Today's Message Index:
----------------------
1. 05:29 AM - Re: RF interference on GRT fuel pressure with PTTRF interference on GRT fuel pressure with PTT (Fred Stucklen)
2. 10:01 AM - Re: RF interference on GRT fuel pressure (Robert L. Nuckolls, III)
3. 10:11 AM - Re: Switches all upside-down... (Robert L. Nuckolls, III)
4. 12:30 PM - Re: Re: RF interference on GRT fuel pressure (Tim Andres)
5. 10:10 PM - Load Analysis Feedback Please... (idleup)
Message 1
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| Subject: | Re: RF interference on GRT fuel pressure with PTTRF |
interference on GRT fuel pressure with PTT
Tim,
I ordered four units (Their evaluation kit), so will start out by trying
just the sensor DB. If that doesn't solve the problem, I'll add one to the
TEMP sensor DB input. My fear is that the actual sensor (I have the high
pressure precision unit for a fuel injected engine) is being effected by the
RFI. If this is the case, the signal coming from the sensor would be bad,
causing the EFIS alarms. This type of problem can only be solved by
protecting the sensor with capacitors.
The EMC units have male pins on one side, female on the other side,
allowing them to be put in-line with the existing cable connectors.
Fred Stucklen
Time:
02:45:41 PM PST US
Subject:
Re: RF interference on GRT fuel pressure with PTTRF
interference on GRT fuel pressure with PTT
From:
Tim Andres <tim2542@sbcglobal.net>
Thanks Fred, I had not gotten around to ordering yet as I recall one
DB was m
ale pin and the other female. Do you plan to put one on each connector
or ju
st the one that has the fuel pres. sensor?
Tim
Sent from my iPad
On Dec 27, 2012, at 11:35 AM, "Fred Stucklen" <wstucklen1@cox.net>
wrote:
> I just put in an order for their evaluation kit for four DB25 EMC
units (I
tem # 903C). I=99ve been having problems with RFI getting into the fue
l pressure circuit, causing fuel pressure warnings on the EFIS engine
page. I
=99ll put this unit onto the DB-25 on the EIS and see if it solves the
issue (or makes it worst). It can=99t hurt, but may not eliminate the
issue is RFI getting into the fuel pressure sending unit, causing it
to sen
d the wrong information. Only a cap across it=99s leads would then eli
minate the problem..
>
> Fred Stucklen
> RV-7A N924RV 800+ Hrs
> Triple GRT EFIS
> GRT EIS
>
>
> Time:
> 02:23:24 PM PST US
> From:
> Tim Andres <tim2542@sbcglobal.net>
> Subject:
> Re: RF interference on GRT fuel pressure with PTT
>
> Wow cool idea. I=99ll be the guinea pig and report back when i
t=99s see if it fixes
> the problem.
> Tim
>
>
> ________________________________
> From: ChangDriver <capav8r@gmail.com>
> Sent: Wed, December 26, 2012 2:19:18 PM
> Subject: AeroElectric-List: Re: RF interference on GRT fuel
pressure
with PTT
>
>
> Forget about trying to put the capacitor on the line and
solder to g
round and
> just get one of these noise supression connector adapters.
>
> http://www.camiresearch.com/connector_protector.html
>
> Way simpler and it puts EMI supression on each pin!
>
Message 2
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| Subject: | Re: RF interference on GRT fuel pressure |
At 07:28 AM 12/28/2012, you wrote:
>Tim,
>
> I ordered four units (Their evaluation kit), so will start out by
> trying just the sensor DB. If that doesn't solve the problem, I'll
> add one to the TEMP sensor DB input. My fear is that the actual
> sensor (I have the high pressure precision unit for a fuel injected
> engine) is being effected by the RFI. If this is the case, the
> signal coming from the sensor would be bad, causing the EFIS
> alarms. This type of problem can only be solved by protecting the
> sensor with capacitors.
I'm sorry to have been out of the loop on this.
Extended family holiday activities (still going
on) plus a run-in with the flu (grandkids attending
a constellation of schools are veritable dragnets
for viruses) has kept Dr. Dee and myself somewhat,
uh . . indisposed.
Is this a new, untried combination of hardware?
Is the problem common to other identical installations
or just with your airplane?
