Today's Message Index:
----------------------
1. 04:56 AM - Re: Re: ELT Antenna Location (Bill Denton)
2. 06:17 AM - Shower of Sparks Ignition (John Crate)
3. 09:35 AM - Re: Shower of Sparks Ignition (Robert L. Nuckolls, III)
4. 07:26 PM - Gross Antenna Modification (DAVID REEL)
5. 08:32 PM - Re: Gross Antenna Modification (Dave Morris \)
6. 09:35 PM - Re: Gross Antenna Modification (Leo Corbalis)
7. 10:20 PM - Re: 2006 Seminar Schedule (Gerry Holland)
Message 1
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| Subject: | Re: ELT Antenna Location |
--> AeroElectric-List message posted by: "Bill Denton" <bdenton@bdenton.com>
JFTR: The Artex ME 406 uses a single antenna for both 121.5 & 406 mHz. Under
$1,000 with a whip antenna rated for < 200 kias...
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of
gmcjetpilot@yahoo.com
Subject: AeroElectric-List: Re: ELT Antenna Location
--> AeroElectric-List message posted by: <gmcjetpilot@yahoo.com>
FAA requires ELTs meet TSO C-91a. The ELT should be installed per the
manufactures TSO approved installation data and instructions. The
manufacture can only make suggestions. The installer certifies the
installation is acceptable. However the antenna is an approved part of the
ELT's TSO. Substitution of a rubber duck antenna is dubious, unless you test
it. Also aviation circular AC 43.13-2A, Chapter 2 Paragraph 28 states
"Follow the manufactures installation procedures when available".
The requirement for an ELT, per FAR part 91.207, does NOT address
installation except to say:
91.207(d)(1) Each emergency locator transmitter required by paragraph (a) of
this section must be inspected ..........for -- (1) Proper installation.
Proper installation means, following the approved installation, parts and
instructions? However as the installer you approve it.
My ELT came with the installation instructions: ELT unit and antenna be
mounted so the coax is routed not to cross a bulkhead, requires the
(supplied) antenna be mounted external to the aircraft, vertically and at a
location as far away as practical from other antennas. The instructions also
specify strength of the mounting brackets for ELT and antenna (100 times
the static weight of the ELT or antenna). If there is a chance the structure
can deform and pull the coax out a tether needs to be installed between the
antenna mount and ELT unit mount. Install as far aft as possible (baggage
compartment OK).
Now Rubber ducky antennas, mounting antennas horizontal inside the wing tip,
tail fairing or in the cockpit can work, but it is not per the manufactures
instructions (unless using the all in one EBC ELT). Even experimental
aircraft must meet part 91. Part 91 requires a TSO'ed C-91a, end of story.
Cel Phones, Sat phones are great, smoke signals, personal hand held 406 ELTs
(w/ internal GPS position) are also cool
http://www.tlrsystems.com/products/personal-locator-beacon.html
However these above devices do not negate the regulation for an aircraft
mounted ELT that automatically activates. When the 406 units are required
you will have two antennas to deal with. The new ELTs use two antennas, one
for the 121.5 freq and another for the 406 freq.
I will leave the debate about whether an ELT can save your life to the
experts.G
>Date: Sep 01, 2005
>From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
>Subject: Re: ELT Antenna Location
>
>
>ELT antenna location
>
>I am installing an ELT in my RV-6 aircraft. Since it has a plastic canopy,
>it would seem that the antenna can be installed inside the fuselage under
>the canopy. Are there any special rules regarding separation from metal
>structure such as side walls? I am aware of the common requirements, i.e.
>vertical orientation, closeness to other antennas, etc.
There are no "rules" . . . only a handful of suggestions
for optimizing performance in case the ELT is really needed.
But given all the variables that surface after the crumpling
and rolling has stopped, there is nothing you can do that will
optimize ELT operations for all foreseeable outcomes.
Given further that ELT's add almost nothing to your chances
of survival in an accident, it seems that ANY way you want
to install it will comply with the letter of Part 91 even
if it misses the intent by a country mile. Keep a VHF Comm
hand held, cellphone and GPS in your flight bag . . . if you're still
up and running after the airplane is dead, these critters
will contribute far more to your chances of survival than the
ELT.
Bob . . .
