Today's Message Index:
----------------------
1. 12:03 AM - Re: Antenna length (JOHN TIPTON)
2. 06:38 AM - Re: Hall Effect rpm sensor (Robert L. Nuckolls, III)
3. 07:24 AM - Re: Antenna length (Tim Andres)
4. 07:48 AM - Re: Antenna length (Rob Henderson)
5. 10:46 AM - Re: RPM Sensor (Michael Welch)
6. 02:08 PM - Re: Antenna length (dlj04)
7. 05:18 PM - 1562A problem (Janet Amtmann)
8. 07:06 PM - Re: 1562A problem (David Lloyd)
Message 1
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Subject: | Re: Antenna length |
or any reason not to "role my own"
1) Time spent could be better utilized
2) Professional manufactured work out of the box
3) Will the 'role my own' product be readily reproducible in case of
damage to the original
John
----- Original Message -----
From: Rob Henderson
To: aeroelectric-list@matronics.com
Sent: Tuesday, June 19, 2012 9:11 PM
Subject: AeroElectric-List: Antenna length
Hi all
I would like to make a couple of antennas for my Glastar.
Does anyone know what the length is for dipole, or any reason not to
"role my own".
Transponder:
Comm:
Nav:
Marker:
Glide Slope:
UAT:
I will be using Garmin
GTX327
SL30
GMA340
Navworxs ADSB
Thanks in advance for all advice
-Rob Henderson
Message 2
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Subject: | Hall Effect rpm sensor |
At 10:32 AM 6/19/2012, you wrote:
>Bob,
>
> Thank you for replying!
>
>Here are some of the parameters:
>
>1) motor shafts are anticipated to rotate between 0-300 rpm
Okay, if you were going to display on an analog instrument,
you'd want a sensor that was watching say, 10 events per
revolution so that you were measuring 3000 evenst/min or
50 events/second. It's hard to get a fast responding display
that is also free of 'wiggles' when the measured frequency
is below 20 Hz or so.
With a digital instrument, one can measure the period of time
between pulses and then calculate rpm . . . this technique
will get you a good rpm measurement for every counted event.
>2) the tach-displays need to be remotely, and permanently mounted
>(in a console)
>(I really like that digital tach you suggested!!)
This is an automotive device that probably expects to
get a signal from the ignition system. It's scaled internally
to present shaft rpm when the engine produces 3 or 4
ignition events per revolution. The specs on this instrument
are suspect when they said, "A tach adapter may be required if
you have a multiple coil ignition system to ensure a proper signal."
It didn't mention whether the instrument had a jumper setting
to allow tailoring the installation to cars of different
engine sizes. I've built tach adapters that would convert
observed shaft RPM into a signal that would emulate an
engine . . . but that's a bit of added fuss that you
probably want to avoid if practical.
>3) the 'precise' motor rpms do not have to be "highly accurate",
>but they do need to be consistant.
>(in other words, if the shaft is actually spinning at 307 rpms, and
>the gauge says "320", that's fine, as long as
>each time it is consistantly off the same amount!)
Digital can and should be quite accurate and very
repeatable to +/- one least significant digit.
But how sensitive is your process to RPM variations
in the 1 LSD range? 320 real RPM on some tachs might
produce a 319-320-321 "wobble" in readings. In other
words, just how accurate dose the displayed speed
reading need to be. Again, having lots of events per
revolution (10-20 toothed gear to stroke your sensor).
> I did find a very nice electronics package that was close to what
> I'm looking for, but it had a couple of
>glitches. First glitch was the rpm range it measured, which was way
>too high, and the second glitch was the
>two 7 segment displays, when I would prefer an actual tachometer
>like the one you suggested.
> See:
>http://www.eio.com/p-23310-velleman-k2625-digital-tachometer.aspx
>
> Thanks for your help, Bob,
You've probably seen the response from Jim Hausch.
He's no doubt slain this dragon many times. Why
don't you guys strike up a battle plan on the List?
I'll join in if I think I've got something extra to
contribute but I'll bet Jim can handle it.
If it turns out that you do need some kind of data
conversion device, We might be able to accommodate
the requirement with custom software in the open
source, digital wig-wag project board. Our byte
herding friends here on the List could probably
get the board to sing, dance and do dishes for your
application.
Bob . . .
Message 3
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Subject: | Re: Antenna length |
Hi John
Not to be argumentative, but IMO foil dipoles are very easy to make, take pe
rhaps 30 minutes to assemble
and work quite well. Best of all they don't add drag!
The foil and ferrite beads are readily available from ACS, and the leg lengt
hs can be determined easily.
