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noah(at)acsalaska.net Guest
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Posted: Thu Apr 05, 2012 8:02 am Post subject: ELT antenna location RV8A |
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I am replacing the old 121.5 ELT with a 406 in my RV8A. The old antenna was under the empennage fairing. The new antenna is longer and doesn’t fit as good in that location and I am thinking there might be a better location. With the sliding canopy I am scratching my head. Where are others putting their antenna? Thanks Rollin
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crowbotham(at)hotmail.com Guest
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Posted: Fri Apr 06, 2012 4:12 am Post subject: ELT antenna location RV8A |
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Hi Rollin,
We placed our old 121.5 antenna on the right rear seat bulkhead ( just off the rear passenger's Right shoulder ) and secured the antenna as the tip bent around the top of the bulkhead. Always tested well and never had a problem with canopy slider or the rear seat vertical panel. Our ELT transmitter was located under the baggage shelf.
Chuck & Dave Rowbotham
RV-8A sold
From: noah(at)acsalaska.net
To: rv8-list(at)matronics.com; rv-list(at)matronics.com
Subject: ELT antenna location RV8A
Date: Thu, 5 Apr 2012 08:00:20 -0800
I am replacing the old 121.5 ELT with a 406 in my RV8A. The old antenna was under the empennage fairing. The new antenna is longer and doesn’t fit as good in that location and I am thinking there might be a better location. With the sliding canopy I am scratching my head. Where are others putting their antenna? Thanks Rollin
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get=_blank>http://www.matronics.com/Navigator?RV-List
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jhclarkfl
Joined: 17 Jan 2009 Posts: 9 Location: Pensacola, FL
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Matt Dralle Site Admin
Joined: 08 Nov 2005 Posts: 26320 Location: Livermore CA USA
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Posted: Fri Apr 06, 2012 5:22 pm Post subject: ELT antenna location RV8A |
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At 09:00 AM 4/5/2012 Thursday, you wrote:
Quote: | I am replacing the old 121.5 ELT with a 406 in my RV8A. The old antenna was under the empennage fairing. The new antenna is longer and doesn’t fit as good in that location and I am thinking there might be a better location. With the sliding canopy I am scratching my head. Where are others putting their antenna? Thanks Rollin
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I have the Ameri-King AK-451 ELT with GPS input on the RV-8 and mounted my antenna under the fin. Seem to fit well. Attached is a picture.
-
Matt Dralle
RV-8 #82880 N998RV "Ruby Vixen"
http://www.mattsrv8.com - Matt's Complete RV-8 Construction Log
http://www.mattsrv8.com/Mishap - Landing Mishap Rebuild Log
http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel
Status: 172+ Hours TTSN - Rebuilding Fuselage After Landing Mishap...
RV-6 #20916 N360EM "The Flyer"
http://www.mattsrv6.com - Matt's RV-6 Revitalization Log
Status: 870+ Hours Since Purchase - Upgrades Complete; Now In Full Flyer Mode
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Hopperdhh(at)aol.com Guest
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Posted: Mon Apr 16, 2012 5:06 am Post subject: ELT antenna location RV8A |
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I can't believe a DAR would OK these internal ELT antenna installations! No matter what an antenna analyzer says, these things can't possibly radiate much beyond about maybe 100 ft. I'm talking about antennas under the empennage fairing, and mounted so the whole length is near the metal structure of the airplane.
No one wants to put the ELT antenna outside and create drag, but that's where it should be. I couldn't find in the manual for my AK-50 where it warns against this type of installation, except it says "External Antenna." I'm sure they are talking about external to the airplane.
We all want our COM antenna to radiate well, so most of them are mounted external to the airplane. An ELT is a waste of money with the antenna mounted like so many are.
I wish some knowledgeable person with the right equipment would make some field strength measurements on these installations vs. some with the antenna mounted external to the airplane. If the results are comparable, I'll gladly eat my words.
I'm sure this won't be a very popular post, but it needed to be said.
Dan Hopper
RV-7A
Flying since 2004
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Hopperdhh(at)aol.com Guest
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Posted: Mon Apr 16, 2012 5:09 am Post subject: ELT antenna location RV8A |
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I meant to say AK-450.
