if possible. It didn't strip well, so I re-did it
> without stripping as you have confirmed. Thank you.
>
> Okay, this is a situation similar
> to the "bus extension" to panel mounted
> breaker for a crowbar ov protection
> system.
>
> Keep in mind that circuit protection is
> to keep the smoke in wires. Further, the
> 'rule of thumb' for always hot wires from
> a battery bus is to protect at 5A or less
> Given that fuses are MUCH faster than
> breakers . . . 7A fuse is a comfortable
> alternative to the 5A breaker.
>
> This is a convention driven by concerns
> for crash safety. Limit the energy available
> on an always-hot wire for the purposes of
> reducing risk of post crash fire. I don't
> believe for a minute that anyone did any
> tests combined with statistical analysis
> to come up with that 5A number . . . but
> intuitively, one finds comfort in protecting
> an always-hot wire at the lowest practical
> value.
>
> I suspect that the electronic ignition runs
> on MUCH less than 5A. What size is the panel
> mounted breaker? If it were my airplane,
> I'd drive the ignition supply wire from the
> battery through a 7A fuse and eliminate the
> panel mounted breaker.
>
> If that breaker EVER trips, then there's
> something seriously wrong with either
> the ignition system or the power pathway
> feeding it . . . the notion of resetting it
> is does not stand on favorable probabilities
> for recovery-by-reset. A 7A fuse, 5A breaker,
> or fusible link in the tail does not alter
> the probabilities . . .
>
>
> Bob . . .
Probably a safe assumption for 'traditional' a/c engines with stock fuel
delivery, but different for 'alternative' (automotive-based) engines and
increasingly, a/c engines, more current is required. Most
automotive-based engines use high pressure fuel injection which must be
included in current calculations. There's now a growing wave of
automotive style injection on a/c engines, as well. High pressure
gerotor or roller-vane fuel pumps typically draw 6-10 amps continuous.
Even the little turbine style pumps (which must be installed inside the
fuel tank; the input must be kept flooded) typically draw 3-4 amps. So
total current demand to keep an 'electronic' engine running usually
exceeds 10 amps; often as high as 15.
So what's the solution? Dedicated fuse bus at the battery to distribute
power to the various engine control components?
Charlie
Message 6
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Subject: | Re:_AeroElectric-List:_Fusible_links? |
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ZS4NCg0KDQpSb2dlcg=
Message 7
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Subject: | Re: Fusible links |
Probably a safe assumption for 'traditional' a/c engines with stock
fuel delivery, but different for 'alternative' (automotive-based)
engines and increasingly, a/c engines, more current is required. Most
automotive-based engines use high pressure fuel injection which must
be included in current calculations. There's now a growing wave of
automotive style injection on a/c engines, as well. High pressure
gerotor or roller-vane fuel pumps typically draw 6-10 amps
continuous. Even the little turbine style pumps (which must be
installed inside the fuel tank; the input must be kept flooded)
typically draw 3-4 amps. So total current demand to keep an
'electronic' engine running usually exceeds 10 amps; often as high as 15.
So what's the solution? Dedicated fuse bus at the battery to
distribute power to the various engine control components?
He was talking about an ignition system. Energy
to light the fires is quite nominal. Not aware of
any ignition that requires more than 3A. Lightspeed's
flame throwing CD ignition runs 2.6A at 2700 rpm on
a 6 cyl engine.
Fuel delivery is another matter and, as you've noted,
can be all over the map. TBI systems run on a few amps
while some 40+ psi rail fed injector systems can be
MUCH higher.
I'd treat this like the heavy duty e-bus feeder
illustrated in Z-32 . . . except the e-bus alt feed
switch becomes a fuel system control switch. The
relay could be a solid state device or one of the
sealed electro-mechanical critters.
This comports nicely with the TC aircraft philosophy
for achieving a Max-Cold state of all wires when
crew operated switches are placed to OFF.
Bob . . .
Message 8
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Subject: | Re:_AeroElectric-List:_Fusible_links? |
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Message 9
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Subject: | Always on supply |
The GPS manufacturer suggests connecting a second, always on, supply (they call
it "clock power") which will improve GPS position acquisition time.
What is the preferred way of providing this power? Run a fused line (they recommend
a .1a fuse) directly from a battery terminal (or battery side of the master
solenoid) to the GPS?
IIRC, the EFIS would like one of these always on supplies also.
So maybe run a fused wire from the battery to the panel and create an "always
on" bus with fused branches off of that?
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=435279#435279
Message 10
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Subject: | Re: Fusible links |
At 14:08 2014-12-03, you wrote:
> Not aware of
> any ignition that requires more than 3A. Lightspeed's
> flame throwing CD ignition runs 2.6A at 2700 rpm on
> a 6 cyl engine.
>
>
>If you are using a PSRU (propeller speed reduction unit) on a 6
>cylinder engine you will have a higher engine RPM, perhaps in the
>range of 4 - 5 k rpm. This higher speed will translate to a higher
>current flow to the electronic CD ignition. An MSD 6A automotive CD
>ignition module is specified at 1A / 1K RPM, which translates to
>perhaps 5A worst case.