For the gps you probably should use a manufactured product as most of these a
re powered and amplified
devices. For a glass plane and antennas for VHF, I don't think there is a be
tter option.
RST sells a kit, but I keep hearing reports on an other list of the kits shi
pping months after the order.
Tim
Sent from my iPad
On Jun 20, 2012, at 12:02 AM, "JOHN TIPTON" <jmtipton@btopenworld.com> wrote
:
> or any reason not to =9Crole my own"
>
> 1) Time spent could be better utilized
> 2) Professional manufactured work out of the box
> 3) Will the 'role my own' product be readily reproducible in case of da
mage to the original
>
> John
> ----- Original Message -----
> From: Rob Henderson
> To: aeroelectric-list@matronics.com
> Sent: Tuesday, June 19, 2012 9:11 PM
> Subject: AeroElectric-List: Antenna length
>
> Hi all
> I would like to make a couple of antennas for my Glastar.
> Does anyone know what the length is for dipole, or any reason not to
=9Crole my own=9D.
>
> Transponder:
> Comm:
> Nav:
> Marker:
> Glide Slope:
> UAT:
>
> I will be using Garmin
> GTX327
> SL30
> GMA340
> Navworxs ADSB
> Thanks in advance for all advice
> -Rob Henderson
>
>
> href="http://www.matronics.com/Navigator?AeroElectric-List">http://www.m
atronics.com/Navigator?AeroElectric-List
> href="http://forums.matronics.com">http://forums.matronics.com
> href="http://www.matronics.com/contribution">http://www.matronics.com/c
>
>
==========================
=========
==========================
=========
==========================
=========
==========================
=========
>
Message 4
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Do not order from RST
I have been waiting for a kit since January it is now almost July.
They took my money though.
They do not answer email and the phone number just rings.
-Rob
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Tim
Andres
Sent: Wednesday, June 20, 2012 7:23 AM
Subject: Re: AeroElectric-List: Antenna length
Hi John
Not to be argumentative, but IMO foil dipoles are very easy to make,
take perhaps 30 minutes to assemble
and work quite well. Best of all they don't add drag!
The foil and ferrite beads are readily available from ACS, and the leg
lengths can be determined easily.
For the gps you probably should use a manufactured product as most of
these are powered and amplified
devices. For a glass plane and antennas for VHF, I don't think there is
a better option.
RST sells a kit, but I keep hearing reports on an other list of the kits
shipping months after the order.
Tim
Sent from my iPad
On Jun 20, 2012, at 12:02 AM, "JOHN TIPTON" <jmtipton@btopenworld.com>
wrote:
or any reason not to =9Crole my own"
1) Time spent could be better utilized
2) Professional manufactured work out of the box
3) Will the 'role my own' product be readily reproducible in case of
damage to the original
John
----- Original Message -----
From: Rob Henderson <mailto:robnrobinh@comcast.net>
Sent: Tuesday, June 19, 2012 9:11 PM
Subject: AeroElectric-List: Antenna length
Hi all
I would like to make a couple of antennas for my Glastar.
Does anyone know what the length is for dipole, or any reason not to
=9Crole my own=9D.
Transponder:
Comm:
Nav:
Marker:
Glide Slope:
UAT:
I will be using Garmin
GTX327
SL30
GMA340
Navworxs ADSB
Thanks in advance for all advice
-Rob Henderson
href="http://www.matronics.com/Navigator?AeroElectric-List">http://www.
matronics.com/Navigator?AeroElectric-List
href="http://forums.matronics.com">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/c
=========
st">http://www.matronics.com/Navigator?AeroElectric-List
=========
cs.com
=========
matronics.com/contribution
=========
Message 5
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Jim, Bob, list members,
Thank you for your responses. My initial request was brief, in an
attempt to pay respect to the Matronics rules, since obviously my needs
are not aviation related. They are, however, electronic in nature, and
I, for one, always enjoy every electronic post, aviation or not, because
I always enjoy learning from the best!! Since Bob suggests bringing the
subject onto the this list, I hope those that read this topic are able
to glean some electronic knowledge and, or share their skills.
So, with an understanding this topic is not aero-electric, but yet it
certainly is electronic, so it may help educate some of us electronic
novices, here goes;
My recently submitted, patent-pending invention (UNDERWATER GOLD
PROCESSOR) is essentially an underwater, remotely powered Bobcat style,
ocean floor, skidloader/material sifter. ALL functions are
hydraulically powered, and the means (pump, controls, etc) remain
onboard the (floating) dredge, and at the control of the operator.
