RADAR questions?

chunk75 · January 27th, 2003, 22:01

Anybody have any RADAR questions? It's an area I know something about and I don't mind answering. It keeps it fresh in my noodle.

Chunk

darrenf · January 28th, 2003, 05:46

[ QUOTE ]
Anybody have any RADAR questions? It's an area I know something about and I don't mind answering. It keeps it fresh in my noodle.

Chunk

[/ QUOTE ]

I have one,
Do you think he ever got to sample Hot Lips??

ready2fly · January 28th, 2003, 07:26

!!!!!!!!!!!!

chunk75 · January 28th, 2003, 08:46

I remember one episode where Radar took a paternity test....I guess he had too much Grape Ne-Hi one night.

Chunk

CaliforniaSurfer · January 28th, 2003, 18:17

What the hell are you guys talking about?

E_Dawg · January 28th, 2003, 18:57

I knew there was a MASH joke in here somewhere!!!!

reaperman · January 28th, 2003, 20:01

RADAR. They're talking about RADAR. Look at the subject line. Sheesh!!

haree · February 3rd, 2003, 09:19

ok here goes.....

I have been in atcs for quite sometime now... how do the radars track the expected altitude IAS etc.. of the aircraft,,,,

General one: wouldnt it be bad if someone using a radar can estimate an A/cs settings;;;;

ready2fly · February 3rd, 2003, 09:33

haree - your Mode C transponder emits a signal that allows radar to "see" your altitude.

chunk75 · February 3rd, 2003, 18:18

haree....can you clarify/amplify your question a bit...

Eagle · February 4th, 2003, 18:07

[ QUOTE ]
how do the radars track the expected altitude IAS etc.. of the aircraft,,,,

[/ QUOTE ]

the expected altitudes are on the flight plan for each aircraft.

the air speed is of no real importance (ICAS/TAS) as it is all relaitive to the other airplanes in the the line. you will be told to slow down or speed up to keep the spacing.

you may get:

Atc: Lear N34J, say airspeed.
us: .78
atc: Lear N34J, maintain .7 in the decent.
us: 4J

or a decent climb at PIC descretion,

once below the FLs it switches over to kts vs M.

chunk75 · February 4th, 2003, 20:31

Also, RADAR doesn't give a lick about IAS/TAS, it only works in GS.

Distance from antenna @ 'paint' A minus Distance from antenna @ 'paint'B divided by the difference in time in between paints = GS. Distance from antenna is determined by total time from pulse to return of echo divided by 12.36 microseconds (the time required for RADAR waves to travel one mile and back).

Of course, you're talking about multiple paints in one sweep. A paint is one pulse and one echo.

Chunk

ready2fly · February 5th, 2003, 08:35

[ QUOTE ]
Distance from antenna @ 'paint' A minus Distance from antenna @ 'paint'B divided by the difference in time in between paints..

[/ QUOTE ]
chunk, is it "paints" or "POINTS"??

Paint = like an image "painted" on the screen?

Please advise. First I've heard that term.

Thanks
R2F

chunk75 · February 5th, 2003, 13:03

A 'paint' is a unofficial, or technical slang, term for "illuminating" a target. Bouncing RADAR energy off of a target is called painting. Sometimes you'll hear the term "skin paint" which is getting a RADAR return unamplified by transponders. It is fairly uncommon for ATC RADAR to skin paint targets unless the aircraft has a large RADAR cross section (RCS) or they are close to the antenna. Approach RADAR's are more likely to get skin paints than Center RADAR because of the precision of the set. Center sets are long range EW (Early Warning) sets meant for max range at the expense of precision. Of course, precision is a relative term....center RADAR may have a resolution of .5nm while an approach set may have a range resolution of .01nm. These numbers are educated guesses...without the parameters of the set, I can't be certain. ATC RADAR relies on transponders to make targets noticable. Military RADAR, on the other hand, has to be powerful enough to rely on skin paints. An enemy target certainly isn't going to have a transponder on to boost the reply.

Clear as mud?

Chunk

ready2fly · February 5th, 2003, 14:41

[ QUOTE ]
Clear as mud?

[/ QUOTE ]

Ah. Clear as mud. Thanks.

haree · February 8th, 2003, 04:37

Gee...Thanks That was few of the great replies...

Eagle · February 8th, 2003, 06:14

[ QUOTE ]
Also, RADAR doesn't give a lick about IAS/TAS, it only works in GS.

