Today's Message Index:
----------------------
1. 05:25 AM - B&C SD 8 Alternator (Charles Brame)
2. 05:33 AM - Re: Nav/com 'acoustic feedback' (Miskelly, Francis G)
3. 06:45 AM - strobe whine noise (Ken)
4. 08:33 AM - Re: strobe whine noise (Miskelly, Francis G)
5. 09:25 AM - Re: strobe whine noise (Matt Prather)
6. 02:16 PM - Off Subject Question (Bill Bradburry)
7. 02:16 PM - Loss of essential bus (Ron Schreck)
8. 04:34 PM - P-Lead Routing (Michel Creek)
9. 05:53 PM - Re: Aeroelectric Connection Book (Robert L. Nuckolls, III)
10. 07:47 PM - Re: Aeroelectric Connection Book (Jim Jewell)
Message 1
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| Subject: | B&C SD 8 Alternator |
Harley, et al,
I have a friend with a Pitts who has a SD 8 as his only power source
other than the battery. He has no electronics other than a radio and
the starter. His SD 8 is more than adequate to run the radio with
enough current left over to charge the battery.
The only concern I would have with the SD 8 or the SD 20 as a sole
power source is that both require fairly high RPM to produce adequate
current for much of anything. Our usual high amp alternators produce
enough juice at idle to charge the battery.
Charlie Brame
RV-6A N11CB
San Antonio
--------------------------------------------------
> Time: 05:36:52 AM PST US
> From: Harley <harley@AgelessWings.com>
> Subject: AeroElectric-List: B&C SD 8 Alternator
>
>
> Morning, Everyone...
>
> Now that I'm dumping all my remaining vacuum instruments (the one I
> have
> left!) and the associated pump and gauge, and settling for an all
> electric panel (except for the static gauges), I am starting to
> look at
> alternator options.
>
> I've kept up on the past discussions here, and Bob's Connection info,
> and have a pretty good
> idea of what's involved.
>
> But, I just noticed the B&C model SD-8 alternator that fits on the
> vacuum pump pad! What a great replacement for a gasket and a cover!
>
> I also see that Bob does mention it's use in one of his articles,
> but as
> a backup alternator.
>
> Seeing that the original Long Ez plans call out an alternator only
> as an
> option if you plan on IFR or night flying, or if you use a starter,
> and
> strongly recommend just the VariEZE solar panel to keep the battery
> charged, has anyone here installed the SD-8 and used it as the main
> unit. It only has a maximum 10 amp output, and a nominal 8 amp, but I
> would think that would be enough to keep the battery charged and
> operate
> the newer low current instruments quite well.
>
> I have yet to calculate my panel's consumption (don't have all the
> instruments yet), let alone the plane's, so it's still in the planning
> stage. Open to all suggestions. Redundancy is always best, but if
> one
> can save some weight and still do the job (I also have two P-mags with
> their own generators so the engine should keep running on the
> electronic
> ignition even if the battery and alternator go down) then I'm all
> for it.
>
> Harley Dixon
>
Message 2
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| Subject: | Nav/com 'acoustic feedback' |
Thanks Matt
Answers (in italics) to your questions below
- Frank
________________________________
From: owner-aeroelectric-list-server@matronics.com on behalf of Matt
Prather
Sent: Wed 15/08/2007 23:27
Subject: RE: AeroElectric-List: Nav/com 'acoustic feedback'
<mprather@spro.net>
I'm still not sure whether it's electrical noise or acoustic noise -
since
covering the mic has some effect on the behavior. If it were just
acoustic, covering the mic should stop the noise. More questions:
I suspect its not acoustic as it doesn't affect my handheld ICOM and the
a/c is not that noisy
- Is the acoustic squelch on the intercom adjustable? Can you set the
threshold higher? Maybe pulling out the volume knob and turning it
adjusts that? Or is it dynamic/smart adjusting?
I don't know how to adjust the intercom volume. I presume it is
adjustible. Pulling out the volume knob takes off the automatic squelch.
There is no obvious knob to adjust the intercom vol.
- What kind of engine is it? Its a Lycoming 0-320 with 150hp
- Does it have separate ignition systems? Can you turn one off at a
time
(to help isolate electrical noise)? It has 2 mags and i've tried both
separately - no effect
- Can you turn the alternator off with the engine running? Turning off
alternator - no effect
- You probably answered this before, but with the engine off, does the
intercom appear to work properly? Speaking in the mic on one headset
yields sound coming from the other headset - using the radio sidetone?
With the engine off the radio is perfect. No intercom problems. Perfect
reception and transmit
- Are you able to transmit/receiver properly when the engine is off?
