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  #1  
Old 11-08-2019, 03:29 PM
VA Maule VA Maule is offline
 
Join Date: Apr 2016
Location: Bucking ham, Virginia
Posts: 175
Default 406 ELT

Working on the installation of an Artex 345 ELT. The instructions are not very helpful regarding antenna installation " Select a suitable location where the antenna can be installed vertically "&" guidance may be found in AC 43.13-2, Chapter 3 ". With this unit ( all 406 ELT) sending their signal to a satellite the antenna must be installed on the top side of the airplane per Artex technical support.
So here's the question has anyone figured out where to install the antenna? Per my attempts at selecting a location no suitable location can be found on a RV-8 with a slider canopy. To the exterm rear of the fuselage where it's not interfering with the rear canopy skirt the wind blasts would cause the stainless steel whip beat upon the vertical stabilizer.
In the call to Tec support when I explained my plight the guy I spoke with he didn't know what a RV8 is and when I explained what it was his reply was "we don't do experimental "
Any ideas or suggestions
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  #2  
Old 11-09-2019, 03:10 AM
flyinga flyinga is offline
 
Join Date: Dec 2007
Location: Fredericksburg, TX
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I put mine on the aft portion of the right back-seat armrest.

The concern I have is that if you make an off airport landing there's a good chance the airplane will end up on its top; therefore the antenna should be on the bottom???
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  #3  
Old 11-09-2019, 12:39 PM
Canadian_JOY Canadian_JOY is online now
 
Join Date: Aug 2007
Location: Ontario, Canada
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One location that works at least somewhat well is just aft of the canopy in the fully open position, canted at about 10 or 11 o'clock when viewed from behind the aircraft, bisecting the angle between horizontal and vertical stabilizers.

The '8 with a slider makes antenna installation a challenge - there's just not much real estate available.
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  #4  
Old 11-09-2019, 07:06 PM
Ralph Inkster Ralph Inkster is offline
 
Join Date: Feb 2008
Location: Calgary, Alberta
Posts: 561
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If there is a good mounting spot on a RV-8 for the ELT antenna, I'm still looking for it.
Less than ideal spots
- Best less than ideal spot- right above the F-807-1 bulkhead, on the front edge of the turtle deck skin, you might have to notch the antenna base to clear the canopy frame when closed, bend the antenna wire sideways & attach rubber knob so it doesn't scratch the canopy. Best exposure but ground plane compromised.
- A bit more less than ideal- mount on rt arm rest, secure antenna wire so it doesn't stab passenger, questionable broadcast properties as is sheltered.
- Again lower on the ideal scale- mount on right cockpit side wall so antenna wip sticks up through roll over cross bar, more open but bars very disruptive to broadcast but is mostly out of the way for passenger.
- Maybe more ideal if you pre-plan to crash upside down- under horizontal stab pointing out the side of the fuselage, bend the wip portion of antenna back, kind of protected area, as mentioned preferred if you do end upside down, probably will need replacing every so often due to turbulent air flow causing fatigue damage to the wip.
- Worst ideal spot- bracket on upper edge of firewall in engine compartment- I think that is a crush zone...

Canadian Joy suggested a good spot actually. A alternative would be to mount directly ahead of the Vert Stab and fashion a notch into the canopy skirt to clear the antenna base (dreaded fiberglass work though). & consider controlling antenna wip damage to the Vert Stab some how.
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  #5  
Old 11-09-2019, 07:44 PM
VA Maule VA Maule is offline
 
Join Date: Apr 2016
Location: Bucking ham, Virginia
Posts: 175
Default No good spots

The idea of clocking between 10 to 11 as far aft as possible is the better option other than the issue of working in the very narrow tail cone. I'll have to do a test fit of myself to see if it would even be possible to get me far enough in there to get the job done ( note to self make sure to have a helper to pull me out)

Believe I'll have to think about this a while longer. In the meantime any more ideas and suggestions are truly appreciated
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  #6  
Old 11-10-2019, 07:39 AM
swordtail swordtail is offline
 
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Location: Grindstone, PA
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If you put the antenna on the side of the plane it won't matter if you crash face up or down. Just saying!
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  #7  
Old 11-10-2019, 10:01 AM
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Snowflake Snowflake is offline
 
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Location: Victoria, BC, Canada
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Quote:
Originally Posted by swordtail View Post
If you put the antenna on the side of the plane it won't matter if you crash face up or down. Just saying!
But it will matter if you crash on your left or right side.

How about mounting it in the fairing that covers the vertical to horizontal stab intersection? It's been a while since i've looked at an -8, but that must be behind the -8 canopy when it's open?

You could even go back down one side of the vertical stab, and mount it on an angle between the two... Of course you're back to the "which side do I crash on" question.
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  #8  
Old 11-10-2019, 10:25 AM
Jpm757 Jpm757 is offline
 
Join Date: May 2013
Location: Sherman, CT
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I still like a horizontal mounting under the fiberglass empennage fairing. Protected during accident sequence and again, who knows what attitude the bird will wind up. Any external mount is more susceptible to damage. Some DAR's frown upon this setup and require mounting per manufacturers instructions.
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Last edited by Jpm757 : 11-10-2019 at 10:26 AM. Reason: Add
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  #9  
Old 11-10-2019, 10:42 AM
Canadian_JOY Canadian_JOY is online now
 
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Location: Ontario, Canada
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Quote:
Originally Posted by Jpm757 View Post
I still like a horizontal mounting under the fiberglass empennage fairing. Protected during accident sequence and again, who knows what attitude the bird will wind up. Any external mount is more susceptible to damage. Some DAR's frown upon this setup and require mounting per manufacturers instructions.
While you may well like that installation location, the reality is that it absolutely sucks from the perspective of Radio Frequency performance. After all, it's an antenna, so it's job is to work at radio frequencies. By installing the antenna under the empennage fairing one is grossly handicapping ELT performance right out of the box.

Yes, any external antenna can be swept off in the crash sequence. In fact it's likely safest to say that any antenna installation is a bit of a **** shoot since we really have no idea what will happen in a crash. All we can do is our very utmost to make the ELT installation as good as we possibly can, to put as many variables to work in our favor, then hope the crash isn't terribly violent.
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  #10  
Old 11-10-2019, 04:03 PM
Jpm757 Jpm757 is offline
 
Join Date: May 2013
Location: Sherman, CT
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AC 91-44A allows for internal ELT antenna mounting when external mount is not practicle. You determine practicle.
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RV6 #20477 completed 1991 sold.
RV7 #72018 N767T first flight 11/21/2017 250+ hrs.
IO-360M1B MT 3 blade, Dual AFS 5600 QUICK Panel.
Manual Flaps. KOXC Oxford, CT
1941 J3 Cub skis,floats.
2019 dues gladly paid.

Last edited by Jpm757 : 11-10-2019 at 04:04 PM. Reason: Add
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