Hmmmm . . . that's too bad. There's no good reason
for ignition systems to draw that much current.
I've talked with the guys at EmagAir about this
several times. A take-away from those conversations
says that it's most important to get an adequate spark
delivered right on time. Magnetos have proven their
ability to deliver adequate sparks while running . . .
and they're certainly not flame throwers. Certainly
hard to fiddle with the timing . . . and you need
some kind of monkey motion like impulse couplers or
shower-of-sparks to effect nice starts . . . but
there's hundreds of thousands flying with few
critical issues.
Being able to advance the spark at low manifold
pressures gets you some benefit . . .but the spark
doesn't need to be any hotter . . . in fact, worst
case sparking requirements are at max cylinder pressure
which probably means a boosted engine at max retard
timing.
The legacy Kettering coil, condenser, points system
delivers about 30-40 mJ per spark. For a 6-cyl engine
running 2400 rpm, 40 rev/sec, 3 sparks per rev, energy
at the plugs comes to about 120 mJ per rev or 4800
mJ per second. Assume a really lousy system efficiency
of say 50% and we need to draw 9.6 watts from the
ship's bus or about 700 mA.
Now, deliver that energy even while cold and with
a soggy battery . . . and be able to advance the
timing at low manifold pressures, and you've got
a perfectly adequate ignition system.
So be curious and skeptical when someone says
their 'flame throwing ignition system' is going
to do great things for your airplane. If you're
flying a racer, maybe. If you've got a nice
point-a to point-b transportation machine that
carries battery energy to implement Plan-B, perhaps
all that flame at the spark plugs suggests a
need to re-think the planning.
Elegant solutions benefit from good stewardship
of energy. It starts with the airfoils and
extends down to batteries and fuel aboard.
Bob . . .
Message 11
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Thanks Bob,
The literature that came with the LightSpeed says the breaker should be 7.5
amp. (IO-540) You still recommend a 5 amp breaker (since he really wants
some form of disconnect on the panel) and a (??? Value fuse, fusible link,
breaker)at the rear for the feed from the battery.
Perhaps I should suggest a 5 or 7.5 amp slow blo fuse at the battery, and a
simple switch on the panel in place of the breaker if he must have a
disconnect.
Bevan
-----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, December 03, 2014 8:27 AM
Subject: RE: AeroElectric-List: Fusible links
--> <nuckolls.bob@aeroelectric.com>
At 15:53 2014-12-02, you wrote:
Thanks Bob,
I had done it on mine a couple years back, but the other day I was helping a
hangar neighbour make some improvements. He has a rear mounted battery on a
BD4 (engine in front). He has one electronic ignition which was powered by
an 18 awg wire connected on the firewall at the input power terminal at the
starter solenoid. This fat wire was only powered when the master solenoid
(located in back next to the battery) was active. Not ideal for
electrically dependant ignition. There was a spare 18 awg wire already
running all the way back to the battery and the owner wanted to use that. I
suggested that we fuse it but that fuse would have to activate "slower"
than the breaker on the panel. I therefore suggested a fusible link and
that is where I crossed the line. Since it was such a good idea, and I had
suggested it, it was suggested
that I do it :) Not a problem since I had materials left
over. Just couldn't remember if the 22awg wire (now hidden under the
silicone impregnated sleeve) on my RV7 had been stripped or not. My
thinking initially was that it must have been stripped because we really
don't want any combustible material "inside" the fuse if possible. It didn't
strip well, so I re-did it without stripping as you have confirmed. Thank
you.
Okay, this is a situation similar
to the "bus extension" to panel mounted
breaker for a crowbar ov protection
system.
Keep in mind that circuit protection is
to keep the smoke in wires. Further, the
'rule of thumb' for always hot wires from
a battery bus is to protect at 5A or less
Given that fuses are MUCH faster than
breakers . . . 7A fuse is a comfortable
alternative to the 5A breaker.
This is a convention driven by concerns
for crash safety. Limit the energy available
on an always-hot wire for the purposes of
reducing risk of post crash fire. I don't
believe for a minute that anyone did any
tests combined with statistical analysis
to come up with that 5A number . . . but
intuitively, one finds comfort in protecting
an always-hot wire at the lowest practical
value.
I suspect that the electronic ignition runs
on MUCH less than 5A. What size is the panel
mounted breaker? If it were my airplane,
I'd drive the ignition supply wire from the
battery through a 7A fuse and eliminate the
panel mounted breaker.
If that breaker EVER trips, then there's
something seriously wrong with either
the ignition system or the power pathway
feeding it . . . the notion of resetting it
is does not stand on favorable probabilities
for recovery-by-reset. A 7A fuse, 5A breaker,
or fusible link in the tail does not alter
the probabilities . . .
Bob . . .
Message 12
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I was being "cute" with the uninteresting comment, Bob.
I suspect that everything on the list is interesting to someone on the list,
although maybe not to everybody on the list. I think I get something even
from the posts that I don't quite understand and for sure from the posts
counseling the need for something someone wants to do. Sometimes I agree
and sometimes not, but an opinion not your own can sometimes turn on a light
bulb.