- Are the mic leads made with shielded wire? Mic leads are not
shielded. They are 2 twisted wires
- Do other aspects of the electrical system all appear to function
normally - bus voltage, nav signals, etc? All other parts of electrics
are fine
Bob often recommends powering from a separate battery the piece(s) of
equipment that are involved in the problem. A couple of lantern
batteries
could be used to power the radio while the engine is running.. If that
has any effect on the noise, it indicates that the problem is conducted
to
the radio via the power bus. Tried that from a separate 12V battery - no
effect
What would be slick for this kind of online debug process would be to
have
an online spreadsheet or form which could be used to document the
problem,
behaviors, and the things that have been tried in order to fix it..
Have
to ponder that a bit.
I've changed the antenna, power supply, headsets, earthed everything
possible and checked all the earths. The problem of feedback only occurs
when i plug in the mic jack when the engine is running. I have a
handheld ICOM which uses the same power supply and aerial yet it works
perfectly. It has no intercom.
I plan to disconnect the intercom this weekend to see whether the
problem disappears.
Regards,
Matt-
> 1. The radio is a Bendix/King KX155
> 2. It is approximately 1 year old. Don't know the model # but could
find
> out
> 3. It definately has an internal intercom but i've no links to
describe it
> 4. I didn't check whether the sound varied depending on where your
> head/headset is sitting, or by
> bending the wires around on the headset, or the wires to the jack but
it
> occurred with 3 separate headsets and on both pilot and co-pilot
outputs.
> Pretty sure its not a headset problem as same headsets work fine in
other
> planes
> 5. The noise gets worse with higher engine RPM but is very obvious
even at
> 1000 RPM. The character doesn't change - just its loudness
> Many thanks
> Frank
>
> ________________________________
>
> From: owner-aeroelectric-list-server@matronics.com on behalf of Matt
> Prather
> Sent: Mon 13/08/2007 22:29
> To: aeroelectric-list@matronics.com
> Subject: RE: AeroElectric-List: Nav/com 'acoustic feedback'
>
>
> <mprather@spro.net>
>
> Interesting.. I wasn't aware that any KX155 has intercom. Okay. I
see
> the manual says it has 500ohm aux inputs, but don't see any reference
to
> intercom. We're talking about a Bendix/King KX-155, right? Do you
have a
> link to a file which describes the feature?
>
> Does the sound vary depending on where your head/headset is sitting,
or by
> bending the wires around on the headset, or the wires to the jack?
>
> Is the frequency of the whine/feedback dependent on the engine RPM?
Or is
> it just a steady tone?
>
> I agree with item 3 (assuming an intercom).
>
>
> Regards,
>
> Matt-
>
>
>> Matt
>> 1. When i cover the mic with my hand (muff off) the character of the
>> feedback alters significantly but is not overall reduced. If i move
the
>> boom away from my mouth and around to the back of my head then the
>> feedback reduces but doesn't disappear. Its worse (louder) the closer
>> the
>> boom to my mouth. These symptoms occur on both left and right hand
>> headsets
>> 2. My KX155 has an internal intercom. I haven't tried to disconnect
it.
>> 3. Plugging in the mic jack should activate the intercom and the
>> transmit
>> on the radio (when PTT pressed)
>> 4. Remember the problem only occurs when the engine is running.
>> 5. Does anyone know how to adjust the mic gain (intercom volume
control)
>> on the KX155? Couldn't find this info in the installation manual.
>> Kind regards
>> Frank
>>
>>
>>
>>
>> ________________________________
>>
>> From: owner-aeroelectric-list-server@matronics.com on behalf of Matt
>> Prather
>> Sent: Mon 13/08/2007 20:12
>> To: aeroelectric-list@matronics.com
>> Subject: RE: AeroElectric-List: Nav/com 'acoustic feedback'
>>
>>
>>
>> <mprather@spro.net>
>>
>> Does it help if you cover the mic with your hand (both sides - pull
the
>> muff off)?
>>
>> I suspect that the input stage of your intercom is being overdriven
by
>> the
>> acoustic noise of the engine.
>>
>>
>>
>> Regards,
>>
>> Matt-
>>
>>> Thanks for your comments Ernest.
>>> I've double-checked all the grounds i could find. Even took the
whole
>>> harness out (which was new) and had it double-checked. Nothing
found.
>>> If its the intercom in the radio why does it not cause the same
problem
>>> when the engine is off?
