Today's Message Index:
----------------------
1. 09:30 AM - Matronics.com access? (Robert L. Nuckolls, III)
2. 09:43 AM - Re: stray RF (Robert L. Nuckolls, III)
3. 09:45 AM - Re: Matronics.com access? (Robert L. Nuckolls, III)
4. 09:56 AM - Re: Matronics.com access? (Robert Borger)
5. 10:11 AM - Re: Matronics.com access? (ROGER & JEAN CURTIS)
6. 10:28 AM - Re: stray RF (James Robinson)
7. 11:08 AM - Heat Sink necessary? (jonlaury)
8. 11:41 AM - Z-31B Ground Power Contactor Diode (jonlaury)
9. 12:14 PM - Re: Heat Sink necessary? ()
10. 12:15 PM - Re: HLMP-2685 multi-LEDs off LR3C (James Kilford)
11. 12:38 PM - Re: Matronics.com access? (Dale Ellis)
12. 01:07 PM - Re: Microphone levels (B Tomm)
13. 01:08 PM - Re: Heat Sink necessary? (Robert L. Nuckolls, III)
14. 02:29 PM - Re: Z-31B Ground Power Contactor Diode (Robert L. Nuckolls, III)
15. 02:34 PM - Re: Microphone levels (Robert L. Nuckolls, III)
16. 02:48 PM - Re: Microphone levels (Ron Quillin)
17. 04:35 PM - Re: Microphone levels (Robert L. Nuckolls, III)
18. 04:52 PM - Re: Microphone levels (Robert L. Nuckolls, III)
Message 1
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| Subject: | Matronics.com access? |
Is anyone having trouble accessing http://matronics.com
Bob . . .
Message 2
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At 11:18 PM 7/5/2010, you wrote:
>Hi Bob
>I have recently developed a problem when I transmit my VSI and other
>features on my Cheltons goes crazy. I have added a engine monitor
>EI MVP-50 recently. Is there a way to isolate the cause. This is a
>recent occurance No prior problem for 350 hrs
A high-probability possibility is that a feed line
shield has become detached at one end or the other
on your comm antenna. A simple inspection may suffice.
An organized troubleshooting effort suggest you
dummy load the transceiver at the back of the tray
with a device like this:
http://aeroelectric.com/Pictures/Tools/RF_Antenna_Test_Tools/DummyLoad.jpg
See if the problem goes away. If so, then
move the dummy load to the other end of the
feedline. You'll need a male-male adapter, a
t-connector can be used too. Try again to see
if the problem goes away or is still there.
If the problem does not manifest with either
dummy load experiment, then it's likely that
something has changed in system conditions
for the Cheltons. But I'm betting it's a feed
line problem.
Bob . . .
Message 3
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| Subject: | Re: Matronics.com access? |
At 09:26 AM 7/6/2010, you wrote:
><nuckolls.bob@aeroelectric.com>
>
>Is anyone having trouble accessing http://matronics.com
>
I think the servers were down for a period of time since
midnight last night but they seem to be up now. All is
right with the world . . .
Bob . . .
Message 4
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| Subject: | Re: Matronics.com access? |
Bob,
Yup, it was down for a while but seems to be back up now.
Bob Borger
On Jul 6, 2010, at 9:26, Robert L. Nuckolls, III wrote:
>
> Is anyone having trouble accessing http://matronics.com
>
>
>
>
> Bob . . .
>
>
>
>
Message 5
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| Subject: | Matronics.com access? |
Is anyone having trouble accessing http://matronics.com
Bob . . .
Seems to be OK for me
Roger
Message 6
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Thanks Bob!!!!
James Robinson
Glasair lll N79R
Spanish Fork UT U77
________________________________
From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
Sent: Tue, July 6, 2010 10:45:17 AM
Subject: Re: AeroElectric-List: stray RF
<nuckolls.bob@aeroelectric.com>
At 11:18 PM 7/5/2010, you wrote:
> Hi Bob
> I have recently developed a problem when I transmit my VSI and other features
>on my Cheltons goes crazy. I have added a engine monitor EI MVP-50 recently.
