Today's Message Index:
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1. 07:38 AM - Re: Transponder antenna ground plane (Eric Page)
2. 09:22 AM - Re: Re: Transponder antenna ground plane (Robert L. Nuckolls, III)
3. 10:35 AM - Re: Re: Transponder antenna ground plane (Charlie England)
4. 11:37 AM - A fascinating watch . . . (Robert L. Nuckolls, III)
5. 11:52 AM - Re: A fascinating watch . . . (Daniel Clark)
6. 01:13 PM - Re: A fascinating watch . . . (Bill Settle)
Message 1
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| Subject: | Re: Transponder antenna ground plane |
Yes, I seem to remember reading something about that. I have no plans to fly into
Canada, but I wonder what will be required, hardware-wise, to satisfy their
requirement. I presume you would need a transponder designed for multiple antennas.
It looks like uAvionix's tailBeaconX satisfies the Canadians, but beyond
that, I have no idea!
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=506545#506545
Message 2
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| Subject: | Re: Transponder antenna ground plane |
At 09:41 PM 4/12/2022, you wrote:
>
>Next year Canada is going to require aircraft flying in Class A & B
>airspace to be able to send transponder signals to satellites. This
>requirement can be met either through antenna diversity (the use of
>a top and bottom antenna) or with a single antenna that is capable
>of transmitting both towards the ground and up towards satellites.
> I have never seen transponder antennas on top of airplanes
> either. But chances are that an antenna on top would work just as
> well as one on the bottom.
The quater-wave, ground-plane antenna has a
radiation patter like shown in this illustration.
Very attenuated response 'below' the ground plane.
Probably even more attenuation on a 'large' ground
plane like an aircraft skin.
Looking at the elevation pattern we see the major
lobe is displaced about 30 degrees off the ground
plane . . . i.e. favoring ground based stations
when mounted upside down. Response out to the
horizon is only down 3db . . .
Talking to satellites? Got any links to
expand on that? I'm wondering what service is
expected to use xponder data . . . and for
what purpose.
Bob . . .
Un impeachable logic: George Carlin asked, "If black boxes
survive crashes, why don't they make the whole airplane
out of that stuff?"
Message 3
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| Subject: | Re: Transponder antenna ground plane |
On 4/13/2022 11:17 AM, Robert L. Nuckolls, III wrote:
> At 09:41 PM 4/12/2022, you wrote:
>>
>> Next year Canada is going to require aircraft flying in Class A & B
>> airspace to be able to send transponder signals to satellites. This
>> requirement can be met either through antenna diversity (the use of a
>> top and bottom antenna) or with a single antenna that is capable of
>> transmitting both towards the ground and up towards satellites.
>> I have never seen transponder antennas on top of airplanes either.
>> But chances are that an antenna on top would work just as well as one
>> on the bottom.
>
> The quater-wave, ground-plane antenna has a
> radiation patter like shown in this illustration.
> Very attenuated response 'below' the ground plane.
> Probably even more attenuation on a 'large' ground
> plane like an aircraft skin.
>
> Looking at the elevation pattern we see the major
> lobe is displaced about 30 degrees off the ground
> plane . . . i.e. favoring ground based stations
> when mounted upside down. Response out to the
> horizon is only down 3db . . .
>
> Talking to satellites? Got any links to
> expand on that? I'm wondering what service is
> expected to use xponder data . . . and for
> what purpose.
It's just ADS-B, with a/c transmissions received by satellites. To the
FAA: Can I get a 'duh...'?
https://aireon.com/resources/overview-materials/its-just-ads-b/
Charlie
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Message 4
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| Subject: | A fascinating watch . . . |
Get a bowl of popcorn and a large enough jug to last
80 minutes. Found this documentary to be rather
spell binding . . .
https://youtu.be/2ayA2UE-p8M
Bob . . .
Un impeachable logic: George Carlin asked, "If black boxes
survive crashes, why don't they make the whole airplane
out of that stuff?"
Message 5
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| Subject: | Re: A fascinating watch . . . |
Great documentary on Bob Hoover !
>
> Get a bowl of popcorn and a large enough jug to last
> 80 minutes. Found this documentary to be rather
> spell binding . . .
>
> https://youtu.be/2ayA2UE-p8M
>
>
> Bob . . .
>
> Un impeachable logic: George Carlin asked, "If black boxes
> survive crashes, why don't they make the whole airplane
> out of that stuff?"
>
Message 6
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| Subject: | A fascinating watch . . . |
Bob,
Thanks for sharing!
Bill Settle
From: owner-aeroelectric-list-server@matronics.com
<owner-aeroelectric-list-server@matronics.com> On Behalf Of Robert L.
Nuckolls, III
Sent: Wednesday, April 13, 2022 2:37 PM
Subject: AeroElectric-List: A fascinating watch . . .
Get a bowl of popcorn and a large enough jug to last
80 minutes. Found this documentary to be rather
spell binding . . .
https://youtu.be/2ayA2UE-p8M
Bob . . .
Un impeachable logic: George Carlin asked, "If black boxes
survive crashes, why don't they make the whole airplane
out of that stuff?"
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