[/ QUOTE ]

which is sorta interesting,

figure you are doing 150kts ICAS, but your GS is 200kts. ATC sees 200kts and will make all assignments based on that, so you have a 50 kt tailwind, everyone does, that is headed your way. Many times I have heard. N1234 what kind of airplane are you? we are a baron sir, ATC.. huh, N1234, yeah winds. ( Assuming this guy is getting plowed with a headwind. the converse is also true I have heard Skyhawks begging ATC for a GS because they are in a 30-50kt tailwind. I don't know but can find out if anyone is really interested, if ACT keeps the head/tail winds in mind when you are given course changes.

Mavmb · February 16th, 2003, 22:40

I've got a question actually. Can ATC see the Transponders when you're on the ground waiting for takeoff? I'm assuming they can when you have it switched to altitude but I wasn't sure.

mikek123 · February 16th, 2003, 23:15

[ QUOTE ]
I've got a question actually. Can ATC see the Transponders when you're on the ground waiting for takeoff? I'm assuming they can when you have it switched to altitude but I wasn't sure.

[/ QUOTE ]

I belive it depends on where their radar is located and where you are on the airport. If the secondary radar antenna can't pick up your transponders signal then no, if there is nothing blocking the path between your transponder antenna and the radar than they can see you.

E_Dawg · February 16th, 2003, 23:34

Yeah it absouletely depends on where the radar antenna is located; if you fly out over the ocean here in socal and descend below 500 - 1000 AGL you are virtually guarenteed to get a great big 'RADAR CONTACT LOST' from ATC. If they lose you at 500 feet over nothing but water I'd say it's a great bet they can't see you at all on the ground unless the antenna is actually on the field.

....which brings me to another question: where are the antennas usually located? ...airports? hilltops?

drumminpilot · February 16th, 2003, 23:46

[ QUOTE ]
where are the antennas usually located? ...airports? hilltops?

[/ QUOTE ]

One of the ones around here is about a mile or so off the airport on top of a hill, another one is on a tower at the airport.

A question: Can ATC turn on a filter for traffic thats on the ground? I thought I remember one of the tower guys here telling me they could.....

mikek123 · February 16th, 2003, 23:47

[ QUOTE ]
which brings me to another question: where are the antennas usually located?

[/ QUOTE ]

I know alot of them are located at the airport usually on top of a building. In Daytona the radar is about 5 miles nw of the field. I guess it just depends on teh surroundings of the airport and how much room they have to put up a radar.

reaperman · February 17th, 2003, 10:02

They can see you on the ground at OLS. "They" being the DEA and/or anyone else who's supposed to watch the Mexican border. If you are on the ground at OLS, about to taxi for takeoff, you are advised to have your transponder reporting altitude before you get moving.

They don't need to worry about, or check out a contact that they've seen motionless or just coming off the ground at a friendly airport. But if they first notice you flying low in a small plane five miles from the border, they might have to take an interest in you.I don't know if the equipment is in the balloon tethered thirty miles East, or in planes that patrol the border.

pavelump · February 17th, 2003, 10:33

When I landed in Valdosta, GA the ground/tower controller said, "Taxi to the ramp. And you can turn your transponder off." Ooops. Boy did I feel like a boob.

Dave

eodfe · February 17th, 2003, 12:38

On a slow morning at APA (not very often) After runup I turned on my transponder and tower without me calling and saying ready for takeoff, cleared me for takeoff.

January 27th, 2003, 22:01	#1
chunk75 Senior Member Join Date: Jul 2001 Location: FL Posts: 922	RADAR questions? Anybody have any RADAR questions? It's an area I know something about and I don't mind answering. It keeps it fresh in my noodle. Chunk

January 28th, 2003, 05:46	#2
darrenf Old Skool Join Date: Feb 2002 Location: Atlantic City, NJ Posts: 3,987	Re: RADAR questions? [ QUOTE ] Anybody have any RADAR questions? It's an area I know something about and I don't mind answering. It keeps it fresh in my noodle. Chunk [/ QUOTE ] I have one, Do you think he ever got to sample Hot Lips??

January 28th, 2003, 07:26	#3
ready2fly Old Skool Join Date: Nov 2001 Location: DFW Posts: 7,182	Re: RADAR questions? !!!!!!!!!!!!

January 28th, 2003, 08:46	#4
chunk75 Senior Member Join Date: Jul 2001 Location: FL Posts: 922	Re: RADAR questions? I remember one episode where Radar took a paternity test....I guess he had too much Grape Ne-Hi one night. Chunk

January 28th, 2003, 18:17	#5
CaliforniaSurfer Junior Member Join Date: Sep 2000 Location: SoCal Posts: 296	Re: RADAR questions? What the hell are you guys talking about?

