 |
Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
|
| View previous topic :: View next topic |
| Author |
Message |
jpx(at)Qenesis.com
Guest
|
 Posted: Thu Dec 13, 2007 6:11 pm Post subject: Antenna Grounding |
 |
|
Today I received my Comant CI-121 VHF Com antennas. They did not
include any installation instructions. There is some generic
installation instructions on their web site at:
http://www.comant.com/htmls/guide1.html
This indicates that the electical bonding to the aircraft ground is
important and can be accomplished by ensuring good metal-metal contact
with the aluminum skin, or with the mounting screws attaching to a
backing plate (not provided).
Included with the antenna is a cork gasket that will eliminate any
metal-metal contact. The screws appear to connect only with a
fiberglass outer shell. So there will be no ground connection except
through the coax cable.
How should this antenna really be installed on an aluminum aircraft ?
Jeff Page
Dream Aircraft Tundra #10
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
| Back to top |
|
 |
nuckolls.bob(at)cox.net
Guest
|
| Posted: Thu Dec 13, 2007 7:11 pm Post subject: Antenna Grounding |
|
|
At 09:09 PM 12/13/2007 -0500, you wrote:
| Quote: |
Today I received my Comant CI-121 VHF Com antennas. They did not
include any installation instructions. There is some generic
installation instructions on their web site at:
http://www.comant.com/htmls/guide1.html
This indicates that the electical bonding to the aircraft ground is
important and can be accomplished by ensuring good metal-metal contact
with the aluminum skin, or with the mounting screws attaching to a
backing plate (not provided).
Included with the antenna is a cork gasket that will eliminate any
metal-metal contact. The screws appear to connect only with a
fiberglass outer shell. So there will be no ground connection except
through the coax cable.
How should this antenna really be installed on an aluminum aircraft ?
|
Pitch the gasket. Don't scrape your paint except in immediate
vicinity of mounting holes. These areas are marked (*) in
http://www.aeroelectric.com/Pictures/Antenna/Antenna_Installation.gif
where you will take advantage of the clamp-up forces on
the mounting bolts. Sealing can be accomplished with a filet
of RTV around the finished installation.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
| Back to top |
|
|
lamphere(at)vabb.com
Guest
|
| Posted: Fri Dec 14, 2007 6:09 am Post subject: Antenna Grounding |
|
|
I'm curious ...
if the body of the antenna in question is non-conductive, what difference
does it make to use the gasket or not? Wouldn't the grounding of the
outside/shield of the bnc connector be the important connection (if there is
to be one) with respect to mounting?? And how would that be established??
Thanking you in advance for your experienced technical response,
Dave L.
---
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
| Back to top |
|
|
nuckolls.bob(at)cox.net
Guest
|
| Posted: Sat Dec 15, 2007 11:53 am Post subject: Antenna Grounding |
|
|
At 09:10 AM 12/14/2007 -0500, you wrote:
| Quote: |
<lamphere(at)vabb.com>
I'm curious ...
if the body of the antenna in question is non-conductive, what difference
does it make to use the gasket or not? Wouldn't the grounding of the
outside/shield of the bnc connector be the important connection (if there
is to be one) with respect to mounting?? And how would that be established??
Thanking you in advance for your experienced technical response,
|
The outer shield of the coax wants to
become well connected to the aircraft skin.
This happens by virtue of good connections to
the outside shell of a BNC connector on the
coax which makes good connection with the
connector on the antenna's base plate which
in turn should be well connected to the skin.
This is why the areas marked (*) in photo cited
are critical both with respect to cleanliness
to bare metal but also clamp-up forces for the
purpose of attaining gas-tight joints.
Bob . . .
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
| Back to top |
|
|
BobsV35B(at)aol.com
Guest
|
| Posted: Sat Dec 15, 2007 12:04 pm Post subject: Antenna Grounding |
|
|
Good Afternoon Bob,
I have seen references that suggested using Alodine 1001 or 1003 on the areas that have been cleaned.
Any comment?
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Air Park LL22
Downers Grove, IL 60516
630 985-8503
In a message dated 12/15/2007 1:55:52 P.M. Central Standard Time, nuckolls.bob(at)cox.net writes:
| Quote: | The outer shield of the coax wants to
become well connected to the aircraft skin.
This happens by virtue of good connections to
the outside shell of a BNC connector on the
coax which makes good connection with the
connector on the antenna's base plate which
in turn should be well connected to the skin.
This is why the areas marked (*) in photo cited
are critical both with respect to cleanliness
to bare metal but also clamp-up forces for the
purpose of attaining gas-tight joints.
Bob . . .
|
See AOL's top rated recipes and easy ways to stay in shape for winter.
[quote][b]
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
| Back to top |
|
|
nuckolls.bob(at)cox.net
Guest
|
| Posted: Sat Dec 15, 2007 12:43 pm Post subject: Antenna Grounding |
|
|
At 03:02 PM 12/15/2007 -0500, you wrote:
| Quote: | Good Afternoon Bob,
I have seen references that suggested using Alodine 1001 or 1003 on the
areas that have been cleaned.
Any comment?
|
Yeah, one can probably demonstrate a modicum of
"protection" for such chemically induced films.
Bottom line is that these ARE chemically induced
layers that are exceedingly thin. If one's airplane
is billeted in a salt-air or high humidity environment,
then the improvement for having taken prophylactic
measures such as brushed on films is difficult
to demonstrate.
Actually, a silicone grease is probably a better
bet. The compression strength of the grease is on
the order of .001 PSI while clamp-up forces in
the joint will me thousands of PSI. Any grease
in a potential metal-to-metal joint will be
extruded out . . . while voids in the finished
joint will still be filled with the grease.
I'd stand Dow Corning DC-4 up against Alodine
chem films in a heartbeat. On the other hand,
two surfaces clamped together in a gas-tight
bond, then NO additional corrosion proofing is
necessary or useful.
Bob . . .
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
| Back to top |
|
|
jpx(at)Qenesis.com
Guest
|
| Posted: Sat Dec 15, 2007 6:39 pm Post subject: Antenna Grounding |
|
|
Actually the bottom of the base is plated steel. The visible part of
the base, holding the antenna seems to be fiberglass. So the heads of
the screws hold onto fiberglass. The steel bottom of the antenna will
be touching the aluminum skin provided I do not install the cork
gasket. The BNC connector is on the bottom of course.
Jeff Page
| Quote: | Time: 06:09:12 AM PST US
From: "David & Elaine Lamphere" <lamphere(at)vabb.com>
Subject: Re: Antenna Grounding
I'm curious ...
if the body of the antenna in question is non-conductive, what difference
does it make to use the gasket or not? Wouldn't the grounding of the
outside/shield of the bnc connector be the important connection (if there is
to be one) with respect to mounting?? And how would that be established??
Thanking you in advance for your experienced technical response,
Dave L.
|
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