>Is there a way to isolate the cause. This is a recent occurance No prior
>problem for 350 hrs
A high-probability possibility is that a feed line
shield has become detached at one end or the other
on your comm antenna. A simple inspection may suffice.
An organized troubleshooting effort suggest you
dummy load the transceiver at the back of the tray
with a device like this:
http://aeroelectric.com/Pictures/Tools/RF_Antenna_Test_Tools/DummyLoad.jpg
See if the problem goes away. If so, then
move the dummy load to the other end of the
feedline. You'll need a male-male adapter, a
t-connector can be used too. Try again to see
if the problem goes away or is still there.
If the problem does not manifest with either
dummy load experiment, then it's likely that
something has changed in system conditions
for the Cheltons. But I'm betting it's a feed
line problem.
Bob . . .
Message 7
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| Subject: | Heat Sink necessary? |
Using a 25a bridge rectifier for dual power sources for EFI. The injectors might
pull 10a, worst case. For normal ops, 6a.
Is heat sinking necessary for the rectifer?
Thanks,
J
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=303922#303922
Message 8
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| Subject: | Z-31B Ground Power Contactor Diode |
In Z-31B, I'm using a continuous duty contactor with one coil post, like the one
shown in the diagram and labled"Existing Battery Contactor", for a Grd. Pwr.
Contactor.
I'm unsure about where to place and how to orient the diode for a GP jack when
using the CD contactor.
Thanks for any help,
J
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=303931#303931
Message 9
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| Subject: | Heat Sink necessary? |
Jon,
You are mixing supply and demand (but that's ok). Normally it is
suggested a heat sink be used for a sink load of 20A or more. Since your
hardware is bigger than your load you could try it without. If it is
continuous load you may want to monitor the rectifier temperature to be
sure you're in limits. The manufacturer should publish that.
If you're at all concerned about temperature, just add a heat sink. If
the heat sink sets you back wait till you see the price at the gas pump.
Wow! The poor man's option is to mount it on a piece phenolic block
which you'll find does little for heat dissipation but is virtually
indestructible should your diode take to glowing in flight. You can cut
some grooves in the top of the block to allow air to travel underneath
the rectifier. You can also buy one of those computer fans and a frame
for about a $1.00 to point in the general direction. I have a variety
pack of those stick on thermometers that lets one visualize surface
temps. Could be handy for something like this. Most of this is much more
fuss than just installing the heat sink.
Hey, what kind of injectors pull 10A? I suppose you mean the ignition
module.
Enjoy,
Glenn E. Long
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
jonlaury
Sent: Tuesday, July 06, 2010 2:08 PM
Subject: AeroElectric-List: Heat Sink necessary?
<jonlaury@impulse.net>
Using a 25a bridge rectifier for dual power sources for EFI. The
injectors might pull 10a, worst case. For normal ops, 6a.
Is heat sinking necessary for the rectifer?
Thanks,
J
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=303922#303922
Message 10
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| Subject: | Re: HLMP-2685 multi-LEDs off LR3C |
Bob,
Just to feed back to you and anyone on the list who might fancy using
the HLMP-2685 as a snazzy LED alt. warn. light for the LR3C regulator,
I'd like to report the following:
It works quite well putting the 8 LEDs of the HLMP in two parallel
banks of 4 resistors in series, i.e. four LEDs on one side, in series,
put in parallel with the other four LEDs on the other side, those also
put in series. I put a current-limiting resistor of 440 ohms works
well. In fact, it was two 220 ohm resistors in series, but then I
don't have much of a resistor selection...
This arrangement seems to check out okay, and looks to be about the
right brightness. I might tweak it a little bit at some point. When
the warning light is "off", I can't discern any light from the HLMP,
and indeed on the bench I can discern no light from it at 6.0V. For
day time it looks good, though it might also be too bright for night
time use.
FWIW!
Thanks for your guidance on this matter.
James
On Sun, Apr 11, 2010 at 12:28 PM, James Kilford <james@etravel.org> wrote:
> Bob,
>
> That's great, thank you. It gives me a good place from which to experiment.
