Today's Message Index:
----------------------
1. 01:02 AM - Re: Radio noise (jerb)
2. 03:27 AM - Re: Next generation connectors (James Kilford)
3. 10:43 AM - Re: Headphone impedance (Robert L. Nuckolls, III)
4. 10:51 AM - 9*Nice day! (rsipp@earthlink.net)
5. 11:06 AM - Re: Headphone impedance (Ron Quillin)
6. 02:02 PM - Re: Headphone impedance (Peter Pengilly)
7. 02:51 PM - Re: Radio noise (Noel Loveys)
8. 03:17 PM - Re: Headphone impedance (Peter Pengilly)
9. 05:02 PM - Re: Headphone impedance (Robert L. Nuckolls, III)
10. 05:19 PM - Re: Headphone impedance (Robert L. Nuckolls, III)
11. 05:52 PM - Remote Power control for Aircraft PreHeater (Tim Olson)
12. 11:10 PM - PC board for avionics ground bus (Buck Wyndham)
Message 1
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Whoa - don't think the capacitor you reference should be installed in
series, it should be from the regulator +12V DC output terminal to
DC ground. Jump in if I have this wrong!
jerb
At 10:47 AM 11/29/2010, you wrote:
>I know this has been discussed before but like to ask anyway. I
>installed an old RST 360 com radio in my 701 panel and when I start
>the "Rotax" it is very noisy. Seems to be a whine don't know whether
>or not this is alternator or ignition. Saw a wiring diagram for
>another radio which stated that you must install a 22,000uf
>capacitor in series on the 12v feed when used with the Rotax engine
>installation. Will this cure the problem? Your valued thoughts please.
>
>Phil Smith
>CH 701 - Flying
>Buhl, ID
>
Message 2
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Subject: | Re: Next generation connectors |
I've used the Mate'n'lock connectors on my project quite a bit recently,
mainly because I've found it difficult to buy a small number of the
relatively expensive PIDG connectors here. Anyway, I'm very pleased with
the Mate'n'locks. They're nice and small, come in a variety of different
cable sizes, but all fit into the same wide range of shells. I've used them
to make little pluggable modules, such as internal light, map lights, tail
light, annunciator lights, etc.
Also, I've used them without a shell, as Bob has suggested for D-sub
connector pins, i.e. using the two pins and covering with heatshrink. Makes
for a compact installation, with great load-carrying capability too.
The only thing that worried me a bit was the rated 50 mating operations.
But then again I thought that I'm unlikely to EVER undo many of these
connections, and almost certainly not 50 times...
FWIW.
James
On 2 December 2010 07:27, Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> nuckolls.bob@aeroelectric.com>
>
>
>> Comments/Questions: What is your opinion of sealed connectors verses
>> standard Molex? I work in the automotive industry (Honda)and these
>> connectors seem to be much more durable and less subject to vibration and
>> corrosion. I am building The RV-8 and Would like your thoughts.
>>
>
> The Amp Mate-n-Lock nylon connectors were first
> integrated onto single-engine Cessna models about
> 1968. My relatively short tenure in the electronics
> and aviation arts suggested that airplanes were
> somehow worthy of technologies having extra-ordinary
> quality and robustness. I was understandably
> skeptical of the cheap, white plastic connectors.
>
> This was decades before I came to understand failure
> tolerant design. I was also relatively ignorant of the
> causes/effects in the history of aviation failures.
>
> 40 years later we observe that the Mate-n-Lock
> connector has probably exceeded anyone's expectations.
> Of course any connector is located such that there
> is risk for drip or splash gives us pause to consider
> special circumstances. But for the most part, the
> the perceived quality or robustness of any given
> connector has little influence on risks and only
> a small influence on cost of ownership.
>
> Some of the modern automotive under-the-hood connectors
> for are pretty impressive. I wouldn't discourage
> anyone from considering them if they have access to
> tools and a source of products.
>
>
> Bob . . .
>
>
Message 3
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Subject: | Re: Headphone impedance |
At 01:43 AM 12/2/2010, you wrote:
>Some worthy observations you've made Bob.
>
>I did some digging, and have attached an IM for the unit.
>Of interest in section "C" and "D" on pdf page 21:
>
>C. Speaker connection
>A 4 to 8 Ohm speaker can be connected to audio output P1- 1AF-asym.
>CAUTION : The magnetic field of a speaker influences the magnetic compass.
>When choosing the mounting point, a minimum distance of 1.3 m
>must be maintained between the speaker and the magnetic compass.
Yeah . . . those recommendations were written
based on magnetic interference studies done
many moons ago when it was common practice
to mount a speaker in the cabin overhead.
Believe me, those were CHEAP speakers and
not terribly well shielded magnetically.
Further, there was no way you could get 1.3M
separation from the whisky compass . . . but
that's another problem.
