Today's Message Index:
----------------------
1. 03:06 AM - Re: Source for Bakelite - 1/32" thick (Alfio)
2. 08:31 AM - Re: Source for Bakelite - 1/32" thick (racerjerry)
3. 09:04 AM - Re: Re: Source for Bakelite - 1/32" thick (Robert L. Nuckolls, III)
4. 01:51 PM - Re: Wingtip VOR antenna . . . a clearer picture (Robert L. Nuckolls, III)
5. 04:25 PM - Re: Re: Wingtip VOR antenna . . . a clearer picture (Don)
6. 04:47 PM - Re: Re: Wingtip VOR antenna . . . a clearer picture (Jeff Luckey)
7. 06:43 PM - Re: Re: Wingtip VOR antenna . . . a clearer picture (Robert L. Nuckolls, III)
8. 06:43 PM - Re: Re: Wingtip VOR antenna . . . a clearer picture (Robert L. Nuckolls, III)
9. 07:51 PM - Re: Re: Wingtip VOR antenna . . . a clearer picture (Jeff Luckey)
10. 07:54 PM - Should I Buy an SWR Meter? (Jeff Luckey)
11. 08:26 PM - Re: HID lighting observations (Dave Saylor)
12. 10:04 PM - Re: Re: Wingtip VOR antenna . . . a clearer picture (Robert L. Nuckolls, III)
13. 11:48 PM - Re: HID lighting observations (Thomas Johnson)
Message 1
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Subject: | Re: Source for Bakelite - 1/32" thick |
nuckolls.bob(at)aeroelect wrote:
> At 11:09 AM 3/27/2012, you wrote:
>
> Did a little Autocad layout and found that the top
> capacitor plate doesn't come all the way to the end
> of the capacitor di-electric. Given that it's
> a 60-60-60 triangle with an inside dim of 5.00
> inches, the details come out something like this:
>
>
> http://tinyurl.com/7wol3jx (http://tinyurl.com/7wol3jx)
>
> Bob . . .
Just what I was looking for. Thanks.
Alfio
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=369456#369456
Message 2
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Subject: | Re: Source for Bakelite - 1/32" thick |
Be careful when substituting non-reinforced plastic material for Micarta sheet.
Often, you will need a phenolic laminate material with resin impregnated layers
of linen cloth to provide support and to preserve electrical spacings at elevated
temperatures. Many non-reinforced plastics will begin to flow when heated.
Impregnated cloth or paper will maintain some electrical spacing even when
charred.
Aircraft Spruce still sells Grade L (linen base) phenolic sheet 1/16 and thicker,
which is the generic equivalent of Micarta.
--------
Jerry King
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=369466#369466
Message 3
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Subject: | Re: Source for Bakelite - 1/32" thick |
At 10:29 AM 3/28/2012, you wrote:
>
>Be careful when substituting non-reinforced
>plastic material for Micarta sheet. Often, you
>will need a phenolic laminate material with
>resin impregnated layers of linen cloth to
>provide support and to preserve electrical
>spacings at elevated temperatures. Many
>non-reinforced plastics will begin to flow when
>heated. Impregnated cloth or paper will
>maintain some electrical spacing even when charred.
>
>Aircraft Spruce still sells Grade L (linen
>base) phenolic sheet 1/16 and thicker, which
>is the generic equivalent of Micarta.
Good thoughts. At least this case doesn't raise
critical questions as to structural integrity. The
parts being joined are exceedingly light.
The substitution problem here is two-fold. Structural
as you've correctly deduced PLUS electrical. The insulating
material is the dielectric for a high frequency capacitor
that is expected to TUNE out some reactive components of
the gamma-match elements.
A List member is sending me a store-bought antenna.
I'll mount it on a ground plane and get some SWR data.
Then I'll measure the VALUE of the as-purchased capacitor.
Then we'll have a basis for evaluating the electrical
qualities of any proposed substitution.
I'm thinking that we can fabricate the struts, insulator
and capacitor from a single piece of double-sided etched
circuit board material. I have lots of the material to
play with and can pretty easily test it against the store
bought design for optimal dimensions.
In fact, I'm considering a 'mod' to the design that
uses a variable capacitor soldered down to the ECB
material . . . which must be adjusted but it's pretty
easy to do with the ship's comm transmitter or a hand
held and an SWR meter.
Bob . . .
Message 4
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Subject: | Re: Wingtip VOR antenna . . . a clearer picture |
Thanks to List member van Saten, we've got some
better details for a DIY wingtip VOR antenna. See:
http://tinyurl.com/6v5gvhx
It seems that the sketch I was working from years ago
was either not up to date or in error.
The insulator turns out to be either glass or cloth
filled phenolic, 0.062 inches thick. The measured
value of an off-the-shelf gamma-match capacitor is
34 pf @ 1 KHz.