In a message dated 4/16/2012 9:07:11 A.M. Eastern Daylight Time, Hopperdhh(at)aol.com writes:
Quote: |
I can't believe a DAR would OK these internal ELT antenna installations! No matter what an antenna analyzer says, these things can't possibly radiate much beyond about maybe 100 ft. I'm talking about antennas under the empennage fairing, and mounted so the whole length is near the metal structure of the airplane.
No one wants to put the ELT antenna outside and create drag, but that's where it should be. I couldn't find in the manual for my AK-50 where it warns against this type of installation, except it says "External Antenna." I'm sure they are talking about external to the airplane.
We all want our COM antenna to radiate well, so most of them are mounted external to the airplane. An ELT is a waste of money with the antenna mounted like so many are.
I wish some knowledgeable person with the right equipment would make some field strength measurements on these installations vs. some with the antenna mounted external to the airplane. If the results are comparable, I'll gladly eat my words.
I'm sure this won't be a very popular post, but it needed to be said.
Dan Hopper
RV-7A
Flying since 2004
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[quote][b]
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Kellym
Joined: 10 Jan 2006 Posts: 1705 Location: Sun Lakes AZ
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Posted: Mon Apr 16, 2012 6:11 am Post subject: ELT antenna location RV8A |
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Well, your assumptions may not be entirely correct. The late model
Mooneys have a certified 406 antenna installation under the fiberglass
fairing in front of vertical stabilizer (mostly horizontal
orientation). They were able to get it to pass whatever tests were
required. As for range, I've had my antique ELT-10 go off while the
plane was in my hangar, and it was picked up by satellite. Yes,
surrounded by 4 metal walls and roof. Given the extra power of 406
transmitters, I doubt it is much of an issue. Remember what most DAR's
focus on...obvious flight safety issues and paperwork. I don't think ELT
is going to register much in their mind beyond the fact that one is present.
Kelly
On 4/16/2012 6:04 AM, Hopperdhh(at)aol.com wrote:
Quote: | I can't believe a DAR would OK these internal ELT antenna
installations! No matter what an antenna analyzer says, these things
can't possibly radiate much beyond about maybe 100 ft. I'm talking
about antennas under the empennage fairing, and mounted so the whole
length is near the metal structure of the airplane.
No one wants to put the ELT antenna outside and create drag, but
that's where it should be. I couldn't find in the manual for my AK-50
where it warns against this type of installation, except it says
"External Antenna." I'm sure they are talking about external to the
airplane.
We all want our COM antenna to radiate well, so most of them are
mounted external to the airplane. An ELT is a waste of money with the
antenna mounted like so many are.
I wish some knowledgeable person with the right equipment would make
some field strength measurements on these installations vs. some with
the antenna mounted external to the airplane. If the results are
comparable, I'll gladly eat my words.
I'm sure this won't be a very popular post, but it needed to be said.
Dan Hopper
RV-7A
Flying since 2004
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_________________ Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD |
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carl.froehlich(at)verizon Guest
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Posted: Mon Apr 16, 2012 6:41 am Post subject: ELT antenna location RV8A |
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You have a point, but...
I believe the best place to mount the ELT antenna in under the Empennage fairing. I fully acknowledge that the antenna's performance will be less than the same antenna mounted on top (or bottom) of the fuselage, clear of all obstacles.
So now overlay why we have this antenna. We do not care much about how well it performs with the airplane parked on the ramp. We wish it to work in any configuration we may find ourselves in a hard, off field landing. Every photo I've seen of airplane crashes tells me the most survivable portion of the plane is the intersection of the horizontal and vertical stabilizer. If you mount your antenna in a less survivable place, how well it performs before the crash makes little difference if the airplane is on top of it.
Most RV's I've seen have the ELT antenna mounted as I suggest. I tested mine and it appeared to work as well as others that were mounted on top of the fuselage. This test was just a single data point in an uncontrolled environment.
Carl
On Apr 16, 2012, at 9:08 AM, Hopperdhh(at)aol.com (Hopperdhh(at)aol.com) wrote:
[quote] I meant to say AK-450.