>
> James
>
> On Thu, Apr 8, 2010 at 2:04 PM, Robert L. Nuckolls, III
> <nuckolls.bob@aeroelectric.com> wrote:
>> <nuckolls.bob@aeroelectric.com>
>>
>>
>>>
>>>
>>> http://parts.digikey.com/1/parts/681506-led-lt-bar-hi-eff-red-8led-dip-hlmp2685.html
>>>
>>> I'd like to hook one of these to the LR3C regulator instead of the
>>> supplied filament lamp, so that it can go into the annunciator panel
>>> too.
>>>
>>> I've been trying to trace a schematic of Bob's, which I'm sure I've
>>> seen, of how to use an LED instead of a filament lamp with the LR3C,
>>> as a starting point. I can't find it, and the resistor values would
>>> be different in any case, so can anyone throw any light on to how to
>>> use one of these 8-LED devices with the LR3C?
>>
>> The schematic I published is at:
>>
>> http://aeroelectric.com/Pictures/Schematics/LR3_LV_Led_1.jpg
>>
>> Your application will take some experimentation.
>> You can try paralleling all the LEDs and seeing how
>> well you can excite the array and still have uniform
>> illumination. You may find that you need to treat
>> them as separate LEDs.
>>
>> Just be aware that LR3 lamp driver is never completely
>> "OFF". The off current is too low to get any light
>> from a bulb but it will cause an LED to glow at a
>> reduced intensity. Hence the paralleling resistor to
>> get the LED to mimic a lamp more closely.
>>
>> Bob . . .
>>
>>
Message 11
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| Subject: | Re: Matronics.com access? |
No problem from here
no not archive
On Tue, Jul 6, 2010 at 10:26 AM, Robert L. Nuckolls, III
<nuckolls.bob@aeroelectric.com> wrote:
> <nuckolls.bob@aeroelectric.com>
>
> Is anyone having trouble accessing http://matronics.com
>
>
> Bob . . .
>
>
Message 12
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| Subject: | Microphone levels |
Bob,
My interface circuit which brings a line level output through an impedance
matching transformer to the mic input of the aircraft radio may need to go
through a capacitor to block the DC bias voltage coming from the radio from
getting to the output of the matching transformer. Do you agree with this
method and can you recommend a value for this cap?
Bevan
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L.
Nuckolls, III
Sent: Monday, July 05, 2010 3:26 PM
Subject: Re: AeroElectric-List: Microphone levels
--> <nuckolls.bob@aeroelectric.com>
At 03:04 PM 7/5/2010, you wrote:
>--> <fvalarm@rapidnet.net>
>
> Bob,
>
>Would you expect that the microphone output level from a standard
>Aviation headset to be similar/ or even the same as a standard handheld
>audio microphone as used with a professional sound board?
No. Aircraft microphones are victim to legacy compatibility
standards that emulate the original carbon granule microphones
(like those in telephones through the 70s).
http://en.wikipedia.org/wiki/Carbon_microphone
The audio output is not only very high (as much as 1 vrms) it is
generated with a power supply delivered by the transmitter.
Hence, most aircraft microphones have active electronics so
that modern TINY voltage microphones can dress up like
a carbon mic.
> I don't own an audio
>meter but just need to be close for a non-aircraft related project.
Sound boards are generally set up to accept 100 mV pk-pk
(30 mV rms) output from dynamic mics delivered on twisted pairs.
Bob . . .
Message 13
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| Subject: | Re: Heat Sink necessary? |
At 01:07 PM 7/6/2010, you wrote:
>
>Using a 25a bridge rectifier for dual power sources for EFI. The
>injectors might pull 10a, worst case. For normal ops, 6a.
>Is heat sinking necessary for the rectifer?
yes . . . but simply mounting it to a metallic
surface on the airplane will be sufficient.
10A on any one leg of the device will dissipate
about 7 watts of heat that is easily managed by
most metal surface mounting situations.
Doing in-situ temperature measurements on the
molded bridge rectifier is VERY difficult. There's
no thermally integral metal surface available for
sampling. You'd need to bury a tiny-wire thermocouple
in the mounting under the rectifier assembly.