>D. Headphone connection
>Up to two headphones with an impedance of 600 Ohm can be connected to
>the audio output P1 - 2,3 AF-HI/LO.
It may well be that the speaker/headset configuration
Peter is proposing won't drive from the headset
output of the radio. In this case, some amplification
is called for.
I've been using a number of pre-packaged
amplifiers off ebay . . . very reasonably
priced. Here's an example that can be
had for $6 postage paid.
http://tinyurl.com/3a6oy7x
It needs to be boxed and power conditioned
for attaching to a DC bus . . . and probably
some gain setting resistors . . . but
a quick and dirty way to get substantial
boost to a stereo headset using low
impedance "speakers".
Thanks for the manual. I've added it to my
manufacturer's data library.
Bob . . .
Message 4
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ft/
Hi friend! How are you doing now? I have a friend working in a Korean company,
they have a variety of good deals, all their things are at very nice prices, their
web is zxoor.com, and you can go to their web to have a look, thanks! Best
Regards
y
Message 5
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Subject: | Re: Headphone impedance |
At 10:39 12/2/2010, you wrote:
> Thanks for the manual. I've added it to my
> manufacturer's data library.
>
> Bob . . .
Always glad to add to the community library!
tnx
Ron
Message 6
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Subject: | Re: Headphone impedance |
Thanks for all of the input!
We've had 6" of snow over the last couple of days, so getting into the
shop is not so easy - measuring the resistance of the speakers will have
to wait for a few days. They are 30mm in diameter and 8mm thick, but
don't have any kind of identifying marks on them.
I would like to use the standard headphone output from the radio as its
already wired in - and I didn't even wire up the speaker pin from the
radio, that would also make the set up transferable to other aircraft.
It also occurred to me that the standard radio will drive at least 2
headsets in parallel - so a combined impedance of 300 ohms - but Ron got
there first!
To summarize what has been said,
- Its likely that an aviation radio headset output would overdrive these
speakers (resulting in poor volume control and possibly poor quality
output), and may suffer some damage to the radio audio amplifier (unlikely).
- To use these speakers/phones I will probably need an audio isolation
amplifier (made as described in Bob's note)
- Alternatively an amp from ebay may suffice ( for $6 seems a no brainer
:-) ) - but may require some power conditioning (interesting that specs
say 4.5v, but legend on board says 12v), and also some gain setting
resistors [how do I calculate the value?]
- To use the electret mic I will have to build a circuit per Bob's sketch.
I think there are are potentially 3 ways ahead.
1. Buy amp above and start making mic circuit (perhaps gives the ability
to add an ipod input in the future)
2. Cannibalise an old headset (at least all the components should match)
3. Use the Halo headset for the time being and just figure out sticking
the ear plugs in my ears with the helmet around my neck ...
Thanks for your help, Peter
PS I also found these to provide some eye protection
http://www.davida.co.uk/type.php?id=Visor_D4Vi9A
On 02/12/2010 18:39, Robert L. Nuckolls, III wrote:
> At 01:43 AM 12/2/2010, you wrote:
>> Some worthy observations you've made Bob.
>>
>> I did some digging, and have attached an IM for the unit.
>> Of interest in section "C" and "D" on pdf page 21:
>>
>> C. Speaker connection
>> A 4 to 8 Ohm speaker can be connected to audio output P1- 1AF-asym.
>> CAUTION : The magnetic field of a speaker influences the magnetic
>> compass.
>> When choosing the mounting point, a minimum distance of 1.3 m
>> must be maintained between the speaker and the magnetic compass.
>
> Yeah . . . those recommendations were written
> based on magnetic interference studies done
> many moons ago when it was common practice
> to mount a speaker in the cabin overhead.
> Believe me, those were CHEAP speakers and
> not terribly well shielded magnetically.
> Further, there was no way you could get 1.3M
> separation from the whisky compass . . . but
> that's another problem.
>
>> D. Headphone connection
>> Up to two headphones with an impedance of 600 Ohm can be connected to
>> the audio output P1 - 2,3 AF-HI/LO.
>
> It may well be that the speaker/headset configuration
> Peter is proposing won't drive from the headset
> output of the radio. In this case, some amplification
> is called for.
>
> I've been using a number of pre-packaged
> amplifiers off ebay . . . very reasonably
> priced. Here's an example that can be
> had for $6 postage paid.
>
> *http://tinyurl.com/3a6oy7x*
>
> It needs to be boxed and power conditioned
> for attaching to a DC bus . . . and probably
> some gain setting resistors . . . but
> a quick and dirty way to get substantial
> boost to a stereo headset using low
> impedance "speakers".
>
> Thanks for the manual. I've added it to my
> manufacturer's data library.
>
> Bob . . .
>
>
> *
>
> *
Message 7
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Exactly!
