radar and gliders !

[Mal[_1_]]

I was listening to Sydney radar the area frequency and 122.7 my VHF radio
scans very fast on Saturday afternoon they picked up a glider with the radar
as a primary target and it was giving them height as well they are they
running new software to filter aircraft.

No wonder when persons are posting IGC files on the OLC infringing Sydney's
controlled airspace in the same glider maybe they will get the message when
the federal police turn up and arrest them.

--
Mal

www.mals.net

[Eric Greenwell[_1_]]

Mal wrote:
> I was listening to Sydney radar the area frequency and 122.7 my VHF radio
> scans very fast on Saturday afternoon they picked up a glider with the radar
> as a primary target and it was giving them height as well they are they
> running new software to filter aircraft.

Do you know how they were getting the altitude? Perhaps by reports from
other aircraft?

[Gerhard Wesp[_5_]]

Eric Greenwell > wrote:
> Do you know how they were getting the altitude? Perhaps by reports from
> other aircraft?

Can't the radar measure the angle between the target and the horizon?
This would give you an estimate of altitude, as you know the distance...

Regards
-Gerhard
--
Gerhard Wesp / Holderenweg 2 / CH-8134 Adliswil
+41 (0)76 505 1149 (mobile) / +41 (0)44 668 1878 (office)
+41 (0)44 668 1818 (fax)
http://gwesp.tx0.org/

[Mark Dickson]

Unless the glider was transponder equipped, the only
radar that could give the height would be a Precision
Approach Radar (Talkdown). This only scans 10 degrees
either side of the runway centreline and is not widely
used at civilian airports. If ATC knew the height
I think it would have been via a report from another
aircraft.


At 17:42 21 August 2006, Gerhard Wesp wrote:
>Eric Greenwell wrote:
>> Do you know how they were getting the altitude? Perhaps
>>by reports from
>> other aircraft?
>
>Can't the radar measure the angle between the target
>and the horizon?
>This would give you an estimate of altitude, as you
>know the distance...
>
>Regards
>-Gerhard
>--
>Gerhard Wesp / Holderenweg 2 / CH-8134 Adliswil
>+41 (0)76 505 1149 (mobile) / +41 (0)44 668 1878 (office)
>+41 (0)44 668 1818 (fax)
>http://gwesp.tx0.org/
>

[Eric Greenwell[_1_]]

Gerhard Wesp wrote:
> Eric Greenwell > wrote:
>> Do you know how they were getting the altitude? Perhaps by reports from
>> other aircraft?
>
> Can't the radar measure the angle between the target and the horizon?
> This would give you an estimate of altitude, as you know the distance...

The standard ATC radar has a narrow beam horizontally and a broad beam
vertically, so no, normally it can't measure the angle with the ground.
Take a look at most radar antennas, and you see the antenna shape is the
opposite of this (broad horizontally, narrow vertically). To have a
narrow beam horizontally and vertically would require a antenna that was
large in both directions. Even so, it would not be accurate enough for
ATC purposes, nor would it measure what the airplane's altimeter was
measuring, thus the use of transponders.

--
Change "netto" to "net" to email me directly

Eric Greenwell - Washington State, USA

www.motorglider.org - Download "A Guide to Self-launching Sailplane
Operation"

[Lew Hartswick]

Mark Dickson wrote:
> Unless the glider was transponder equipped, the only
> radar that could give the height would be a Precision
> Approach Radar (Talkdown). This only scans 10 degrees
> either side of the runway centreline and is not widely
> used at civilian airports. If ATC knew the height
> I think it would have been via a report from another
> aircraft.
>
Back in "good old days" I worked on a CPS 6B which gave
height by a second "slant" beam displaced from the
"vert" beam by, as I remember 10 deg.
Gosh that was a LOOOOONG time ago. :-)
...lew...

[Don Johnstone]

At 23:00 21 August 2006, Lew Hartswick wrote:
>Mark Dickson wrote:
>> Unless the glider was transponder equipped, the only
>> radar that could give the height would be a Precision
>> Approach Radar (Talkdown). This only scans 10 degrees
>> either side of the runway centreline and is not widely
>> used at civilian airports. If ATC knew the height
>> I think it would have been via a report from another
>> aircraft.

I think you will find that air defence radars are very
capable of giving an accurate height and in many cases
civilian air traffic radars are taking a feed from
the very same radar heads as the military. Plus there
is a deal more co-operation between the civilian and
military radars in the present climate. The feed that
the civilian world gets from the military heads is
only cut down in range and tailored to the need of
the controller.

Many years ago I visited a local airfield radar and
they did not have their own radar transmitter. They
used a feed from the Air Defence radar situated just
down the road.

[Mal[_1_]]

"Don Johnstone" > wrote in message
...
> At 23:00 21 August 2006, Lew Hartswick wrote:
>>Mark Dickson wrote:
>>> Unless the glider was transponder equipped, the only
>>> radar that could give the height would be a Precision
>>> Approach Radar (Talkdown). This only scans 10 degrees
>>> either side of the runway centreline and is not widely
>>> used at civilian airports. If ATC knew the height
>>> I think it would have been via a report from another
>>> aircraft.
>
> I think you will find that air defence radars are very
> capable of giving an accurate height and in many cases
> civilian air traffic radars are taking a feed from
> the very same radar heads as the military. Plus there
> is a deal more co-operation between the civilian and
> military radars in the present climate. The feed that
> the civilian world gets from the military heads is
> only cut down in range and tailored to the need of
> the controller.
>
> Many years ago I visited a local airfield radar and
> they did not have their own radar transmitter. They
> used a feed from the Air Defence radar situated just
> down the road.
>
>
>

http://www.dg-flugzeugbau.de/radar-reflector-e.html

http://www.cap.gov/visitors/news/cap_news_online/index.cfm?fuseaction=display&nodeID=6192&newsID=1918&year=2005&month=12

Would appear that they can get a primary paint sent an email to airservices
and asked the same question I asked in here lets see what they say.