The great RFI/Filter/Ferrite/copper-box hat-dance
to mitigate an RFI issue may have more to do with
conditions outside the affected system.
Bring me up to date on what's happening, what you've
tried, etc.
Bob . . .
Message 3
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| Subject: | Re: Switches all upside-down... |
At 12:56 PM 12/27/2012, you wrote:
>Lynn,
>I used the =98thin .035-.065=99 strip behind my
>switches to allow the tabs to go in the correct
>place for switch orientation. As long as you
>have two or more switches side by side, you can
>avoid rotation. Easier than drilling into the panel itself
>
>Bill Schertz
Yes. We had this very same discussion some years
back. I think I did a short article suggesting that
a 'drill fixture' be fabricated from a strip of
aluminum that featured #40 drilled centers for
switches and washer tabs. Then use the fixture to
match drill a set of pilot holes in the panel.
Drill out all holes to final size and then use
the 'fixture' on the back side to secure the
locking tabs. It could be assembled with tabs
up or down.
The only toggle switches that are really upside
down are the un-symmetrical devices. I.e., Single
throw or spring loaded to one side. This is why
I only stocked the S700-2-3 switch for single throw
service, it could be wired to function right side up
with the locking tab in either position. The only
time you risk getting 'hosed' is with switches having
spring loading from one side to center. In any case,
making a drill template on the bench assures tighter
location for holes to centers.
Having a tight-tolerance template makes the job
in the airplane go much faster, with greater precision
and accommodates locking tabs without having to
drill the instrument panel.
At one time, I considered offering aluminum strips about
1-1/2" wide center-drilled on a mill to locate the two rows
of holes with great precision. I might still do that.
Bob . . .
Message 4
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| Subject: | Re: RF interference on GRT fuel pressure |
Hi Bob and thanks!
The issue is fuel pressure spikes on transmit with the GRT EIS system. At le
ast 3 cases I know of. On mine it only occurs at the higher end of the band u
sing either comm.
GRT suggested a split ferrite over the bundle just before it enters the DB 2
5 connector, I have not tried anything yet myself but plan to during my cond
ition inspection.
These look like a slick way to do what you had suggested earlier, that is sm
all caps between the pins and ground. My only concern is I know there are bo
th gender DB 25 connectors on the back of the unit and I need to determine i
f they sell both and or which one I need.
Tim
Sent from my iPad
On Dec 28, 2012, at 10:00 AM, "Robert L. Nuckolls, III" <nuckolls.bob@aeroel
ectric.com> wrote:
> At 07:28 AM 12/28/2012, you wrote:
>> Tim,
>>
>> I ordered four units (Their evaluation kit), so will start out by tryin
g just the sensor DB. If that doesn=99t solve the problem, I=99l
l add one to the TEMP sensor DB input. My fear is that the actual sensor (I h
ave the high pressure precision unit for a fuel injected engine) is being ef
fected by the RFI. If this is the case, the signal coming from the sensor wo
uld be bad, causing the EFIS alarms. This type of problem can only be solved
by protecting the sensor with capacitors.
>
> I'm sorry to have been out of the loop on this.
> Extended family holiday activities (still going
> on) plus a run-in with the flu (grandkids attending
> a constellation of schools are veritable dragnets
> for viruses) has kept Dr. Dee and myself somewhat,
> uh . . indisposed.
>
> Is this a new, untried combination of hardware?
> Is the problem common to other identical installations
> or just with your airplane?
>
> The great RFI/Filter/Ferrite/copper-box hat-dance
> to mitigate an RFI issue may have more to do with
> conditions outside the affected system.
>
> Bring me up to date on what's happening, what you've
> tried, etc.
>
>
> Bob . . .
>
>
>
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>
Message 5
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| Subject: | Load Analysis Feedback Please... |
Would you guys be so kind as to review my Load Analysis worksheet and tell me if
you see anything that looks incorrect or have recommendations to make it better?
I have spent quite a bit of time on this but at the end of the day still
question whether I know what I am doing and would appreciate some peer review...
Thanks.
Of if you would prefer to download the PDF: http://www.mattandmel.com/rv/Master_Load_Analysis_v1.pdf
Thank you much.
Matt
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http://forums.matronics.com/viewtopic.php?p=391129#391129
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