Noel
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of jerb
Sent: December 2, 2010 5:28 AM
Subject: Re: AeroElectric-List: Radio noise
Whoa - don't think the capacitor you reference should be installed in
series, it should be from the regulator +12V DC output terminal to DC
ground. Jump in if I have this wrong!
jerb
At 10:47 AM 11/29/2010, you wrote:
I know this has been discussed before but like to ask anyway. I installed
an old RST 360 com radio in my 701 panel and when I start the "Rotax" it is
very noisy. Seems to be a whine don't know whether or not this is alternator
or ignition. Saw a wiring diagram for another radio which stated that you
must install a 22,000uf capacitor in series on the 12v feed when used with
the Rotax engine installation. Will this cure the problem? Your valued
thoughts please.
Phil Smith
CH 701 - Flying
Buhl, ID
Message 8
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Subject: | Re: Headphone impedance |
Also found user's guide for the ebay amp
http://www.sure-electronics.net/download/AA-AB3213X_Ver1.0_EN.pdf
catalogue here
http://www.sureelectronics.net/Amplifier.pdf
Peter
On 02/12/2010 21:58, Peter Pengilly wrote:
> Thanks for all of the input!
> We've had 6" of snow over the last couple of days, so getting into the
> shop is not so easy - measuring the resistance of the speakers will
> have to wait for a few days. They are 30mm in diameter and 8mm thick,
> but don't have any kind of identifying marks on them.
> I would like to use the standard headphone output from the radio as
> its already wired in - and I didn't even wire up the speaker pin from
> the radio, that would also make the set up transferable to other
> aircraft. It also occurred to me that the standard radio will drive at
> least 2 headsets in parallel - so a combined impedance of 300 ohms -
> but Ron got there first!
>
> To summarize what has been said,
> - Its likely that an aviation radio headset output would overdrive
> these speakers (resulting in poor volume control and possibly poor
> quality output), and may suffer some damage to the radio audio
> amplifier (unlikely).
> - To use these speakers/phones I will probably need an audio isolation
> amplifier (made as described in Bob's note)
> - Alternatively an amp from ebay may suffice ( for $6 seems a no
> brainer :-) ) - but may require some power conditioning (interesting
> that specs say 4.5v, but legend on board says 12v), and also some gain
> setting resistors [how do I calculate the value?]
> - To use the electret mic I will have to build a circuit per Bob's sketch.
>
> I think there are are potentially 3 ways ahead.
> 1. Buy amp above and start making mic circuit (perhaps gives the
> ability to add an ipod input in the future)
> 2. Cannibalise an old headset (at least all the components should match)
> 3. Use the Halo headset for the time being and just figure out
> sticking the ear plugs in my ears with the helmet around my neck ...
>
> Thanks for your help, Peter
>
> PS I also found these to provide some eye protection
> http://www.davida.co.uk/type.php?id=Visor_D4Vi9A
>
> On 02/12/2010 18:39, Robert L. Nuckolls, III wrote:
>> At 01:43 AM 12/2/2010, you wrote:
>>> Some worthy observations you've made Bob.
>>>
>>> I did some digging, and have attached an IM for the unit.
>>> Of interest in section "C" and "D" on pdf page 21:
>>>
>>> C. Speaker connection
>>> A 4 to 8 Ohm speaker can be connected to audio output P1- 1AF-asym.
>>> CAUTION : The magnetic field of a speaker influences the magnetic
>>> compass.
>>> When choosing the mounting point, a minimum distance of 1.3 m
>>> must be maintained between the speaker and the magnetic compass.
>>
>> Yeah . . . those recommendations were written
>> based on magnetic interference studies done
>> many moons ago when it was common practice
>> to mount a speaker in the cabin overhead.
>> Believe me, those were CHEAP speakers and
>> not terribly well shielded magnetically.
>> Further, there was no way you could get 1.3M
>> separation from the whisky compass . . . but
>> that's another problem.
>>
>>> D. Headphone connection
>>> Up to two headphones with an impedance of 600 Ohm can be connected to
>>> the audio output P1 - 2,3 AF-HI/LO.
>>
>> It may well be that the speaker/headset configuration
>> Peter is proposing won't drive from the headset
>> output of the radio. In this case, some amplification
>> is called for.
>>
>> I've been using a number of pre-packaged
>> amplifiers off ebay . . . very reasonably
>> priced. Here's an example that can be
>> had for $6 postage paid.
>>
>> *http://tinyurl.com/3a6oy7x*
>>
>> It needs to be boxed and power conditioned
>> for attaching to a DC bus . . . and probably
>> some gain setting resistors . . . but
>> a quick and dirty way to get substantial
>> boost to a stereo headset using low
>> impedance "speakers".
>>
>> Thanks for the manual. I've added it to my
>> manufacturer's data library.
