Today's Message Index:
----------------------
1. 05:10 AM - Bending a SS VOR antenna (whodja)
2. 06:00 AM - M27500 Shielded Wire For Strobe (William Hunter)
3. 06:48 AM - Re: M27500 Shielded Wire For Strobe (Robert L. Nuckolls, III)
4. 11:16 AM - Re: M27500 Shielded Wire For Strobe (William Hunter)
5. 12:45 PM - Re: 3PDT switch swap for relay? (user9253)
6. 02:45 PM - Re: M27500 Shielded Wire For Strobe (Robert L. Nuckolls, III)
7. 04:08 PM - Re: M27500 Shielded Wire For Strobe (William Hunter)
Message 1
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Subject: | Bending a SS VOR antenna |
Any recommendations on bending a SS VOR antenna? Based on a modified mount my antennas
come out of the mount at 90 and I would like to bend them to 45. Heat
or no heat?
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=466821#466821
Message 2
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Subject: | M27500 Shielded Wire For Strobe |
Greetings,
I am wiring a Velocity composite aircraft.
For my Whelen HDACF strobe light circuit I was planning on using the gold
colored copper strand lamp cord from Home Depot... just kidding... I am
actually planning on using Tefzel M22759/16 wire 18 guage from the CB to
the overhead switch and then from the switch way back to the strobe unit
mounted on the firewall (pusher airplane).
Then... I read "somewhere" that the M27500 Shielded wire is recommended for
this application so as to suppress the noise.
Is this really necessary?
THANKS!!!
Bill Hunter
Message 3
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Subject: | Re: M27500 Shielded Wire For Strobe |
At 07:58 AM 3/3/2017, you wrote:
>Greetings,=C2
>
>I am wiring a Velocity composite aircraft.=C2
>
>For my Whelen HDACF strobe light circuit I was
>planning on using the gold colored copper strand
>lamp cord from Home Depot... just kidding... I
>am actually planning on using Tefzel M22759/16
>wire 18 guage from the CB to the overhead switch
>and then from the switch way back to the strobe
>unit mounted on the firewall (pusher airplane).=C2
>
>Then... I read "somewhere" that the M27500
>Shielded wire is recommended for this
>application so as to suppress the noise.=C2
>
>Is this really necessary?=C2
Shielding of wires breaks only ONE kind
of noise propagation mode. This mode is very weak
and then only applies to certain kinds of
fast rising antagonists. No such antagonists exist
on the DC power line to any modern piece of
electronics . . . if it DOES demonstrate such
antagonists, then those will be CONDUCTED into
the rest of the system whether the wire is shielded
or not . . . short answer:
No
Bob . . .
Message 4
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Subject: | Re: M27500 Shielded Wire For Strobe |
Wow... Bob and Simon I am very grateful for your time. I cannot contribute
much back to this forum however on other forums where I have some tid bits
of ignorance to expound upon I try to help where I can so as to "cyber pay
it forward".
Yes it seemed odd to me to have to shield a DC supply wire to the power
inputs of a DC unit. Output wires from the strobe box to the strobe lights
on the wings could have a argument.
I will certainly twist the power feed wire pairs as suggested for this box.
I also have two Light Speed Plasma III ignition units and two aircraft
batteries. Since Klaus recommends running the POS and NEG wires directly
from the battery terminals (through a reset able CB) to the units I will
also twist those pairs.
My power feeds from the associated CB to the radios is a very small run and
there is no negative wire nearby to twist so I guess that is a wash.
I do have some other wires from DC CBs to switches and then to appliances
such as landing /taxi/beacon /voltage regulators and some of those wires
runs will be bundled next to the XPNDR /ADS-B /NAV/COM coaxial cables
(using the coaxial cable Bob recommended). I suppose the shield on the coax
will do the trick.
Bill Hunter
On Mar 3, 2017 09:56, "Robert L. Nuckolls, III" <
nuckolls.bob@aeroelectric.com> wrote:
> At 07:58 AM 3/3/2017, you wrote:
>
> Greetings,=C3=82
>
> I am wiring a Velocity composite aircraft.=C3=82
>
> For my Whelen HDACF strobe light circuit I was planning on using the gold
> colored copper strand lamp cord from Home Depot... just kidding... I am
> actually planning on using Tefzel M22759/16 wire 18 guage from the CB to
> the overhead switch and then from the switch way back to the strobe unit
> mounted on the firewall (pusher airplane).=C3=82
>
> Then... I read "somewhere" that the M27500 Shielded wire is recommended
> for this application so as to suppress the noise.=C3=82
>
> Is this really necessary?=C3=82
>
>
> Shielding of wires breaks only ONE kind
> of noise propagation mode. This mode is very weak
> and then only applies to certain kinds of
> fast rising antagonists. No such antagonists exist
> on the DC power line to any modern piece of
> electronics . . . if it DOES demonstrate such
> antagonists, then those will be CONDUCTED into
> the rest of the system whether the wire is shielded
> or not . . . short answer:
>
> No
>
>
> Bob . . .
>
Message 5
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Subject: | Re: 3PDT switch swap for relay? |
Cozy Nose Gear circuit is attached. I do not have a Cozy.
If switch is in "UP" position and airspeed is greater than 40 and less than 90
and if throttle is closed and if altitude is less than 350 feet, then "AUTO" relay
will energize and hold. The "UP" relay will drop out (if it was energized).
The "DOWN" relay will energize. The "AUTO" relay will remain energized and
holding until the switch is moved to the center, off, position or moved to
the down position. "Auto down" is disabled when switch is off.