When my questions get ignored I just assume that no one reading that day has
a suggestion that he feels strongly about enough to post. It is
disappointing though, when you really kinda want a suggestion and don't get
anything and then some fairly basic thing will get 10 hits. :>)
But I am not criticizing the list, because God knows, I am flying an
airplane the parts of which would still be scattered all over the hangar if
it had not been for the good and generous graces if Bob N. and the others on
this list.
Bill
_____
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert
Borger
Sent: Tuesday, December 02, 2014 9:15 AM
Subject: Re: AeroElectric-List: Re: Touchy
Bill,
I understand your unanswered requests for help. It's not that they are
uninteresting. It's because I don't have an answer and I don't want to be
one of the ones cluttering up the list with speculation or proposing
alternatives you don't need.
Blue skies & tailwinds,
Bob Borger
Europa XS Tri, Rotax 914, Airmaster C/S Prop (75 hrs).
Little Toot Sport Biplane, Lycoming Thunderbolt AEIO-320 EXP
3705 Lynchburg Dr.
Corinth, TX 76208-5331
Cel: 817-992-1117
<mailto:rlborger@mac.com> rlborger@mac.com
On Dec 2, 2014, at 8:13 AM, Bill Bradburry <bbradburry@verizon.net> wrote:
Stan,
Very well said. A similar problem with the list is when there is no
response at all. This happens to me quite frequently. I suppose it would
help if I had more interesting problems. :>)
Bill
Message 13
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Subject: | Re: Fusible links |
Hi,
I've been involved in electronics for some 30 years. I know what a
fusible link is in an automobile. They do come in a variety of designs,
some very much like a fuse as we know them.
I have always questioned the value of a fusible link such as is used in
automobiles. They are a length of wire, usually 4 wire gauges smaller
than the wire they are protecting. They are most often a hassle to
replace. Why would not a common fuse perform the same function and be
much more easily replaced?
Inquiring minds want to know,
Lyle
On 12/3/2014 4:14 PM, Robert L. Nuckolls, III wrote:
> <nuckolls.bob@aeroelectric.com>
>
> At 14:08 2014-12-03, you wrote:
>
>
>> Not aware of
>> any ignition that requires more than 3A. Lightspeed's
>> flame throwing CD ignition runs 2.6A at 2700 rpm on
>> a 6 cyl engine.
>>
>>
>> If you are using a PSRU (propeller speed reduction unit) on a 6
>> cylinder engine you will have a higher engine RPM, perhaps in the
>> range of 4 - 5 k rpm. This higher speed will translate to a higher
>> current flow to the electronic CD ignition. An MSD 6A automotive CD
>> ignition module is specified at 1A / 1K RPM, which translates to
>> perhaps 5A worst case.
>
>
--
Lyle
Sent from my Gateway E4610D desktop
Message 14
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The advantages of the fusible link in this case is:
Must be slower acting than the breaker. I blew quite a few fuses until I
found that I needed a fuse of about double the value to ensure the breaker
trips first. This would suggest a 15 amp fuse which is larger than desired.
Robust (although a fuse in an inline holder is equally suitable in this
regard.)
There's no place to mount a breaker near the battery where it is easily
accessible and yet not in the way for battery access through the small panel
where it is located.
Cost and availability. We're trying to get this airplane back in the air so
it can go home. They can make more permanent changes there.
Bevan
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Lyle
Peterson
Sent: Wednesday, December 03, 2014 7:08 PM
Subject: Re: AeroElectric-List: Fusible links
--> <lyleap@centurylink.net>
Hi,
I've been involved in electronics for some 30 years. I know what a fusible
link is in an automobile. They do come in a variety of designs, some very
much like a fuse as we know them.
I have always questioned the value of a fusible link such as is used in
automobiles. They are a length of wire, usually 4 wire gauges smaller than
the wire they are protecting. They are most often a hassle to replace. Why
would not a common fuse perform the same function and be much more easily
replaced?
Inquiring minds want to know,
Lyle
On 12/3/2014 4:14 PM, Robert L. Nuckolls, III wrote:
> <nuckolls.bob@aeroelectric.com>
>
> At 14:08 2014-12-03, you wrote:
>
>
>> Not aware of
>> any ignition that requires more than 3A. Lightspeed's
>> flame throwing CD ignition runs 2.6A at 2700 rpm on
>> a 6 cyl engine.
>>
>>
>> If you are using a PSRU (propeller speed reduction unit) on a 6
>> cylinder engine you will have a higher engine RPM, perhaps in the
>> range of 4 - 5 k rpm. This higher speed will translate to a higher
>> current flow to the electronic CD ignition. An MSD 6A automotive CD
>> ignition module is specified at 1A / 1K RPM, which translates to
>> perhaps 5A worst case.
>
>
--
Lyle
Sent from my Gateway E4610D desktop
Message 15
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Subject: | Sending two msgs to the list |
I seem to be sending two msgs to the list each time I post. I am using
Outlook. Does anyone know why this may be happening? It appears to have
started a couple of days ago. The msgs are about 12 minutes apart and I am
only hitting send one time. AFAIK it is only happening with msgs to the
Aeroelectric list.
Thanks for any ideas.
Bill
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