Today's Message Index:
----------------------
1. 04:51 AM - Re: Diagnostic Help Please: Audio is Weak and Scratchy (Jared Yates)
2. 12:15 PM - Re: Diagnostic Help Please: Audio is Weak and Scratchy (Christopher Cee Stone)
3. 12:30 PM - transmitter power attenuator (Christopher Cee Stone)
4. 12:42 PM - Re: Re: LED heatsink material? (Christopher Cee Stone)
5. 03:18 PM - Re: transmitter power attenuator (Robert L. Nuckolls, III)
6. 06:36 PM - Re: transmitter power attenuator (Robert L. Nuckolls, III)
7. 06:49 PM - Re: transmitter power attenuator (Robert L. Nuckolls, III)
8. 07:08 PM - Re: transmitter power attenuator (BobsV35B@aol.com)
9. 09:18 PM - Dolphin Electrical Wire Connectors (Owen Baker)
Message 1
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| Subject: | Re: Diagnostic Help Please: Audio is Weak and Scratchy |
Thank you very much Charlie, I'll try those procedures and report back when complete.
On Apr 5, 2013, at 20:46, Charlie England <ceengland7@gmail.com> wrote:
>
> On 04/05/2013 03:40 PM, Jared Yates wrote:
>>
>> I've been testing my audio system and have encountered poor
>> performance. Does anyone have any suggestions for what to check?
>> Here is the problem:
>>
>> All audio through the headsets is too quiet, and pretty scratchy. This
>> applies to radio reception, intercom audio, Dynon voice out, and music
>> input. With the intercom volume, headset volume, and individual device
>> volume all the way up, the total volume is about where I would want to
>> have it with 25% volume selected instead. The issue seems to afflict
>> each of the various inputs to a similar degree.
>>
>> Here is the setup:
>> New construction, wired by me (a non-professional, so anything is possible)
>> The airframe is a steel tube 4-place fuselage with the mic and audio
>> headset jacks isolated from ground, as verified by voltmeter
>> continuity checks.
>> I used shielded cables to connect the intercom and the mic and stereo
>> phone jacks, with the shields connected at intercom end to each other
>> and not connected to anything at the jacks.
>> I have a self-assembled AEC 9009 Audio Iso Amp handling VHF nav audio
>> on one channel, dynon warnings on one channel, left music in on one
>> channel, and right music in on one channel, with the 9009's output
>> going into the intercom aux input
>> The intercom is a Flightcom 403, with the pilot wires going to the
>> left front seat, copilot wires to the right front seat, and passenger
>> jacks to the back two seats.
>> The GNS430 is the only radio, with com audio routed directly to the
>> intercom per the intercom directions.
>> I'm testing with two known-good David Clark headsets (one stereo, one
>> mono) and one brand new Lightspeed headset, all with freshly buffed,
>> shiny connectors.
>> I'm using battery power only, since the engine is not installed
>> presently. I've tried the battery by itself and the battery with the
>> charger connected. The voltage range is about 13v to 14v for those
>> two cases, but I can't see that changing from one to the other makes
>> any difference in the audio system issues.
>>
>> Here is what I have tried so far with no improvements:
>> First, I unplugged aec9009. I lost the channels that run through it,
>> but the remaining intercom and VHF com audio were still the same.
>> Then I swapped intercom for the bypass plug that I built per the
>> intercom manual. this plug is designed to connect the pilot seat
>> jacks directly to the radio, so that the airplane can still function
>> as a single-place if the intercom is removed entirely. As with the
>> 9009, I lose intercom function in this configuration (as I should),
>> but the vhf com audio is still weak and scratchy.
>> I tried changing the Headsets around in various combinations to
>> various seats with no appreciable change.
>> I changed out the volume resistors in the AEC9009 to increase the
>> volume of those channels, and the volume did go up on the channel in
>> question, but the quality really suffered.
>> I'm not really sure what to try next. Does anyone have any
>> suggestions for what to check?