January 28th, 2003, 18:57	#6
E_Dawg Moderator Join Date: Apr 2002 Location: chicago Posts: 4,232	Re: RADAR questions? I knew there was a MASH joke in here somewhere!!!!

January 28th, 2003, 20:01	#7
reaperman Junior Member Join Date: Aug 2001 Location: Seattle Posts: 45	Re: RADAR questions? RADAR. They're talking about RADAR. Look at the subject line. Sheesh!!

February 3rd, 2003, 09:19	#8
haree Junior Member Join Date: Dec 2001 Location: India Posts: 79	Re: RADAR questions? ok here goes..... I have been in atcs for quite sometime now... how do the radars track the expected altitude IAS etc.. of the aircraft,,,, General one: wouldnt it be bad if someone using a radar can estimate an A/cs settings;;;;

February 3rd, 2003, 09:33	#9
ready2fly Old Skool Join Date: Nov 2001 Location: DFW Posts: 7,182	Re: RADAR questions? haree - your Mode C transponder emits a signal that allows radar to "see" your altitude.

February 3rd, 2003, 18:18	#10
chunk75 Senior Member Join Date: Jul 2001 Location: FL Posts: 922	Re: RADAR questions? haree....can you clarify/amplify your question a bit...

February 4th, 2003, 18:07	#11
Eagle Banned Join Date: Oct 2000 Posts: 1,272	Re: RADAR questions? [ QUOTE ] how do the radars track the expected altitude IAS etc.. of the aircraft,,,, [/ QUOTE ] the expected altitudes are on the flight plan for each aircraft. the air speed is of no real importance (ICAS/TAS) as it is all relaitive to the other airplanes in the the line. you will be told to slow down or speed up to keep the spacing. you may get: Atc: Lear N34J, say airspeed. us: .78 atc: Lear N34J, maintain .7 in the decent. us: 4J or a decent climb at PIC descretion, once below the FLs it switches over to kts vs M.

February 4th, 2003, 20:31	#12
chunk75 Senior Member Join Date: Jul 2001 Location: FL Posts: 922	Re: RADAR questions? Also, RADAR doesn't give a lick about IAS/TAS, it only works in GS. Distance from antenna @ 'paint' A minus Distance from antenna @ 'paint'B divided by the difference in time in between paints = GS. Distance from antenna is determined by total time from pulse to return of echo divided by 12.36 microseconds (the time required for RADAR waves to travel one mile and back). Of course, you're talking about multiple paints in one sweep. A paint is one pulse and one echo. Chunk

February 5th, 2003, 08:35	#13
ready2fly Old Skool Join Date: Nov 2001 Location: DFW Posts: 7,182	Re: RADAR questions? [ QUOTE ] Distance from antenna @ 'paint' A minus Distance from antenna @ 'paint'B divided by the difference in time in between paints.. [/ QUOTE ] chunk, is it "paints" or "POINTS"?? Paint = like an image "painted" on the screen? Please advise. First I've heard that term. Thanks R2F

February 5th, 2003, 13:03	#14
chunk75 Senior Member Join Date: Jul 2001 Location: FL Posts: 922	Re: RADAR questions? A 'paint' is a unofficial, or technical slang, term for "illuminating" a target. Bouncing RADAR energy off of a target is called painting. Sometimes you'll hear the term "skin paint" which is getting a RADAR return unamplified by transponders. It is fairly uncommon for ATC RADAR to skin paint targets unless the aircraft has a large RADAR cross section (RCS) or they are close to the antenna. Approach RADAR's are more likely to get skin paints than Center RADAR because of the precision of the set. Center sets are long range EW (Early Warning) sets meant for max range at the expense of precision. Of course, precision is a relative term....center RADAR may have a resolution of .5nm while an approach set may have a range resolution of .01nm. These numbers are educated guesses...without the parameters of the set, I can't be certain. ATC RADAR relies on transponders to make targets noticable. Military RADAR, on the other hand, has to be powerful enough to rely on skin paints. An enemy target certainly isn't going to have a transponder on to boost the reply. Clear as mud? Chunk

February 5th, 2003, 14:41	#15
ready2fly Old Skool Join Date: Nov 2001 Location: DFW Posts: 7,182	Re: RADAR questions? [ QUOTE ] Clear as mud? [/ QUOTE ] Ah. Clear as mud. Thanks.

February 8th, 2003, 04:37	#16
haree Junior Member Join Date: Dec 2001 Location: India Posts: 79	Re: RADAR questions? Gee...Thanks That was few of the great replies...