---------------------------------
Message 2
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| Subject: | Shower of Sparks Ignition |
--> AeroElectric-List message posted by: "John Crate" <john.crate@encode.com>
Bob
I have read your excellent article on shower of sparks ignition. I am
confused on one point. In the article, it shows unshielded wire between the
BO terminal on the key switch and the vibrator. The aircraft that
everything came out of used shielded wire for this application. Can you
please comment.
Thanks
John
---
Message 3
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| Subject: | Re: Shower of Sparks Ignition |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 09:14 AM 9/3/2005 -0400, you wrote:
>--> AeroElectric-List message posted by: "John Crate" <john.crate@encode.com>
>
>Bob
>
>I have read your excellent article on shower of sparks ignition. I am
>confused on one point. In the article, it shows unshielded wire between the
>BO terminal on the key switch and the vibrator. The aircraft that
>everything came out of used shielded wire for this application. Can you
>please comment.
In only a very few instances does shielded wire hurt or degrade
performance of a system . . . and usually in surprising
ways. I've worked a trim system on a biz jet where shielded
wire was called out for mechanical robustness but the physics
of the shielding contributed to poor relay contact performance
that led to sticking contacts and runaway trim systems. In the
instance you've cited, there's no evil in wiring the BO lead
with shielded wire but give that it's only active while the
starter is engaged, whatever noise might propagate from this
wire is temporary and usually insignificant.
Bob . . .
Message 4
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| Subject: | Gross Antenna Modification |
--> AeroElectric-List message posted by: "DAVID REEL" <dreel@cox.net>
Would a 1/4 wave vertical antenna cut for 121.5 Mhz be more effective if it were
truncated 6 inches at the tip or bent so that it was 6 inches shorter? Although
I may still use a mid-loading coil to shorten the length, I would still like
to know the answer should my back be to the wall.
Dave Reel - RV8A
Message 5
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| Subject: | Re: Gross Antenna Modification |
--> AeroElectric-List message posted by: "Dave Morris \"BigD\"" <BigD@DaveMorris.com>
Cutting 6 inches off a 1/4 wave antenna will totally shift its resonant
frequency outside the aircraft band, reducing the output of the transmitter
quite a bit. I would rather bend it around to keep as much of the original
length as possible... if you have to bend it 180 degrees back on itself,
that's just as bad as cutting it. If there is a coil available for that
antenna that will preserve the resonant frequency, that is the best
solution. Is this for an ELT or for a COM radio?
Dave Morris
At 09:26 PM 9/3/2005, you wrote:
>--> AeroElectric-List message posted by: "DAVID REEL" <dreel@cox.net>
>
>Would a 1/4 wave vertical antenna cut for 121.5 Mhz be more effective if
>it were truncated 6 inches at the tip or bent so that it was 6 inches
>shorter? Although I may still use a mid-loading coil to shorten the
>length, I would still like to know the answer should my back be to the wall.
>
>Dave Reel - RV8A
>
>
Message 6
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| Subject: | Re: Gross Antenna Modification |
--> AeroElectric-List message posted by: "Leo Corbalis" <leocorbalis@sbcglobal.net>
A mid loading coil might raise hell by vibrating in the wind which is a bit
stronger than on a car. Use the full antenna. You may need all the range you
can get when it really really matters
Leo Corbalis
----- Original Message -----
From: "DAVID REEL" <dreel@cox.net>
Subject: AeroElectric-List: Gross Antenna Modification
> --> AeroElectric-List message posted by: "DAVID REEL" <dreel@cox.net>
>
> Would a 1/4 wave vertical antenna cut for 121.5 Mhz be more effective if
> it were truncated 6 inches at the tip or bent so that it was 6 inches
> shorter? Although I may still use a mid-loading coil to shorten the
> length, I would still like to know the answer should my back be to the
> wall.
>
> Dave Reel - RV8A
>
>
>
Message 7
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| Subject: | Re: 2006 Seminar Schedule |
--> AeroElectric-List message posted by: Gerry Holland <gholland@gemini-resourcing.com>
Bob Hi from UK!
> If anyone out there knows their EAA chapter programs/activities
> chairperson and thinks they'd be interested in hosting a seminar,
> I'd be pleased to hear from them. Right now, the 2006 calendar is
> wide open. Thanks!
I'm asking via the list whether a trip to the UK is possible for an Event
such as the PFA Rally in July 2006 where we also have many visitors from
Europe and beyond. Lots of people here refer to your documentation and use
the list. If there is a good response is that of interest?
Regards
Gerry
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