> The fuzzy part sounds like some segment in the audio chain is being overdriven
by a source, or is being asked to supply more than it's capable of giving. The
low level could be too much of a load on the output (load impedance too low).
A partial short to ground (from an audio 'hi' to an audio 'Lo', or to the chassis)
is the 1st thing that comes to mind. Having both fuzzy & low volume from
multiple sources *might* mean that you have two or more outputs trying to feed
into each other, with no isolation resistors between them. (This will make
all affected outputs 'think' that they are effectively shorted to ground because
each is trying to drive a very low impedance load.)
>
> So to proceed, 'Divide & conquer.'
>
> It's extremely unlikely that you have the same problem with every source, so
job one is eliminating the known-good items. I'd get a set of clip leads, and
extra phone jack, & start testing each source by itself, without it connected
to any other component. Isolate the output line (typically 'audio hi' on the hookup
diagram) from the rest of the plane. Hook a clip lead from that wire to
the tip terminal of your spare jack. Hook another clip lead from the ground ('audio
Lo') to the shield (ground) terminal of the jack. Plug in a known-good headset
& listen to that source. Sound ok? If not troubleshoot settings, ground
paths, etc. If good, move to the next source & repeat. Annddd repeat, until you've
checked all or until you find a bad component.
>
> If all is good, hook one (and only one) source to the iso amp & move your test
jack to the iso amp's output (with it hooked to nothing else). If bad, there's
your problem. All good? that means the iso amp is almost certainly good, too.
>
> Hook the iso amp to the intercom's input again (with nothing else hooked to the
input). Move the test jack to the intercom's output (with nothing else hooked
up to the output lead). Listen again. If bad, check intercom settings (especially
if there is an internal gain setting or aux input volume control in the
intercom).
>
> All good? Without hooking up the 430, add one component to the iso amp & check
for level/quality at the intercom output. (We've actually skipped a few steps
by doing this, but if one iso input is good, odds are high that all will be
good.)
>
> All sources (except 430) good? Use your test jack to check the 430, with its
output connected to nothing but the test jack. Bad? There's your problem. Good?
Proceed.
>
> Now look at how the 430 ties to the intercom. In your message, you say that the
iso amp is hooked direct to the intercom. Is this a separate input on the intercom?
It probably is, but if it's tied to the same input with the iso amp,
that might well be your problem. Different input? Move your test jack to the intercom
output & listen to the 430 through the intercom. Bad? Re-check wiring
& intercom settings, then check the intercom itself, if possible. Still good?
Re-check your headphone wiring harness in the plane.
>
> Having said all that, I'll say this: I've worked on a couple of 430 installations
for friends, & they can be real snakes to troubleshoot. The most common issue
is ground pins on the d-Sub connectors. There are quite a few, & if you miss
one, stuff isn't going to work (not every ground terminal is common to every
other ground terminal in those d-Sub connectors). On one system, I spoke with
directly to a Garmin factory tech while holding the installation manual in
my hand, and read off the pins that were connected. Even the Garmin tech failed
to mention a (ground) pin that needed to be connected.
>
> Charlie
> (pro audio tech, consumer electronics tech and industrial electronics tech in
various former lives)
>
>
>
>
Message 2
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| Subject: | Re: Diagnostic Help Please: Audio is Weak and Scratchy |
Jared...
One other potential low impedance fault is if using stereo headphone jacks
and connecting both tip and ring to audio high. When a mono headphone plug
is used it shorts the ring to audio lo (ground) and results in low or no
audio from the connected source(s).
Chris Stone
RV-8
On Sat, Apr 6, 2013 at 4:52 AM, Jared Yates <email@jaredyates.com> wrote:
> >
>
> Thank you very much Charlie, I'll try those procedures and report back
> when complete.
>
>
> On Apr 5, 2013, at 20:46, Charlie England <ceengland7@gmail.com> wrote:
>
> ceengland7@gmail.com>
> >
> > On 04/05/2013 03:40 PM, Jared Yates wrote:
> email@jaredyates.com>
> >>
> >> I've been testing my audio system and have encountered poor
> >> performance. Does anyone have any suggestions for what to check?