>>> It only causes the problem when the engine is running
>>> Kind regards
>>> Frank
>>>
>>> ________________________________
>>>
>>> From: owner-aeroelectric-list-server@matronics.com on behalf of
Ernest
>>> Christley
>>> Sent: Mon 13/08/2007 15:04
>>> To: aeroelectric-list@matronics.com
>>> Subject: Re: AeroElectric-List: Nav/com 'acoustic feedback'
>>>
>>>
>>>
>>> <echristley@nc.rr.com>
>>>
>>> Miskelly, Francis G wrote:
>>>> The KX155 nav/com in my Glastar has 2 problems which may be
related.
>>>>
>>>> 1. Inserting the headphone jack i have near perfect reception.
>>>> However, when i insert the microphone jack there is a loud whine
>>>> suggestive of 'acoustic feedback'. Moving the boom away from my
mouth
>>>> reduces the whine. With a different headset it appears as lots of
>>>> static noise which again changes with position of the boom. I've
>>>> changed the aerial, power supply and checked all the earths. It
occurs
>>>> with either mag and when the generator is disconnected. It only
>>>> happens when the engine is running. The radio's been bench tested
and
>>>> passed as good.
>>>>
>>>> 2. Radio reception is good with just the headphone jack inserted.
>>>> However, insert the microphone jack and reception becomes very poor
or
>>>> disappears completely. I suspect the 'acoustic feedback' is raising
>>>> the automatic squelch which is cutting off the radio station
>>>>
>>>> Can anyone suggest an explanation and a solution!
>>>> Many thanks
>>>> Frank
>>> Since there is a problem with multiple headset, I would check the
jack
>>> first. The symptoms seem to imply some feedback from the mic to the
>>> audio. Look for a short or a broken ground. Beyond that, it would
>>> seem
>>> circuitry withing the intercom is fritzed, and it gets much more
>>> complicated.
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
<http://www.matronics.com/Navigator?AeroElectric-List>
Message 3
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| Subject: | strobe whine noise |
FWIW powering my strobes from separate batteries made no difference to
the audio whine that I was hearing from them. Adding some homemade
filter devices likewise had no effect so I guess I did not hit on the
best component values. I never did find a ground issue that I could
blame the problem on. And yet when I finally obtained and tried a cheap
automotive filter on the 12 volt feed to the strobes, the situation
improved markedly and I can no longer hear the strobes in flight. The
directions said to try reversing the filter leads for best effect. Sure
enough the filter only worked well in one direction. Grounding the
ground connection to the filter also had no effect.
Ken
>snip
>Bob often recommends powering from a separate battery the piece(s) of
>equipment that are involved in the problem. A couple of lantern batteries
>could be used to power the radio while the engine is running.. If that
>has any effect on the noise, it indicates that the problem is conducted to
>the radio via the power bus. Tried that from a separate 12V battery - no effect
>
>
snip
Message 4
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| Subject: | strobe whine noise |
Hi Ken
How and where did you insert the filter into the 12V feed to the
strobes? Sounds like you inserted it 'in line' to the strobes.
Its interesting you inserted the filter before the strobes and yet it
reduced the interference in your radio. How do you explain that?
- Frank
________________________________
From: owner-aeroelectric-list-server@matronics.com on behalf of Ken
Sent: Thu 16/08/2007 14:45
Subject: AeroElectric-List: strobe whine noise
FWIW powering my strobes from separate batteries made no difference to
the audio whine that I was hearing from them. Adding some homemade
filter devices likewise had no effect so I guess I did not hit on the
best component values. I never did find a ground issue that I could
blame the problem on. And yet when I finally obtained and tried a cheap
automotive filter on the 12 volt feed to the strobes, the situation
improved markedly and I can no longer hear the strobes in flight. The
directions said to try reversing the filter leads for best effect. Sure
enough the filter only worked well in one direction. Grounding the
ground connection to the filter also had no effect.
Ken
>snip
>Bob often recommends powering from a separate battery the piece(s) of
>equipment that are involved in the problem. A couple of lantern
batteries
>could be used to power the radio while the engine is running.. If that
>has any effect on the noise, it indicates that the problem is conducted
to
>the radio via the power bus. Tried that from a separate 12V battery -
no effect
>
>
snip
Message 5
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| Subject: | strobe whine noise |
When tackling a noise problem, it sometimes makes sense to clean up the
victim, but sometimes it also works to clean up the noise source. In this
case, it sounds like the transient current load presented by the strobes
was causing noise to be added to the audio signal of the comm system
(ground/supply noise). Adding a filter to the strobe circuit likely
reduced the transient load on the bus, decreasing the noise signal seen by
the audio system.
Wiring a power supply filter depends on the components in the filter. If
it is just a choke (coil - inductance), in-line works. If it's a 2nd (or
higher) order filter - has a cap, the filter will need to be both inline
and have a connection to ground.