Hydraulic lines, air lines, electric cords, etc, etc, combine in
conjunction with the suction hose, that goes down to the machine, at an
approx. depth between 10 to 30 feet. (although 100' depth may be a
consideration)
My invention is essentially a "tractor" (sort of), that clears big
boulders out of the way, scoops up tremendous amounts of sea floor dirt,
classifies the dirt to discard the rocks and unwanted gravel, and sends
the remaining gold ore concentrate up to the dredge in phenomenal
amounts. The dredge then processes this gold ore in traditional
sluicebox methods. The present method, known as 'state of the art', in
use today is a diver walking along the seafloor with a suction hose.
This diver and the dredge operator frequently pull in 1/2 oz/day. My
machine replaces this diver, and is anticipated to produce at least 20
to 50 times (or MUCH more) his daily gold tally.
Initial calculations, with my machine progressing forward at an easy,
and likely "1/2 mph", suggest processing 4 cubic yards of sea floor dirt
PER MINUTE. Since much of the coast off
of Nome has gold assayed at .01 oz AU per cu/yd, that equates close to
4/100 oz./minute ($72/min), or, on a productive day, 10 hrs X 60
minutes/hr X .04 oz/min = 24 oz AU per day. These calculations
are for the "personal" size machine. The commercial model is off the
charts! (30 cu/yds per minute {that's an ounce every three minutes).
As with many things, the bigger the machine, the better it operates.
My invention does not require a human operator controlling it
"hands-on" underwater, but rather, the dredge operator still need to be
able to monitor the various implement functions (rotating shaft's
speed)from the boat. Of all the various rotating parts, two are of
primary importance. The first one is sort of a rototiller style rock
remover, and the second function is the revolving scoops conveyor.
Although underwater video cameras are expected to assist the operator in
monitoring the machine's efficiency, through practice and experience, he
would be greatly augmented by knowing how fast the two primary
implements are turning. "Extremely precise" readings are not likely
needed. For instance, once the operator gets used to working the
machine, he may find that 215 rpm seems to work well with most seafloor
regions. So, when he sets himself up for the beginning of his daily
run, he can set the speed of that at a "proven-to-be-successful" 215
rpms, or something close to that. Obviously, rpms in the range of
200-230 are probably 'close enough' to watch the action, and he can make
adjustments as needed.
I am convinced my invention can, and will, make some people very
wealthy. There are unique features about it that I have not discussed
so far.
My intention is to either license it to a fabrication plant, or maybe
even begin making them myself, (if I could find an investor). I just
put together a website this past weekend, and is a "work-in progress".
(I don't have anything on it yet) However, I am building a 1/4 scale,
fully functioning model, too, and am about 60% finished with the model.
I will video the model in action, and post it on my website as soon as I
can. My wife just conceded she "may" actually agree to me building the
very first one, and go use it! If I were to build one, I'd need those
rpm circuits figured out, for sure.
If I were ever to fabricate them on a commercial level, the monitoring
circuits would need to be in a "plug & play" package.
Shaft rpm's would be needed for 5 separate functions. Underwater salt
environment. 20' average depth. rpm ranges around 0-
300. I'd prefer digital accuracy.
Thank to all for their tolerance to this non-aviation subject. Please
feel free to contribute any suggestions regarding the rpm circuitry.
However, if anyone is interested in further discussions regarding my
invention itself, please contact me OFF-LIST, as appropriate.
Mike Welch
On Jun 20, 2012, at 8:52 AM, Jim Hausch wrote:
> Sounds like a neat project. My last "out of the ordinary" project was
DARPA funded. It was to test the idea for an automated winch to deploy
a soldier on a parachute from an autonomous jetski. The idea is that
the jetski would pull him to altitude and then he would disconnect and
glide to shore or "wherever". I worked on the winch controls. It is
certainly more fun than the usual factory applications I work on.
>
> Your application just might beat that one out for "cool factor with
the ability to actually make some money!" :)
>
> At what depth do the sensors need to survive?
>
> It sounds like the displays are to help the operator of the tractor
know what his manipulation of the proportional valves are doing. If you
think he might ever actuate the motors to turn very slowly, we might
want to display RPM with at least one digit to the right of the decimal
point and want more "data" than one pulse per rev.
>
> Are there any other system readouts that would be of value to the
operator (pressures, levels, depths, etc)? I ask because if you get up
to more than 4 individual meters, looking at a single larger
programmable display starts to make more sense.
>
> Let me know the answer to at least the depth question and I will work
first on the simple RPM display.
