Today's Message Index:
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1. 08:51 AM - Re: strobe whine noise (Miskelly, Francis G)
2. 08:03 PM - Re: Headset plug polarity (Charlie England)
Message 1
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| Subject: | strobe whine noise |
Many thanks for the explanation Matt
- Frank
________________________________
From: owner-aeroelectric-list-server@matronics.com on behalf of Matt
Prather
Sent: Thu 16/08/2007 17:23
Subject: RE: AeroElectric-List: strobe whine noise
<mprather@spro.net>
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 2
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| Subject: | Re: Headset plug polarity |
Bill Bradburry wrote:
>
> I am amazed at the difficulty in finding the polarity on the internet. Can
> someone help me here?
>
> What should be the polarity of the sleeve, ring, and tip on a stereo plug?
> Which, ring or tip, is probably right and which is probably left on the
> stereo plug?
>
> Also what should be the polarity of the sleeve and tip on the mono plug.
>
> How should I wire a stereo receptacle so that it could be used for both
> stereo or mono?
>
> Thanks,
> Bill B
Hi Bill,
I think that my email messages have been wandering around in Ted
Stevens' "pipes" for days before being delivered to me.
There's a simple way to check right/left wiring in a connector. Grab a 1
1/2V battery, a couple of clip leads & your stereo headset. Put the
headset on your head, but offset the earcups so they aren't over your
ears. Connect one terminal from the battery to the sleeve (closest to
the insulated end & wire). Touch the other terminal of the battery to
the tip of the connector. The side that clicks as you make & break the
connection is wired to the tip. Assuming that you are wearing the
headset correctly, you now know how the connector should be wired. To
get the right terminal on the jack, just remember that the tip is
farthest from the nut and follow the metal to the solder tab. Same
principle for ring & sleeve in the jack.
There isn't really any practical way to wire a stereo connector for both
stereo & mono. You can set it up with a switch, but then you're
dependent on remembering to set the switch correctly.
Charlie
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