> >> Here is the problem:
> >>
> >> All audio through the headsets is too quiet, and pretty scratchy. This
> >> applies to radio reception, intercom audio, Dynon voice out, and music
> >> input. With the intercom volume, headset volume, and individual device
> >> volume all the way up, the total volume is about where I would want to
> >> have it with 25% volume selected instead. The issue seems to afflict
> >> each of the various inputs to a similar degree.
> >>
> >> Here is the setup:
> >> New construction, wired by me (a non-professional, so anything is
> possible)
> >> The airframe is a steel tube 4-place fuselage with the mic and audio
> >> headset jacks isolated from ground, as verified by voltmeter
> >> continuity checks.
> >> I used shielded cables to connect the intercom and the mic and stereo
> >> phone jacks, with the shields connected at intercom end to each other
> >> and not connected to anything at the jacks.
> >> I have a self-assembled AEC 9009 Audio Iso Amp handling VHF nav audio
> >> on one channel, dynon warnings on one channel, left music in on one
> >> channel, and right music in on one channel, with the 9009's output
> >> going into the intercom aux input
> >> The intercom is a Flightcom 403, with the pilot wires going to the
> >> left front seat, copilot wires to the right front seat, and passenger
> >> jacks to the back two seats.
> >> The GNS430 is the only radio, with com audio routed directly to the
> >> intercom per the intercom directions.
> >> I'm testing with two known-good David Clark headsets (one stereo, one
> >> mono) and one brand new Lightspeed headset, all with freshly buffed,
> >> shiny connectors.
> >> I'm using battery power only, since the engine is not installed
> >> presently. I've tried the battery by itself and the battery with the
> >> charger connected. The voltage range is about 13v to 14v for those
> >> two cases, but I can't see that changing from one to the other makes
> >> any difference in the audio system issues.
> >>
> >> Here is what I have tried so far with no improvements:
> >> First, I unplugged aec9009. I lost the channels that run through it,
> >> but the remaining intercom and VHF com audio were still the same.
> >> Then I swapped intercom for the bypass plug that I built per the
> >> intercom manual. this plug is designed to connect the pilot seat
> >> jacks directly to the radio, so that the airplane can still function
> >> as a single-place if the intercom is removed entirely. As with the
> >> 9009, I lose intercom function in this configuration (as I should),
> >> but the vhf com audio is still weak and scratchy.
> >> I tried changing the Headsets around in various combinations to
> >> various seats with no appreciable change.
> >> I changed out the volume resistors in the AEC9009 to increase the
> >> volume of those channels, and the volume did go up on the channel in
> >> question, but the quality really suffered.
> >> I'm not really sure what to try next. Does anyone have any
> >> suggestions for what to check?
> > The fuzzy part sounds like some segment in the audio chain is being
> overdriven by a source, or is being asked to supply more than it's capable
> of giving. The low level could be too much of a load on the output (load
> impedance too low). A partial short to ground (from an audio 'hi' to an
> audio 'Lo', or to the chassis) is the 1st thing that comes to mind. Having
> both fuzzy & low volume from multiple sources *might* mean that you have
> two or more outputs trying to feed into each other, with no isolation
> resistors between them. (This will make all affected outputs 'think' that
> they are effectively shorted to ground because each is trying to drive a
> very low impedance load.)
> >
> > So to proceed, 'Divide & conquer.'
> >
> > It's extremely unlikely that you have the same problem with every
> source, so job one is eliminating the known-good items. I'd get a set of
> clip leads, and extra phone jack, & start testing each source by itself,
> without it connected to any other component. Isolate the output line
> (typically 'audio hi' on the hookup diagram) from the rest of the plane.
> Hook a clip lead from that wire to the tip terminal of your spare jack.
> Hook another clip lead from the ground ('audio Lo') to the shield (ground)
> terminal of the jack. Plug in a known-good headset & listen to that source.
> Sound ok? If not troubleshoot settings, ground paths, etc. If good, move to
> the next source & repeat. Annddd repeat, until you've checked all or until
> you find a bad component.