>
> Jim Hausch
> Power/mation
> Cell - 414-254-1857
> Office - 262-408-6146
>
> On Jun 20, 2012 8:25 AM, "Michael Welch" <mdnanwelch7@hotmail.com>
wrote:
> Hi Jim,
>
> Thank you for your response and interest in my post regarding an rpm
meter.
> This reply is also off Matronics, mostly because my need is non-aero,
but it certainly is
> electric.
> So, unless we get sort of an invite from Bob, I think it is courtesy
to stay off-list. So, I thank you.
>
> Now, to answer your questions, but first, some background info on
why I need the rpm circuits;
> For the last 3+ months, I have been working on an invention. It is
in the field of gold prospecting,
> and very specifically, underwater offshore gold prospecting. About a
month ago, I submitted my
> completed application for a "non-provisional patent" to the US Patent
& Trademark Office (USPTO).
>
> My invention replaces the typical underwater diver (lugging an 8"
suction hose). It is essentially an
> underwater remotely operated tractor. My calculations predict between
20 to 50 times
> his productivity. (picture the comparison between a guy digging a
ditch with a shovel, and an excavator)
> At any rate, my invention relies on hydraulic motors to perform its
sundry motions. I don't have any
> detailed designs of the particular shafts, but if I knew what the rpm
circuit(s) would look like, I would
> make accommodations as necessary. In all likeliness, the shafts(s)
will be simple rotating axles,
> where an attachment (magnet?) can be mounted to give a rotational
pulse. The environment is
> underwater, (sea water).
>
> See below for additional answers adjacent to the question.
>
> Thanks for your help,
> Mike Welch
>
> On Jun 20, 2012, at 5:52 AM, Jim Hausch wrote:
>
>> Mike,
>>
>> I am a lurker on Aero-Electric. I noticed your post (and Bob's
reply) looking for some RPM meters. I work in factory automation, so
this is right up our alley. I am sending this from my work email so if
we start a conversation I have the record "where i need it".
>>
>> Bob (CC'd on this message),
>>
>> If you would prefer I recap this on the Matronics list, please let me
know.
>>
>> Mike,
>>
>> What is on the shaft that the sensor will sense? Is there a key,
flat, or other feature we can sense with a simple inductive prox? If
you have a drawing or picture of the shaft, please send it along.
(assume a simple 1 1/2" dia., full-length woodruff keyed, rotating steel
shaft, in an underwater environment)
>> How many shafts need to be measured simultaneously? (two
separate,independent circuits, at least, with two displays. However,
depending on the design, I could use as many as 6)
>> How large would you like the display to be? (if gauges are
individual, 2" or so, each. If multiple displays per single screen,
maybe 1/4" to 3/8" high numbers)
>> What sort of environment does the system need to live in? (sensors
live in salt water, displays live in dry, above water, console)
>> What is the available power (115 from a wall outlet, or is there an
existing panel with lower voltage AC or even a 24Vdc supply in it)?
(the dredge (support boat) will have any form of necessary power. 115
ac will be available, BUT, due to the water hazards, I would greatly
prefer to stay with something no more dangerous than 24Vdc. 12Vdc would
be my most preferred, but 24Vdc would be fine if a circuit operated
better with it)
>> Let me know and I can give you a proposal.
>>
>> Regards,
>> Jim Hausch
>> Power/mation
>> Cell - 414-254-1857
>> Office - 262-408-6146
>>
>> Interesting Information and Random Updates
>>
>
Message 6
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Subject: | Re: Antenna length |
Rob Henderson wrote:
>> Hi all
>>
>> I would like to make a couple of antennas for my Glastar.
>>
>> Does anyone know what the length is for dipole, or any reason not to
>> "role my own".
>>
>> Transponder:
>>
>> Comm:
>>
>> Nav:
>>
>> Marker:
>>
>> Glide Slope:
>>
>> UAT:
You've seen in other replies the lengths you should plan for, and length
is of course important. Other parameters are at least as important,
though. Everything metal in your airplane (including the cable that
leads to your dipole) is a part of your antenna, and will influence its
frequency range and directivity, whether you want it to be or not. The
resin you use in your composite structure can also influence the
electrical length of your antenna elements.
The only reason not to roll your own is that it takes a while to learn
what you need, build and test your results. Using wide (1" for VHF, 1/2"
for txp/DME/UAT) foil tape, genuine current mil spec or land mobile
grade coaxial cable and connectors, and the factory-specified crimp tool
for the connectors will make it much easier and more reliable. Surplus
lengths of mil spec or LMR foam coax cable with the connectors already
installed with proper factory gear may be your best bet (but avoid
adapters and splices!) You can lay out your antennas on a thin piece of
glass cloth, tape it in place on your airplane for ground tests, and
then bond it in place later.