I think the data above will get the builder closer to
a workable example of this particular antenna.
Thanks Don! Your antenna will be back in the mail today.
Bob . . .
Message 5
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Subject: | Re: Wingtip VOR antenna . . . a clearer picture |
Bob,
Did you install the new cap or jhust test it by itself?
-----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, March 28, 2012 1:48 PM
Subject: AeroElectric-List: Re: Wingtip VOR antenna . . . a clearer picture
--> <nuckolls.bob@aeroelectric.com>
Thanks to List member van Saten, we've got some better details for a DIY
wingtip VOR antenna. See:
http://tinyurl.com/6v5gvhx
It seems that the sketch I was working from years ago was either not up to
date or in error.
The insulator turns out to be either glass or cloth filled phenolic, 0.062
inches thick. The measured value of an off-the-shelf gamma-match capacitor
is
34 pf @ 1 KHz.
I think the data above will get the builder closer to a workable example of
this particular antenna.
Thanks Don! Your antenna will be back in the mail today.
Bob . . .
Message 6
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Subject: | Re: Wingtip VOR antenna . . . a clearer picture |
Bob,
Thanks for this drawing. It gives me a general idea of what this thing is -
I could almost build one from it... A few more dimensions would be very
helpful. (or else I'll have to get out my trig calculator)
My wish list:
1. Explicit dimensions for length of each piece
2. A label for each piece. For us antenna ignoramuses (or is that
ignorami?) I cannot differentiate between the "antenna" and "ground strut".
3. Call-out fastenings and their positions. Are they critical? (e.g. can I
substitute a #4 machine-screw & nut instead of a 3/32 dia. aluminum rivet or
a #6 screw or a #8, etc?)
4. Some very explicit instructions about how to connect the feed line:
a. how to prepare the shield (I'm assuming a coax feed line)
b. type of wire terminals (or is it soldered?)
c. or can a coax connecter be installed on the antenna
5. How is the structure mounted in the airplane?
How did you measure the capacitance? As someone who knows nada about RF, a
spec like X pf at Y freq fascinates me..
Thx,
Jeff Luckey
-----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, March 28, 2012 12:48
Subject: AeroElectric-List: Re: Wingtip VOR antenna . . . a clearer picture
<nuckolls.bob@aeroelectric.com>
Thanks to List member van Saten, we've got some
better details for a DIY wingtip VOR antenna. See:
http://tinyurl.com/6v5gvhx
It seems that the sketch I was working from years ago
was either not up to date or in error.
The insulator turns out to be either glass or cloth
filled phenolic, 0.062 inches thick. The measured
value of an off-the-shelf gamma-match capacitor is
34 pf @ 1 KHz.
I think the data above will get the builder closer to
a workable example of this particular antenna.
Thanks Don! Your antenna will be back in the mail today.
Bob . . .
Message 7
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Subject: | Re: Wingtip VOR antenna . . . a clearer picture |
At 07:45 PM 3/28/2012, you wrote:
Bob,
Thanks for this drawing. It gives me a general idea of what this thing is -
I could almost build one from it... A few more dimensions would be very
helpful. (or else I'll have to get out my trig calculator)
Or lay it out on a sheet of paper. Agreed, my dimensioning
would get me a strong reprimand from the checkers at the
last place I did any drawings for production release. That
would have been Electro-Mech about 30 years ago!
My wish list:
1. Explicit dimensions for length of each piece
They're pretty much there . . .
2. A label for each piece. For us antenna ignoramuses (or is that
ignorami?) I cannot differentiate between the "antenna" and "ground strut".
Do some research on how this antenna is mounted to the
the airplane. The ground strut attaches to the tip rib
of an all metal airplane.
3. Call-out fastenings and their positions. Are they critical? (e.g. can I
substitute a #4 machine-screw & nut instead of a 3/32 dia. aluminum rivet or
a #6 screw or a #8, etc?)
4. Some very explicit instructions about how to connect the feed line:
a. how to prepare the shield (I'm assuming a coax feed line)
b. type of wire terminals (or is it soldered?)
c. or can a coax connecter be installed on the antenna
5. How is the structure mounted in the airplane?
I hesitate to do highly detailed instructions on Bob
Archer's product. The amount of information I do offer
is intended as a guide for exploration. The first principal
of experimental aircraft is education. If I were to craft
such a product, it would indeed feature a captive coax
connector. The 'sketches' I offered are intended to get
you into the ball-park - not to replicate Bob's product.
How did you measure the capacitance? As someone who knows nada about RF, a
spec like X pf at Y freq fascinates me..