Mal

[Don Johnstone]

I think you will find that and ordinary primary radar
can give an approximate height when processed. This
'Height' is not accurate enough to provide seperation
for controllers but is available. The slant range to
the target is used as one measurement and the other
is the point on the globe over which the target is.
with two sides known of a right angled triangle the
third side is calculated by using Pythagorus, the square
of the hypotenuse is equal to the sum of the squares
on the other two sides, the slant range being the hypotenuse.


At 03:36 22 August 2006, Mal wrote:
>
>'Don Johnstone' wrote in message
...
>> At 23:00 21 August 2006, Lew Hartswick wrote:
>>>Mark Dickson wrote:
>>>> Unless the glider was transponder equipped, the only
>>>> radar that could give the height would be a Precision
>>>> Approach Radar (Talkdown). This only scans 10 degrees
>>>> either side of the runway centreline and is not widely
>>>> used at civilian airports. If ATC knew the height
>>>> I think it would have been via a report from another
>>>> aircraft.
>>
>> I think you will find that air defence radars are
>>very
>> capable of giving an accurate height and in many cases
>> civilian air traffic radars are taking a feed from
>> the very same radar heads as the military. Plus there
>> is a deal more co-operation between the civilian and
>> military radars in the present climate. The feed that
>> the civilian world gets from the military heads is
>> only cut down in range and tailored to the need of
>> the controller.
>>
>> Many years ago I visited a local airfield radar and
>> they did not have their own radar transmitter. They
>> used a feed from the Air Defence radar situated just
>> down the road.
>>
>>
>>
>
>http://www.dg-flugzeugbau.de/radar-reflector-e.html
>
>http://www.cap.gov/visitors/news/cap_news_online/index.cfm?fuseact
>>ion=display&nodeID=6192&newsID=1918&year=2005&month=12
>
>Would appear that they can get a primary paint sent
>an email to airservices
>and asked the same question I asked in here lets see
>what they say.
>
>Mal
>
>
>

[Mark Dickson]

Air traffic Controllers have no way of telling the
altitude of an aircraft without SSR or a talkdown radar.
Air defenders used height finding radar which is not
available at civil units (I don't think it's in use
anymore; maybe). Some civil units in the UK have made
use of Air Traffic radar at military units, but this
is straight forward ATC equipment, the same as at any
airport.


At 11:06 22 August 2006, Don Johnstone wrote:
>I think you will find that and ordinary primary radar
>can give an approximate height when processed. This
>'Height' is not accurate enough to provide seperation
>for controllers but is available. The slant range to
>the target is used as one measurement and the other
>is the point on the globe over which the target is.
>with two sides known of a right angled triangle the
>third side is calculated by using Pythagorus, the square
>of the hypotenuse is equal to the sum of the squares
>on the other two sides, the slant range being the hypotenuse.
>
>
>At 03:36 22 August 2006, Mal wrote:
>>
>>'Don Johnstone' wrote in message
...
>>> At 23:00 21 August 2006, Lew Hartswick wrote:
>>>>Mark Dickson wrote:
>>>>> Unless the glider was transponder equipped, the only
>>>>> radar that could give the height would be a Precision
>>>>> Approach Radar (Talkdown). This only scans 10 degrees
>>>>> either side of the runway centreline and is not widely
>>>>> used at civilian airports. If ATC knew the height
>>>>> I think it would have been via a report from another
>>>>> aircraft.
>>>
>>> I think you will find that air defence radars are
>>>very
>>> capable of giving an accurate height and in many cases
>>> civilian air traffic radars are taking a feed from
>>> the very same radar heads as the military. Plus there
>>> is a deal more co-operation between the civilian and
>>> military radars in the present climate. The feed that
>>> the civilian world gets from the military heads is
>>> only cut down in range and tailored to the need of
>>> the controller.
>>>
>>> Many years ago I visited a local airfield radar and
>>> they did not have their own radar transmitter. They
>>> used a feed from the Air Defence radar situated just
>>> down the road.
>>>
>>>
>>>
>>
>>http://www.dg-flugzeugbau.de/radar-reflector-e.html
>>
>>http://www.cap.gov/visitors/news/cap_news_online/index.cfm?fuseact
>>>
>>>ion=display&nodeID=6192&newsID=1918&year=2005&month=12
>>
>>Would appear that they can get a primary paint sent
>>an email to airservices
>>and asked the same question I asked in here lets see
>>what they say.
>>
>>Mal
>>
>>
>>
>
>
>
>

[Eric Greenwell[_1_]]

Don Johnstone wrote:
> I think you will find that and ordinary primary radar
> can give an approximate height when processed. This
> 'Height' is not accurate enough to provide seperation
> for controllers but is available. The slant range to
> the target is used as one measurement and the other
> is the point on the globe over which the target is.

How do they determine where this point is? The radar I'm familiar with
only gives the slant range.
--
Change "netto" to "net" to email me directly

Eric Greenwell - Washington State, USA

www.motorglider.org - Download "A Guide to Self-launching Sailplane
Operation"