Transponder is particularly tricky because of the frequency and power
level, although not so bad with your Garmin GTX-327 as with older types
that have a cavity tube (which can be detuned by off-frequency
antennas). You probably don't have a way to check SWR at transponder
frequencies. Besides reduction in range, high SWR could damage the
output of the transponder. I would hope but don't know that the Garmin
is protected against that. You should confirm that it can operate into a
high SWR load without damage (it should shut down rather than smoking
the final power amp stage.)
Comm is probably the most critical, particularly now that you need to
cover the whole 118-137 MHz band. You can use distant ATIS/AWOS stations
as test signal sources, and compare where you can receive given stations
with results from a known good installation. A vertical or sloping
dipole is good if you have the space (about 47") but you may find that a
quarter-wave monopole and counterpoise ("ground plane") might be easier
to do and easier to match. Folding dipoles and monopoles is also
possible but requires a lot of extra analysis and test. Fortunately,
preserving true vertical polarization isn't that important.
A wing-mounted vee dipole is good (assuming it's far enough away from
other conductors) but many of the designs I've seen are nearly straight
-- which means poor reception off the ends. An asymmetrical
installation, like one of the shunt-fed wingtip antennas, might be fine
for VOR but can give different results if you intercept a localizer from
the left or from the right. GS and marker are much less critical.
A wideband transponder/DME antenna will work fine for UAT which is in
the DME band at 978 MHz. You could put it at the tip of the tail for
good coverage on the ground, for instance, but this means a lot of loss
in the cable (unless you put the UAT in the tailcone). Likewise the
transponder antenna is best placed on the belly, but you need to think
about reflections from the gear legs. This is one area where you might
choose a factory type - the "all metal" NI-50 antennas are particularly
good, rugged, low drag and often found on auction sites (they may have
an uncommon "C" connector if they come from airline surplus, but these
are available and very low loss.)
There are lots of military designs that can teach a lot about antennas.
Sometimes you see slow airplanes and helicopters that look like a
combination of a porcupine and a circus act, but others have everything
embedded using patch, slot and notch topologies. I've been a little
surprised that no one has really embraced some of these designs for
homebuilts, although they have been used in some airliners over the years.
Message 7
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I have several trusty Schumacher 1562A maintainers, but one of them
suddenly stopped maintaining and stayed on charge (yellow light). I
fortunately caught it in time to keep the AGM battery from being damaged.
I tried it on another AGM and same problem. Schumacher says that the unit
can not be repaired since it is a sealed unit. Doesn't appear sealed to
me. I took it apart and the transformer and PCB are plainly visible. Can
anyone advise me as to how to check what the problem with the PCB might be?
I'm not an electronics type but an ME, so I can follow directions. If I
can't fix it I'll buy a new one, but my inclination is to rather fix than
buy.
Jurgen Amtmann
Message 8
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Subject: | Re: 1562A problem |
Jurgen,
Since you opened up the box, there is probably a small pot that can be
adjusted. That maybe bad or just sitting on a bad spot on the
potentiometer. Turn the pot wiper a small amount and clip it back to a
battery and see if it will regulate and go to a float mode by watching
with your voltmeter.
If it will not regulate then the solid state regulator chip has probably
gone bad.
Most of the "low cost" maintainers like to be powered up in a set
sequence.
Connect clips to the battery first, then, plug into wall power. And,
reverse that to shut down. AC power off first, then unclip from the
battery. Not sure how many cycles they can take if not done in that
order....
D
-------------------------------------------------------------------------
-------
----- Original Message -----
From: Janet Amtmann
To: aeroelectric-list@matronics.com
Sent: Wednesday, June 20, 2012 5:16 PM
Subject: AeroElectric-List: 1562A problem
I have several trusty Schumacher 1562A maintainers, but one of them
suddenly stopped maintaining and stayed on charge (yellow light). I
fortunately caught it in time to keep the AGM battery from being
damaged. I tried it on another AGM and same problem. Schumacher says
that the unit can not be repaired since it is a sealed unit. Doesn't
appear sealed to me. I took it apart and the transformer and PCB are
plainly visible. Can anyone advise me as to how to check what the
problem with the PCB might be? I'm not an electronics type but an ME,
so I can follow directions. If I can't fix it I'll buy a new one, but
my inclination is to rather fix than buy.
Jurgen Amtmann
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