In a message dated 4/16/2012 9:07:11 A.M. Eastern Daylight Time, Hopperdhh(at)aol.com (Hopperdhh(at)aol.com) writes:
Quote: |
I can't believe a DAR would OK these internal ELT antenna installations! No matter what an antenna analyzer says, these things can't possibly radiate much beyond about maybe 100 ft. I'm talking about antennas under the empennage fairing, and mounted so the whole length is near the metal structure of the airplane
No one wants to put the ELT antenna outside and create drag, but that's where it should be. I couldn't find in the manual for my AK-50 where it warns against this type of installation, except it says "External Antenna." I'm sure they are talking about external to the airplane.
We all want our COM antenna to radiate well, so most of them are mounted external to the airplane. An ELT is a waste of money with the antenna mounted like so many are.
I wish some knowledgeable person with the right equipment would make some field strength measurements on these installations vs. some with the antenna mounted external to the airplane. If the results are comparable, I'll gladly eat my words.
I'm sure this won't be a very popular post, but it needed to be said.
Dan Hopper
RV-7A
Flying since 2004
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Kellym
Joined: 10 Jan 2006 Posts: 1705 Location: Sun Lakes AZ
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Posted: Mon Apr 16, 2012 7:02 am Post subject: ELT antenna location RV8A |
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Excellent points. Also, you want antenna perpendicular to the direction
of the receiving antenna. Well, look at the direction of a satellite.
In many off airport/field landings the airframe winds up either nose
low/tail high, or upside down. Unless vertical stab protects the
antenna, many will get broken.
On 4/16/2012 7:41 AM, Carl Froehlich wrote:
Quote: | You have a point, but...
I believe the best place to mount the ELT antenna in under the
Empennage fairing. I fully acknowledge that the antenna's performance
will be less than the same antenna mounted on top (or bottom) of the
fuselage, clear of all obstacles.
So now overlay why we have this antenna. We do not care much about
how well it performs with the airplane parked on the ramp. We wish it
to work in any configuration we may find ourselves in a hard, off
field landing. Every photo I've seen of airplane crashes tells me the
most survivable portion of the plane is the intersection of the
horizontal and vertical stabilizer. If you mount your antenna in a
less survivable place, how well it performs before the crash makes
little difference if the airplane is on top of it.
Most RV's I've seen have the ELT antenna mounted as I suggest. I
tested mine and it appeared to work as well as others that were
mounted on top of the fuselage. This test was just a single data
point in an uncontrolled environment.
Carl
On Apr 16, 2012, at 9:08 AM, Hopperdhh(at)aol.com
<mailto:Hopperdhh(at)aol.com> wrote:
> I meant to say AK-450.
> In a message dated 4/16/2012 9:07:11 A.M. Eastern Daylight Time,
> Hopperdhh(at)aol.com <mailto:Hopperdhh(at)aol.com> writes:
>
> I can't believe a DAR would OK these internal ELT antenna
> installations! No matter what an antenna analyzer says, these
> things can't possibly radiate much beyond about maybe 100 ft.
> I'm talking about antennas under the empennage fairing, and
> mounted so the whole length is near the metal structure of the
> airplane
> No one wants to put the ELT antenna outside and create drag, but
> that's where it should be. I couldn't find in the manual for my
> AK-50 where it warns against this type of installation, except it
> says "External Antenna." I'm sure they are talking about
> external to the airplane.
> We all want our COM antenna to radiate well, so most of them are
> mounted external to the airplane. An ELT is a waste of money
> with the antenna mounted like so many are.
> I wish some knowledgeable person with the right equipment would
> make some field strength measurements on these installations vs.
> some with the antenna mounted external to the airplane. If the
> results are comparable, I'll gladly eat my words.
> I'm sure this won't be a very popular post, but it needed to be said.
> Dan Hopper
> RV-7A
> Flying since 2004
>
> *
>
> ="http://www.matronics.com/Navigator?RV-List">http://www.matronics.com/Navigator?RV-List
> s.matronics.com/ <http://s.matronics.com/>">http://forums.matronics.com
> p://www.matronics.com/contribution">http://www.matronics.com/contribution
>
> *
>
> *
>
> ===================================
> /www.matronics.com/Navigator?RV-List
> ===================================
> cs.com
> ===================================
> matronics.com/contribution
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>
> *
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No virus found in this message.
Checked by AVG - www.avg.com
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