> >
> > If all is good, hook one (and only one) source to the iso amp & move
> your test jack to the iso amp's output (with it hooked to nothing else). If
> bad, there's your problem. All good? that means the iso amp is almost
> certainly good, too.
> >
> > Hook the iso amp to the intercom's input again (with nothing else hooked
> to the input). Move the test jack to the intercom's output (with nothing
> else hooked up to the output lead). Listen again. If bad, check intercom
> settings (especially if there is an internal gain setting or aux input
> volume control in the intercom).
> >
> > All good? Without hooking up the 430, add one component to the iso amp &
> check for level/quality at the intercom output. (We've actually skipped a
> few steps by doing this, but if one iso input is good, odds are high that
> all will be good.)
> >
> > All sources (except 430) good? Use your test jack to check the 430, with
> its output connected to nothing but the test jack. Bad? There's your
> problem. Good? Proceed.
> >
> > Now look at how the 430 ties to the intercom. In your message, you say
> that the iso amp is hooked direct to the intercom. Is this a separate input
> on the intercom? It probably is, but if it's tied to the same input with
> the iso amp, that might well be your problem. Different input? Move your
> test jack to the intercom output & listen to the 430 through the intercom.
> Bad? Re-check wiring & intercom settings, then check the intercom itself,
> if possible. Still good? Re-check your headphone wiring harness in the
> plane.
> >
> > Having said all that, I'll say this: I've worked on a couple of 430
> installations for friends, & they can be real snakes to troubleshoot. The
> most common issue is ground pins on the d-Sub connectors. There are quite a
> few, & if you miss one, stuff isn't going to work (not every ground
> terminal is common to every other ground terminal in those d-Sub
> connectors). On one system, I spoke with directly to a Garmin factory tech
> while holding the installation manual in my hand, and read off the pins
> that were connected. Even the Garmin tech failed to mention a (ground) pin
> that needed to be connected.
> >
> > Charlie
> > (pro audio tech, consumer electronics tech and industrial electronics
> tech in various former lives)
> >
> >
> >
> >
>
>
Message 3
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| Subject: | transmitter power attenuator |
I saw a recent post from Bob discussing using a 100 ft piece of coax
connected to the comm antenna serving as an attenuator allowing for bench
testing of a comm radio (xmit) without connecting to a conventional antenna.
My question is, will this also work for a transponder?
I am testing a new panel but do not have any antennas mounted to the the
airframe and need to verify proper operation of each radio. I do have a
dipole antenna (tuned for 118-136 Mhz) mounted on the roof of the shop I
use for testing operation of the comms. But I haven't found any procedure
for testing the transponder and ADS-B UAT which are 1090 Mhz and 978 Mhz
without using their respective antennas.
Chris Stone
RV-8
GNS 430, AFS EFIS, Navworx ADS-B, Val comm, PMA 4000
Message 4
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| Subject: | Re: LED heatsink material? |
Eric...
Great applied 'finger on' indicator scale. And makes access to check those
buried components a breeze!
Verified with my IR non contact thermometer... I now have a
NIST calibration certificate on my right index finger.
Chris Stone
do not archive
On Fri, Apr 5, 2013 at 6:07 AM, Eric M. Jones <emjones@charter.net> wrote:
> emjones@charter.net>
>
>
> > Tape this into your toolbox. These are for surfaces touched with a
> non-calloused finger, not ambients.
> >
> > Cool: 100 degC
> >
> > You can estimate between these numbers quite well.
>
>
> There was some sort of error in this posting which involved the "more
> than" and "less than" symbols. I tried to delete it but it got through
> anyway. Here it is again (without the symbols):
>
> Tape this into your toolbox. These are for metal surfaces touched with a
> non-calloused finger, not ambients.
>
> Cool: 30 degC
> Warm: 40 degC
> Uncomfortably Hot: 50 degC
> As hot as you can touch: 60 degC
> Immediately painful: 70 degC
> Will blister skin: 100 degC
>
> You can estimate between these numbers quite well.
