Today's Message Index:
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1. 10:21 AM - RF interference fix? (Erich_Weaver@URSCorp.com)
2. 07:14 PM - Re: Cessna 150F Landing/Taxi light switch. (Robert L. Nuckolls, III)
Message 1
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| Subject: | RF interference fix? |
>From first flight, the GRT EFIS and EIS on my RV have indicated momenta
ry,
anomalously high fuel pressure readings, typically just before take-off
and
also when entering and in the pattern. Stewed over that for over a yea
r
before asking myself the question - how does the system KNOW Im going t
o
takeoff or land? Asking that question led me to the only possible answ
er:
it knows because I get on comm and announce it! A couple of weeks ago I
confirmed this - every comm transmission resulted in a sharp rise in fu
el
pressure. Yesterday I took it a step further, seeking to determine wha
t
the propogation mode was, and reasoned it was either RF interference or
some sort of magnetic coupling associated with the increased power
requirements during comm transmissions. The easy test was to get out m
y
battery operated handheld transceiver and transmit from inside the cock
pit
with the engine running and the EFIS/EIS powered up, so I did that firs
t.
Bingo - a similar increase in the fuel pressure reading, although to a
lesser degree than with ship's comm. Also noticed a lot of noise on my
handheld when receiving from inside the cockpit - noise that isnt
noticeable on ship's comm, nor on the handheld normally.So, now Im feel
ing
pretty high and mighty with my diagnostic skills, but the problem still
remains - where do I go from here to fix this?
thanks
erich
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Message 2
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| Subject: | Re: Cessna 150F Landing/Taxi light switch. |
At 06:24 PM 6/6/2009, you wrote:
>I have a very basic question. The switch in question burnt out so I
>obtained a replacement. For the life of me I can't figure out which
>wire goes where. I have three wires, power and feeds to the Landing
>and Taxi lights. The switch has four connectors marked H,R,A,
>B. The case is marked 600 and is a pull switch with two positions.
>Can anyone help? I am aware it is not RV related. When I'm not
>flying my RV4 I have the Cessna to take pictures etc.
>SSD
It has been a VERY long time since I've seen these
switches installed on the Cessnas but if it's a
4-terminal switch I suspect that an ohmmeter test
will show that with the switch has no connections
with the handle all the way in.
With the handle pulled to the first notch, I think
the pair of terminals furthest from the panel will
be connected to each other. This pair is the taxi
light circuit. With the handle all the way out, the
pair of terminals closest to the panel will be connected
to turn on the landing light. In this position, the
taxi light will be out. Here's an exemplar 4-terminal
push-pull switch from Cole-Hersee
Emacs!
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
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