February 8th, 2003, 06:14	#17
Eagle Banned Join Date: Oct 2000 Posts: 1,272	Re: RADAR questions? [ QUOTE ] Also, RADAR doesn't give a lick about IAS/TAS, it only works in GS. [/ QUOTE ] which is sorta interesting, figure you are doing 150kts ICAS, but your GS is 200kts. ATC sees 200kts and will make all assignments based on that, so you have a 50 kt tailwind, everyone does, that is headed your way. Many times I have heard. N1234 what kind of airplane are you? we are a baron sir, ATC.. huh, N1234, yeah winds. ( Assuming this guy is getting plowed with a headwind. the converse is also true I have heard Skyhawks begging ATC for a GS because they are in a 30-50kt tailwind. I don't know but can find out if anyone is really interested, if ACT keeps the head/tail winds in mind when you are given course changes.

February 16th, 2003, 22:40	#18
Mavmb Old Skool Join Date: Feb 2002 Location: Phoenix, AZ Posts: 2,169	Re: RADAR questions? I've got a question actually. Can ATC see the Transponders when you're on the ground waiting for takeoff? I'm assuming they can when you have it switched to altitude but I wasn't sure.

February 16th, 2003, 23:15	#19
mikek123 Junior Member Join Date: Jun 2002 Location: Gainesville, FL Posts: 112	Re: RADAR questions? [ QUOTE ] I've got a question actually. Can ATC see the Transponders when you're on the ground waiting for takeoff? I'm assuming they can when you have it switched to altitude but I wasn't sure. [/ QUOTE ] I belive it depends on where their radar is located and where you are on the airport. If the secondary radar antenna can't pick up your transponders signal then no, if there is nothing blocking the path between your transponder antenna and the radar than they can see you.

February 16th, 2003, 23:34	#20
E_Dawg Moderator Join Date: Apr 2002 Location: chicago Posts: 4,232	Re: RADAR questions? Yeah it absouletely depends on where the radar antenna is located; if you fly out over the ocean here in socal and descend below 500 - 1000 AGL you are virtually guarenteed to get a great big 'RADAR CONTACT LOST' from ATC. If they lose you at 500 feet over nothing but water I'd say it's a great bet they can't see you at all on the ground unless the antenna is actually on the field. ....which brings me to another question: where are the antennas usually located? ...airports? hilltops?

February 16th, 2003, 23:46	#21
drumminpilot Senior Member Join Date: Nov 2002 Location: Springdale, AR (XNA/RVS/ASG) Posts: 320	Re: RADAR questions? [ QUOTE ] where are the antennas usually located? ...airports? hilltops? [/ QUOTE ] One of the ones around here is about a mile or so off the airport on top of a hill, another one is on a tower at the airport. A question: Can ATC turn on a filter for traffic thats on the ground? I thought I remember one of the tower guys here telling me they could.....

February 16th, 2003, 23:47	#22
mikek123 Junior Member Join Date: Jun 2002 Location: Gainesville, FL Posts: 112	Re: RADAR questions? [ QUOTE ] which brings me to another question: where are the antennas usually located? [/ QUOTE ] I know alot of them are located at the airport usually on top of a building. In Daytona the radar is about 5 miles nw of the field. I guess it just depends on teh surroundings of the airport and how much room they have to put up a radar.

February 17th, 2003, 10:02	#23
reaperman Junior Member Join Date: Aug 2001 Location: Seattle Posts: 45	Re: RADAR questions? They can see you on the ground at OLS. "They" being the DEA and/or anyone else who's supposed to watch the Mexican border. If you are on the ground at OLS, about to taxi for takeoff, you are advised to have your transponder reporting altitude before you get moving. They don't need to worry about, or check out a contact that they've seen motionless or just coming off the ground at a friendly airport. But if they first notice you flying low in a small plane five miles from the border, they might have to take an interest in you.I don't know if the equipment is in the balloon tethered thirty miles East, or in planes that patrol the border.

February 17th, 2003, 10:33	#24
pavelump Senior Member Join Date: Jul 2002 Location: Chicago Posts: 790	Re: RADAR questions? When I landed in Valdosta, GA the ground/tower controller said, "Taxi to the ramp. And you can turn your transponder off." Ooops. Boy did I feel like a boob. Dave

February 17th, 2003, 12:38	#25
eodfe Junior Member Join Date: Apr 2002 Location: Centennial, Colorado Posts: 165	Re: RADAR questions? On a slow morning at APA (not very often) After runup I turned on my transponder and tower without me calling and saying ready for takeoff, cleared me for takeoff.

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