I have a LRC meter that displays inductance, resistance
and capacitance on a digital display. Really useful.
http://tinyurl.com/8ygt4mq
If that meter had not been at hand, I would have wound
a small coil of wire, hooked it across the unknown capacitance,
taken a resonance reading, added some known capacitance and
taken another reading. You can do this with a 'grid dip' meter.
The one I have is about 50 years old
http://tinyurl.com/6s875rp
but probably the best one ever made. It's good to 1%
of reading or better.
Suggest you get a sheet of paper and make
a full scale drawing of the finished assembly and the
component pieces. Strike up some conversation with
others here on the List about the various questions
of techniques you have cited. I think the dimensions
given will bound your options.
You're going to become a wingtip VOR antenna expert . . .
or at least a guy who has "been there, done that." I
think there's enough data there to get you off to a good,
low risk start.
Bob . . .
Message 8
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Subject: | Re: Wingtip VOR antenna . . . a clearer picture |
At 06:23 PM 3/28/2012, you wrote:
>
>Bob,
>Did you install the new cap or jhust test it by itself?
No, just measured it free and took some dimensions. Found
that the .31" and 5.0" dimensions in my earlier sketches
were in error.
Bob . . .
Message 9
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Subject: | Re: Wingtip VOR antenna . . . a clearer picture |
I apparently mis-understood the purpose of your posting. I thought it was
to provide complete instructions & how-to. (and I thought it was a little
odd that there were omissions, since your documentation is usually
hyper-meticulous)
>From what you've provided, one can certainly deduce the remaining
dimensions.
However I still need help on nomenclature. The ground strut is the
horizontal 1.5 in wide piece shown at the bottom of your drawing. Is that
correct?
I was wondering about how Mr. Archer played into this situation. I, too,
have some level of discomfort simply copying his design, and I believe that
this antenna is available for < $100. At that price, it hardly pays to
do-it-yourself except as an educational exercise.
Also, I'm interested in connecting a coax connector directly to the antenna.
Do you feel comfortable elaborating on that topic?
-Jeff
-----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, March 28, 2012 17:41
Subject: RE: AeroElectric-List: Re: Wingtip VOR antenna . . . a clearer
picture
<nuckolls.bob@aeroelectric.com>
At 07:45 PM 3/28/2012, you wrote:
Bob,
Thanks for this drawing. It gives me a general idea of what this thing is -
I could almost build one from it... A few more dimensions would be very
helpful. (or else I'll have to get out my trig calculator)
Or lay it out on a sheet of paper. Agreed, my dimensioning
would get me a strong reprimand from the checkers at the
last place I did any drawings for production release. That
would have been Electro-Mech about 30 years ago!
My wish list:
1. Explicit dimensions for length of each piece
They're pretty much there . . .
2. A label for each piece. For us antenna ignoramuses (or is that
ignorami?) I cannot differentiate between the "antenna" and "ground strut".
Do some research on how this antenna is mounted to the
the airplane. The ground strut attaches to the tip rib
of an all metal airplane.
3. Call-out fastenings and their positions. Are they critical? (e.g. can I
substitute a #4 machine-screw & nut instead of a 3/32 dia. aluminum rivet or
a #6 screw or a #8, etc?)
4. Some very explicit instructions about how to connect the feed line:
a. how to prepare the shield (I'm assuming a coax feed line)
b. type of wire terminals (or is it soldered?)
c. or can a coax connecter be installed on the antenna
5. How is the structure mounted in the airplane?
I hesitate to do highly detailed instructions on Bob
Archer's product. The amount of information I do offer
is intended as a guide for exploration. The first principal
of experimental aircraft is education. If I were to craft
such a product, it would indeed feature a captive coax
connector. The 'sketches' I offered are intended to get
you into the ball-park - not to replicate Bob's product.
How did you measure the capacitance? As someone who knows nada about RF, a
spec like X pf at Y freq fascinates me..
I have a LRC meter that displays inductance, resistance
and capacitance on a digital display. Really useful.
http://tinyurl.com/8ygt4mq
If that meter had not been at hand, I would have wound
a small coil of wire, hooked it across the unknown capacitance,
taken a resonance reading, added some known capacitance and
taken another reading. You can do this with a 'grid dip' meter.
The one I have is about 50 years old
http://tinyurl.com/6s875rp
but probably the best one ever made. It's good to 1%
of reading or better.
Suggest you get a sheet of paper and make
a full scale drawing of the finished assembly and the
component pieces. Strike up some conversation with
others here on the List about the various questions
of techniques you have cited. I think the dimensions
given will bound your options.
You're going to become a wingtip VOR antenna expert . . .
or at least a guy who has "been there, done that." I
think there's enough data there to get you off to a good,
low risk start.
Bob . . .