Regards,
Matt-
> Hi Ken
>
> How and where did you insert the filter into the 12V feed to the strobes?
> Sounds like you inserted it 'in line' to the strobes.
>
> Its interesting you inserted the filter before the strobes and yet it
> reduced the interference in your radio. How do you explain that?
>
> - Frank
>
> ________________________________
>
> From: owner-aeroelectric-list-server@matronics.com on behalf of Ken
> Sent: Thu 16/08/2007 14:45
> To: aeroelectric-list@matronics.com
> Subject: AeroElectric-List: strobe whine noise
>
>
>
> FWIW powering my strobes from separate batteries made no difference to
> the audio whine that I was hearing from them. Adding some homemade
> filter devices likewise had no effect so I guess I did not hit on the
> best component values. I never did find a ground issue that I could
> blame the problem on. And yet when I finally obtained and tried a cheap
> automotive filter on the 12 volt feed to the strobes, the situation
> improved markedly and I can no longer hear the strobes in flight. The
> directions said to try reversing the filter leads for best effect. Sure
> enough the filter only worked well in one direction. Grounding the
> ground connection to the filter also had no effect.
> Ken
>
>>snip
>>Bob often recommends powering from a separate battery the piece(s) of
>>equipment that are involved in the problem. A couple of lantern
>> batteries
>>could be used to power the radio while the engine is running.. If that
>>has any effect on the noise, it indicates that the problem is conducted
>> to
>>the radio via the power bus. Tried that from a separate 12V battery - no
>> effect
>>
>>
> snip
>
>
Message 6
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| Subject: | Off Subject Question |
Sorry about the diversion, but I am certain some of you can solve my
problem.
I have Direct TV and one of my sets uses a UHF remote control. The remote
is used about
30 feet and through 2 block walls from the receiver. It barely works and is
very frustrating.
What can I do to improve the reception of this remote? Is there some
homemade way to increase
The antenna gain?
Thanks for your help!
Bill B
Message 7
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| Subject: | Loss of essential bus |
I have an intermittent loss of the essential bus in my RV-8. I have
wired it similar to Bob's Z-11 Generic Light Aircraft Electrical System
except that I have added an aux battery as depicted in his Z-30
diagram, as I have dual electronic ignition. I suspect that the problem
is in the diode that prevents reverse current when the essential bus
alternate feed switch is turned on. My question: Is it possible that
this diode is defective and could cause intermittent loss of the
essential bus? When it occurs, the current is almost immediately
restored without any action on my part, but it does cause all the
avionics to reboot. It occurs without warning and I cannot trust it in
IFR conditions. Any suggestions? Thanks.
Ron Schreck
RV-8, "Miss Izzy"
Gold Hill Airpark, NC
Message 8
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Is it an acceptable practice to route P-Leads trough the firewall alongside
other power supply cables? I read somewhere (Tony Bingelis Books, I think)
that shielded cables should not run alongside other cables.
Thanks,
Mike Creek
Message 9
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| Subject: | Re: Aeroelectric Connection Book |
At 01:33 PM 8/15/2007 +0800, you wrote:
>
>Hi all
>
>Can anyone confirm if Bob is still active? I ordered his book over a month
>ago and received a confirmation email but have still not received the book
>in the mail. I've sent Bob a chaser via his web page but got no reply...
Sorry for the delay. We were preoccupied with shepherding my
father through his last days and had a long trip to do the
Alaska seminar right on the heals of Dad's funeral. I promise
to chain my self to the order 'puter tomorrow and get 100%
caught up.
Bob . . .
Message 10
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| Subject: | Re: Aeroelectric Connection Book |
I think I can speak for most all others when I say:
Thanks Bob, now stop and take deeeep breath. We all want what we want and
most often we want it right now!
Rest easy fella . What we want from you can wait a day or maybe even
two.....but don't push it eh g-)
Jim in Kelowna
----- Original Message -----
From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
Sent: Thursday, August 16, 2007 6:55 PM
Subject: Re: AeroElectric-List: Aeroelectric Connection Book
> <nuckollsr@cox.net>
>
> At 01:33 PM 8/15/2007 +0800, you wrote:
>
>>
>>Hi all
>>
>>Can anyone confirm if Bob is still active? I ordered his book over a month
>>ago and received a confirmation email but have still not received the book
>>in the mail. I've sent Bob a chaser via his web page but got no reply...
>
> Sorry for the delay. We were preoccupied with shepherding my
> father through his last days and had a long trip to do the
> Alaska seminar right on the heals of Dad's funeral. I promise
> to chain my self to the order 'puter tomorrow and get 100%
> caught up.
>
> Bob . . .
>
>
>
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