Comments and criticism welcome.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=466838#466838
Attachments:
http://forums.matronics.com//files/cozy_nose_gear_185.jpg
Message 6
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Subject: | Re: M27500 Shielded Wire For Strobe |
At 01:13 PM 3/3/2017, you wrote:
>Wow... Bob and Simon I am very grateful for your
>time. I cannot contribute much back to this
>forum however on other forums where I have some
>tid bits of ignorance to expound upon I try to
>help where I can so as to "cyber pay it forward".=C2
>
>Yes it seemed odd to me to have to shield a DC
>supply wire to the power inputs of a DC unit.
>Output wires from the strobe box to the strobe
>lights on the wings could have a argument.=C2
>
>I will certainly twist the power feed wire pairs as suggested for this
box.=C2
>
>I also have two Light Speed Plasma III ignition
>units and two aircraft batteries. Since Klaus
>recommends running the POS and NEG wires
>directly from the battery terminals (through a
>reset able CB) to the units I will also twist those pairs.=C2
That's a bit of OVERKILL . . . strike that . . .
it's a LOT of overkill. Klaus and I had
had some discussions about it and he didn't
disagree with me but still seems to get some kind
of comfort/satisfaction from running wires directly
to batteries.
Failure mode effects analysis and simple probability
studies demonstrate that each ignition simply needs
its own power source with no chance of single failure
bringing down both ignition systems. A prime example
of yet another flavor of poor FMEA is illustrated
here: http://tinyurl.com/msfmldj
If I were putting Lightspeed (or any other pair
of engine support accessories) in a TC aircraft,
I think my DARs would be happy with one ignition
powered from the battery bus on its own breaker/fuse
and powering the other from the main bus . . it
too powered by its own protection. Ground the
accessories locally (metal airplane) or to the
grounding hub on the firewall (see Figure Z-15).
Twisting the power/ground pairs is of no value
in reduction of noise. If the accessory dumps
and excessive level of noise back to the bus then
shielding/twisting won't help . . . furhter, the
product would not pass DO-160 qualification
testing for installation on a TC aircraft.
>My power feeds from the associated CB to the
>radios is a very small run and there is no
>negative wire nearby to twist so I guess that is a wash.=C2
Scrap the twisting thing . . .
>I do have some other wires from DC CBs to
>switches and then to appliances such as landing
>/taxi/beacon /voltage regulators and some of
>those wires runs will be bundled next to the
>XPNDR /ADS-B /NAV/COM coaxial cables (using the
>coaxial cable Bob recommended). I suppose the
>shield on the coax will do the trick.=C2
Your filtering apples out of your sack of
oranges. Shields on coaxes have a completely
different task . . . they have nothing in
common with shielding as a noise abatement
device. Coaxes bundled with virtually
any other wires raises no concerns for
inter-system interference.
Bob . . .
Message 7
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Subject: | Re: M27500 Shielded Wire For Strobe |
Thanks Bob for the valuable information!!!
Bill Hunter
On Mar 3, 2017 16:55, "Robert L. Nuckolls, III" <
nuckolls.bob@aeroelectric.com> wrote:
> At 01:13 PM 3/3/2017, you wrote:
>
> Wow... Bob and Simon I am very grateful for your time. I cannot contribut
e
> much back to this forum however on other forums where I have some tid bit
s
> of ignorance to expound upon I try to help where I can so as to "cyber pa
y
> it forward".=C3=82
>
> Yes it seemed odd to me to have to shield a DC supply wire to the power
> inputs of a DC unit. Output wires from the strobe box to the strobe light
s
> on the wings could have a argument.=C3=82
>
> I will certainly twist the power feed wire pairs as suggested for this
> box.=C3=82
>
> I also have two Light Speed Plasma III ignition units and two aircraft
> batteries. Since Klaus recommends running the POS and NEG wires directly
> from the battery terminals (through a reset able CB) to the units I will
> also twist those pairs.=C3=82
>
>
> That's a bit of OVERKILL . . . strike that . . .
> it's a LOT of overkill. Klaus and I had
> had some discussions about it and he didn't
> disagree with me but still seems to get some kind
> of comfort/satisfaction from running wires directly
> to batteries.
>
> Failure mode effects analysis and simple probability
> studies demonstrate that each ignition simply needs
> its own power source with no chance of single failure
> bringing down both ignition systems. A prime example
> of yet another flavor of poor FMEA is illustrated
> here: http://tinyurl.com/msfmldj
>
> If I were putting Lightspeed (or any other pair
> of engine support accessories) in a TC aircraft,
> I think my DARs would be happy with one ignition
> powered from the battery bus on its own breaker/fuse
> and powering the other from the main bus . . it
> too powered by its own protection. Ground the
> accessories locally (metal airplane) or to the
> grounding hub on the firewall (see Figure Z-15).
>
> Twisting the power/ground pairs is of no value
> in reduction of noise. If the accessory dumps
> and excessive level of noise back to the bus then
> shielding/twisting won't help . . . furhter, the
> product would not pass DO-160 qualification
> testing for installation on a TC aircraft.
>
> My power feeds from the associated CB to the radios is a very small run
> and there is no negative wire nearby to twist so I guess that is a wash.
=C3=82
>
>
> Scrap the twisting thing . . .
>
>
> I do have some other wires from DC CBs to switches and then to appliances
> such as landing /taxi/beacon /voltage regulators and some of those wires
> runs will be bundled next to the XPNDR /ADS-B /NAV/COM coaxial cables
> (using the coaxial cable Bob recommended). I suppose the shield on the co
ax
> will do the trick.=C3=82
>
>
> Your filtering apples out of your sack of
> oranges. Shields on coaxes have a completely
> different task . . . they have nothing in
> common with shielding as a noise abatement
> device. Coaxes bundled with virtually
> any other wires raises no concerns for
> inter-system interference.
>
> Bob . . .
>
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