Message 10
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Subject: | Should I Buy an SWR Meter? |
Bob,
I'm building an RV7A and I'm into electronics. Should I buy an SWR meter?
I know it can help me optimize the antenna systems for my com transmitters
and I enjoy geeking-out on things like this.
Can an SWR meter help w/ the setup of VOR receivers as well. Can it help me
w/ the installation of the Bob Archer antenna for VOR? (I thought that SWR
was used primarily for measurements w/ transmitters).
Is there a "Big Dummies Guide to Antenna Theory" book available? I'd like
to squelch some of my ignorance in this area.
(so many questions, so little time.)
Thanks,
Jeff Luckey
Direct Connection Systems
www.DCSIT.com
949-645-8832
Message 11
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Subject: | Re: HID lighting observations |
Well, to date I've sent in a G530 for a screen failure, AFS EFIS for a
power supply failure (pretty dramatic), and 3 Garmin 696s, though to
be fair, one was an out-of-the-box failure so not possibly due to
transients. The 696s were for a bad screen and failure to boot.
Since I had to pay for the 530 repair anyway, I opened up the box to
peek inside. There was a burnt piece of something laying in the
bottom of the chassis. Not good. I let the professionals deal with
that one.
So I haven't had the best of luck with the "delicate" avionics. I do
have suppression diodes on all the contactors, and after the EFIS
failure I double checked each one for function and installation.
Everything was wired correctly.
--Dave Saylor
On Tue, Mar 27, 2012 at 9:13 PM, Robert L. Nuckolls, III
<nuckolls.bob@aeroelectric.com> wrote:
> <nuckolls.bob@aeroelectric.com>
>
> I'm still waiting to get into the lab to do some
> quantitative testing on some HID light kits. In
> the mean time, I've installed a pair on my Kia
> mini-van. I've observed the following:
>
> The lights generate noticeable but not overwhelming
> noise in the AM broadcast band during the warm up
> phase. About 30 seconds. Don't hear it after the
> lamps are warmed up.
>
> The kits I have generate a strong transient of some
> variety onto the bus when first turned on. If I have
> the cruise control engaged at the time, it drops off
> line. I have to shut the engine off completely to
> get the cruise control to reset and wake up.
>
> This sort of event isn't even watched for under DO-160
> explorations. I'll have to set up on the bench to capture
> and quantify this characteristic.
>
> But in the mean time, be aware that a turn-on transient
> MIGHT manifest in erratic behavior of some micro-processor
> based electro-whizzies in your airplane. If any such events
> are identified and repeatable, I'd like to know about them.
>
>
> Bob . . .
>
>
Message 12
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Subject: | Re: Wingtip VOR antenna . . . a clearer picture |
At 10:45 PM 3/28/2012, you wrote:
I apparently mis-understood the purpose of your posting. I thought it was
to provide complete instructions & how-to. (and I thought it was a little
odd that there were omissions, since your documentation is usually
hyper-meticulous)
>From what you've provided, one can certainly deduce the remaining
dimensions.
However I still need help on nomenclature. The ground strut is the
horizontal 1.5 in wide piece shown at the bottom of your drawing. Is that
correct?
Yes. Your position light wires route up the foreward blade
of the antenna and then aft to the light fixture location.
http://tinyurl.com/7kmfery
I was wondering about how Mr. Archer played into this situation. I, too,
have some level of discomfort simply copying his design, and I believe that
this antenna is available for < $100. At that price, it hardly pays to
do-it-yourself except as an educational exercise.
You got it! If you were going to build and sell
these, I suspect he might be miffed. If you were
to design and sell a better one, that's the nature
of free market competition. But if you can make this
a learning experience, I'm sure he's good with
that.
Also, I'm interested in connecting a coax connector directly to the antenna.
Do you feel comfortable elaborating on that topic?
http://tinyurl.com/7k8nryk
http://tinyurl.com/73jowsp
Bob . . .
Message 13
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Subject: | re: HID lighting observations |
> But in the mean time, be aware that a turn-on transient
> MIGHT manifest in erratic behavior of some micro-processor
> based electro-whizzies in your airplane. If any such events
> are identified and repeatable, I'd like to know about them.
When I upgraded from halogen to HID lights several years ago I had a
problem with this. My own design PIC based wig-wag controller no longer
worked at all. I found that the HID lights had a huge inrush current
each time they switched on. I tried a few fixes and got the best
results by running the HID power and ground wires together through a
1/2=9D dia X 1=9D long ferrite core. Using two in series
worked even better.
The first time I tested the ferrites I used a split half type because it
is easier to pop on and off in different locations. While I was
watching the scope I noticed a new, fairly loud clicking sound coming
from the HID controller area. It turned out to be the split ferrite
half's snapping together each time power came on. That is some serious
energy transfer!
Tom Johnson
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