You can measure the temperature of the sheet metal
directly opposite the rectifier and make some
assumptions about thermal resistance of the
mounting . . . but it's more fuss than you'd
probably want to experience. 10A doesn't present
much of a challenge to a device with a metal
heat-sink interface. Use a little 'heat sink'
grease under it when mounting.
http://www.radioshack.com/product/index.jsp?productId=2102858
Bob . . .
Message 14
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| Subject: | Re: Z-31B Ground Power Contactor Diode |
At 01:39 PM 7/6/2010, you wrote:
>
>In Z-31B, I'm using a continuous duty contactor with one coil post,
>like the one shown in the diagram and labled"Existing Battery
>Contactor", for a Grd. Pwr. Contactor.
>
>I'm unsure about where to place and how to orient the diode for a GP
>jack when using the CD contactor.
The banded end of the diode connects to the
"BAT" terminal of the contactor which in turn
faces incoming power from the ground power
connector.
The other end of the diode goes to the small
coil terminal which is switched to ground
to energize the contactor and bring ground
power onto the bus.
Bob . . .
Message 15
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| Subject: | Microphone levels |
At 02:58 PM 7/6/2010, you wrote:
>
>Bob,
>
>My interface circuit which brings a line level output through an impedance
>matching transformer to the mic input of the aircraft radio may need to go
>through a capacitor to block the DC bias voltage coming from the radio from
>getting to the output of the matching transformer. Do you agree with this
>method and can you recommend a value for this cap?
Some experimentation is probably called for. You
need to find a resistor value that becomes a
'dummy microphone'. The resistor probably wants
to have 2-3 volts dropped across it while the
transmitter is 'talking'.
Then make sure the effective output impedance and
signal level of your transmit audio source can
drive the necessary signal into this load . . .
3 v pk-pk is probably a good upper bound to
strive for. Then pick a capacitor who's reactance
at say 100Hz is about 1/10 that of the sum of
dummy load resistor + source output impedance.
Bob . . .
Message 16
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| Subject: | Microphone levels |
At 14:36 7/6/2010, you wrote:
>signal level of your transmit audio source can
> drive the necessary signal into this load . . .
> 3 v pk-pk is probably a good upper bound to
> strive for.
Without grabbing my scope, 3Vpp --sounds-- a bit hot for a mic input.
Is that value a typo?
Ron Q.
Message 17
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| Subject: | Microphone levels |
At 04:46 PM 7/6/2010, you wrote:
>At 14:36 7/6/2010, you wrote:
>>signal level of your transmit audio source can
>> drive the necessary signal into this load . . .
>> 3 v pk-pk is probably a good upper bound to
>> strive for.
>
>Without grabbing my scope, 3Vpp --sounds-- a bit hot for a mic input.
Nope. That's what can come out of an aircraft microphone
the emulates the legacy carbon mic. Of course, REAL
carbon microphones are exceedingly rare in service now.
Just for grins, put your scope on the mic line of
a headset and see what kinds of signals can be
seen there. They may have migrated down over the
years . . .
Bob . . .
Message 18
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| Subject: | Microphone levels |
At 04:46 PM 7/6/2010, you wrote:
>At 14:36 7/6/2010, you wrote:
>>signal level of your transmit audio source can
>> drive the necessary signal into this load . . .
>> 3 v pk-pk is probably a good upper bound to
>> strive for.
>
>Without grabbing my scope, 3Vpp --sounds-- a bit hot for a mic input.
Nope. That's what can come out of an aircraft microphone
the emulates the legacy carbon mic. Of course, REAL
carbon microphones are exceedingly rare in service now.
Just for grins, put your scope on the mic line of
a headset and see what kinds of signals can be
seen there. They may have migrated down over the
years . . .
P.s. Just checked some links as follows:
http://www.capitalavionics.com/tip_0909.asp
http://tinyurl.com/24g4wjf
and a number of others that 'specd' aircraft
mics for sensitivity, current draw, bias voltage
but failed to call out the output voltage
present when those specs are being satisfied.
I think it was DO170 that talks industry
specifics.
I did see an anecdotal reference to 100-500 mv
which would translate to 300-1500 mv pk-pk.
Same ball park. We used to design for 3v pk-pk
to have zero risk of clipping . . . at least in
THAT part of the circuit!
Bob . . .
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