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Try one of the Pin-to-Socket Adapters FCC17 series in the attachment.
Worked for me.
Steve
-----Original Message-----
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of John
Schroeder
Sent: Sunday, December 10, 2006 11:31 AM
To: lml
Subject: [LML] Re: Observed Comm Mic Interference with JPI and TITs
Jeff -
We are having the same troubles with RF feeding into the Blue Mountain
engine instruments and into the Tru Trak DFC-250. One of the antennas, the
most egregious, is on the right wall of the aft part of the baggage
compartment. It is a Bob Archer "E" shaped com antenna. Bob feels that
pretty high levels of RF is getting into the two DC power circuits, probably
from the battery feed cables that are routed below the antenna in the bottom
of the fuselage. His suggestion is to install 50 pico farad capacitors
between positive & grnd leads on these two DC circuits on the firewall -
before the DC buss feeds.
Another suggestion from a couple of HAM gurus is to install toroid
suppressors on all of the cabling feeding power instrument signals into the
EFIS.
I'll try to get some from JPI. The interesting thing is that the JPI EDM has
absolutely no reaction to this problem.
Keep us posted on what works for you. I can't imagine getting the same
reaction with the radios and audio panel off. Emissions from the
alternator/s?
Cheers,
John
On Sun, 10 Dec 2006 13:39:24 -0500, Jeffrey Liegner, MD
<liegner@earthlink.net> wrote:
> I have a comm bug that needs some ideas on cause and solve.
>
> Toggling mic button (transmit) on the joystick causes the displayed
> TIT2 and (to a lesser extent) TIT1 values (on EAU/Chelton) to promptly
> increase and the separate JPI ammeter/voltmeter readings to go screwy.
>
> I plan to place a JPI provided feritte suppressor between each of the
> two bussses and the JPI Shunts.
>
> Interestingly, in addition to when actually transmitting on the comm,
> this observed screwy change occurs when all comm units are OFF and
> their circuit breakers are pulled, and even when the PMA7000B intercom
> is also off with its CB pulled. Note that the observed effect is the
> same when everything is OFF or ON, when the mic button is toggled.
>
> It happens on both joysticks, but appears more pronounced with the
> pilot side mic compared to the copilot side mic button.
>
> Any wisdom on this ghost?
>
> Jeff L
>
> --
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>
>
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