>
> Matt: If you can delete the previous post I'd appreciate it.
>
> --------
> Eric M. Jones
> www.PerihelionDesign.com
> 113 Brentwood Drive
> Southbridge, MA 01550
> (508) 764-2072
> emjones(at)charter.net
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=397893#397893
>
>
Message 5
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| Subject: | Re: transmitter power attenuator |
At 02:30 PM 4/6/2013, you wrote:
>I saw a recent post from Bob discussing using a
>100 ft piece of coax connected to the comm
>antenna serving as an attenuator allowing for
>bench testing of a comm radio (xmit) without
>connecting to a conventional antenna.
>
>My question is, will this also work for a transponder?
Even better yet. Attenuation at 1050 is a LOT higher
than at 126.
>I am testing a new panel but do not have any
>antennas mounted to the the airframe and need to
>verify proper operation of each radio. I do
>have a dipole antenna (tuned for 118-136 Mhz)
>mounted on the roof of the shop I use for
>testing operation of the comms. But I haven't
>found any procedure for testing the transponder
>and ADS-B UAT which are 1090 Mhz and 978 Mhz
>without using their respective antennas.
Hmmmm . . . that's a bigger problem and I'm
not conversant with those systems. Waaayyy back
when I used to have one of those AirSport eavesdroppers to
check a transponder for gross functionality. You could
lay a 110v drill motor on the ground under the xponder
antenna and tie it into the ON position with a rubber
band.
Noise from the motor would tickle the transponder
into fits of apoplexy . . . it would begin to
squirt out mode c replies which could be read
on the AirSport faceplate. Kinda handy sometimes.
But all that newfangled stuff . . . I don't know.
Bob . . .
Message 6
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| Subject: | Re: transmitter power attenuator |
Here's the AirSport Corporation electro-whizzy. Looks
like they are still in business. Haven't had any direct
contact with them in 10-15 years.
http://tinyurl.com/ca8mgkv
Bob . . .
Message 7
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| Subject: | Re: transmitter power attenuator |
Here's the AirSport Corporation electro-whizzy. Looks
like they are still in business. Haven't had any direct
contact with them in 10-15 years.
http://tinyurl.com/ca8mgkv
Bob . . .
Message 8
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| Subject: | Re: transmitter power attenuator |
Good Evening Bob,
I bought one a year or so ago. The main thing I use it for is to be sure
what my transponder is sending to the FEDs.. I set it on top of my
glareshield and I can see what my stuff is telling the FED!
I like it, but would prefer that it be smaller.
Happy Skies,
Old Bob
In a message dated 4/6/2013 8:50:35 P.M. Central Daylight Time,
nuckolls.bob@aeroelectric.com writes:
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<nuckolls.bob@aeroelectric.com>
Here's the AirSport Corporation electro-whizzy. Looks
like they are still in business. Haven't had any direct
contact with them in 10-15 years.
http://tinyurl.com/ca8mgkv
Bob . . .
Message 9
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| Subject: | Dolphin Electrical Wire Connectors |
4/7/2013
Hello Again Bob Nuckolls, I thank you for your response copied below and
I accept your recommendation.
As an alternate means of connecting individual small wires together I
seem to recall a technique of using D sub pins and sockets crimped onto
the ends of the two wires and heat shrink tubing used to help hold the
wires together.
Is there anything published on using that technique?
Thank you,
=98OC=99 Baker
===
Bob Nuckolls wrote:
I think somebody else on the list commented on those. Those
are intended to telecommunications wiring in buildings.
Except for ribbon cable connectors INSIDE black boxes,
insulation displacement technology has never taken a
foothold in aviation. I don't think I'd recommend
them for airframe systems wiring.
Oh yea, one of the ELT manufacturers used RJ series
ID connectors on ordinary telephone wire to connect
their panel mounted controls with the remote mounted
transmitter. Haven't heard anything about lack of
success for that decision . . . but still . . . their
suitability to task is limited.
Bob . . .
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