>>
>> Bob . . .
>>
>>
>> *
>>
>> *
> *
>
> *
Message 9
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Subject: | Re: Headphone impedance |
At 05:11 PM 12/2/2010, you wrote:
>Also found user's guide for the ebay amp
>
><http://www.sure-electronics.net/download/AA-AB3213X_Ver1.0_EN.pdf>http://www.sure-electronics.net/download/AA-AB3213X_Ver1.0_EN.pdf
>
>catalogue here
>
><http://www.sureelectronics.net/Amplifier.pdf>http://www.sureelectronics.net/Amplifier.pdf
Thanks for the links. I've used several devices
from this firm. They're an excellent value and
perform as advertised.
Bob . . .
Message 10
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Subject: | Re: Headphone impedance |
At 03:58 PM 12/2/2010, you wrote:
Thanks for all of the input!
I would like to use the standard headphone output from the radio as
its already wired in - and I didn't even wire up the speaker pin from
the radio, that would also make the set up transferable to other aircraft.
The only way you can make this 100% transportable is
to add the necessary electronics to make your headset
EMULATE the standard headset. I.e., 600 ohms of load.
Back in the days I was burning my fingers and
sniffing the smoke over my first soldering iron,
the 'standard' headset was 2000 ohms impedance.
These integrated well with popular crystal and vacuum
tube radios.
2K headsets are no longer made in volume and expensive.
However, there are PLENTY of low impedance headsets
for as little as $1 a pair that work with modern
entertainment devices. A few years ago, I designed
a small battery powered amplifier with a 2K input
impedance and adjusted the gain such that similar
signals produced the same sounds from the headsets.
I.e., the modern el-cheapo headsets could be used
on homebrew projects with similar performance as
headsets of yesteryear.
- Its likely that an aviation radio headset output would overdrive
these speakers
. . . probably UNDER-DRIVE. The electronics within
the radio simply may not be capable of delivering
the necessary energy into the lower impedance
devices.
(resulting in poor volume control and possibly poor quality
output), and may suffer some damage to the radio audio amplifier (unlikely).
. . . mostly. The probable effect is that the received
audio will be heard but an severely reduced volume.
- To use these speakers/phones I will probably need an audio
isolation amplifier (made as described in Bob's note)
Quite likely. Further, if you're really interested
in moving across airplanes with this, then your
"adapter" may want to be a fat lump in the cordage
for the speaker/microphone set.
- Alternatively an amp from ebay may suffice ( for $6 seems a no
brainer :-) ) - but may require some power conditioning (interesting
that specs say 4.5v, but legend on board says 12v).
The major concern is for conducted noise and transient
voltages. You'll want to use a three-terminal regulator
to "step" down the 14v bus to say 9 volts. The regulator
will provide the isolation from transients and very good
filtering of bus noises.
and also some gain setting resistors [how do I calculate the value?]
Cut and try during the brass-board phase.
- To use the electret mic I will have to build a circuit per Bob's sketch.
This too will need to be brass-boarded and checked
on the bench. Do you have a harness to run the radio
on the workbench?
I think there are are potentially 3 ways ahead.
1. Buy amp above and start making mic circuit (perhaps gives the
ability to add an ipod input in the future)
Recommended.
2. Cannibalise an old headset (at least all the components should match)
Risky for mechanical issues. If you have mic and
headset components with a good track record and they
fit the helmet . . . then 80% of the battle is won.
3. Use the Halo headset for the time being and just figure out
sticking the ear plugs in my ears with the helmet around my neck ...
Ugh!
Bob . . .
Bob . . .
Message 11
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Subject: | Remote Power control for Aircraft PreHeater |
Does anyone have a good solution for Internet/Web accessible
power control for your aircraft sump/cylinder preheat?
My personal preference would be something that offers SSH
access, that I can log in and power on. Web would work too.
It's easy enough to find network power controls that look
to be plenty good, if you spend >$250. There are others
down just over $100, but some that I find have 6A ratings,
and I'd feel more comfortable with something that can
handle a good 10A even though that's far more than the
heater should use.
I do have a PC in the hangar that does security cam
recording and such, so another option would be a USB
controlled or home automation device.
I guess what I'm hoping for is a good solution that
people have used successfully....since I know a few
various ways to do it...and would like to know cost effective
ways if possible.
--
Tim Olson - RV-10 N104CD
do not archive
Message 12
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Subject: | PC board for avionics ground bus |
Anyone know if manufactured PC boards are available, such as those found in
this photo of a 37-pin D-sub connector used as an avionics ground bus?
http://www.aeroelectric.com/Pictures/Grounding/AVG_RA.jpg
I could certainly "roll my own," but if they are available someplace, I'd
just as soon buy one.
Thank in advance!
Buck Wyndham
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