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1. 08:41 AM - Re: Re: Request for some direction and advise (Robert L. Nuckolls, III)
2. 06:52 PM - Re: Re: Request for some direction and advise (Bill Bradburry)
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Subject: | RE: Request for some direction and advise |
At 10:15 PM 8/30/2015, you wrote:
>I saw where someone else on the list a while back was discussing
>adding that connector to their TruTrak at the company's
>suggestion. It is supposed to keep RFI out as I recall.
>
>The antenna is glassed in and not removable, I tried to attach it
>with tape, but I could not get it to stay in place so I just glassed
>it in. I do have a second antenna that I could try if I don't find
>anything with the coax. I only have a Volt-Ohm meter so I don't
>think I could bench test the antenna.
>
I feel your 'pain' . . . more than once
I have been presented with a conundrum
with tools and test equipment out of reach.
Do the touchy-feely things with the
feed line first. Then consider building
a test antenna. A simple dipole, fed at
center with a length of coax fited with
BNC cable-female to reach across the
aircraft to the opposite side where
you can tape it in place.
See if the problem resolves.
I don't know any specifics about the antenna
you have installed. I have been made aware
of several products like it wherein the
manufacturer thought it a good idea to
include a balun/matching transformer in
that little potted box at the center.
On such product could not handle the
power from the transmitter and failed
the balun after some hours in service.
We're grasping at straws here but one
of those straws IS the short one. Without
useful diagnostic tools . . . it's
the best we can do.
But if it's any consolation, I've encountered
ONLY ONE EMC problem on an airplane wherein
root cause could NOT be resolved . . . only
swapped out.
Emacs!
Seems that some really nifty technology advances
in communications hardware were installed
on an aircraft being manufactured to still
adequate methods designed 40 years ago.
A technology that placed NEW and exceedingly
difficult requirements on the airframe.
From that time to this day, the aircraft has
suffered a host of EMC problems that occur
at intervals, sometimes in small batches,
and will never be resolved except that the
old wire-type antennas be re-installed.
I'm not suggesting that your situation is
intractable . . . only that not all combinations
of hardware are plug-n-play in all airframes
and yours is fixable.
Only spent a few hundred $K tracking the
other one down . . . yours will be MUCH
less expensive.
Bob . . .
Message 2
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Subject: | RE: Request for some direction and advise |
I checked the connectors at the two ends of the com coax. They were
both
well connected to the shield and I couldn't pull them off the cable.
The, I
guess you would call it the barrel, of the connector at the radio end
was a
little difficult to twist after the connector was removed. I twisted it
back and forth a little and it seemed to loosen up. I suppose there
could
have been some corrosion where it rotates, but I didn't see anything.
I checked and found the radio backing plate had continuity with ground.
There is a card edge connector that is used as a shield ground connector
at
the backing plate that seemed to me to be a loose fit. I mean it was
easy
to remove it from the plate it connects to. It is held in place by a
couple
of screws so there was no danger of it falling off, but it was a loose
fit
so I suppose that some of the pins could have not been making good
contact.
I don't know if any of the shields that are in this connector could have
caused the problem.
I wonder if I should try and bend the pins so that they make a tighter
fit?
Also should the edge it slips over be brightened up some? It is the
same
grey color as the backing plate?
I found another RG-400 cable with connectors on both ends that I could
use
to hook up the other antenna I have to see if that helps. I don't know
if
the spare cable will reach to the existing antenna. If it does I could
try
that as well.
Bill
_____
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
Robert L.
Nuckolls, III
Sent: Monday, August 31, 2015 10:40 AM
Subject: RE: AeroElectric-List: RE: Request for some direction and
advise
At 10:15 PM 8/30/2015, you wrote:
I saw where someone else on the list a while back was discussing adding
that
connector to their TruTrak at the company=12s suggestion. It is
supposed to
keep RFI out as I recall.
The antenna is glassed in and not removable, I tried to attach it with
tape,
but I could not get it to stay in place so I just glassed it in. I do
have
a second antenna that I could try if I don=12t find anything with the
coax. I
only have a Volt-Ohm meter so I don=12t think I could bench test the
antenna.
I feel your 'pain' . . . more than once
I have been presented with a conundrum
with tools and test equipment out of reach.
Do the touchy-feely things with the
feed line first. Then consider building
a test antenna. A simple dipole, fed at
center with a length of coax fited with
BNC cable-female to reach across the
aircraft to the opposite side where
you can tape it in place.
See if the problem resolves.
I don't know any specifics about the antenna
you have installed. I have been made aware
of several products like it wherein the
manufacturer thought it a good idea to
include a balun/matching transformer in
that little potted box at the center.
On such product could not handle the
power from the transmitter and failed
the balun after some hours in service.
We're grasping at straws here but one
of those straws IS the short one. Without
useful diagnostic tools . . . it's
the best we can do.
But if it's any consolation, I've encountered
ONLY ONE EMC problem on an airplane wherein
root cause could NOT be resolved . . . only
swapped out.
Emacs!
Seems that some really nifty technology advances
in communications hardware were installed
on an aircraft being manufactured to still
adequate methods designed 40 years ago.
A technology that placed NEW and exceedingly
difficult requirements on the airframe.
From that time to this day, the aircraft has
suffered a host of EMC problems that occur
at intervals, sometimes in small batches,
and will never be resolved except that the
old wire-type antennas be re-installed.
I'm not suggesting that your situation is
intractable . . . only that not all combinations
of hardware are plug-n-play in all airframes
and yours is fixable.
Only spent a few hundred $K tracking the
other one down . . . yours will be MUCH
less expensive.
Bob . . .
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