Airport Radar interference?

[compprof]

What is the name of your state?What is the name of your state? Ohio
I was issued a ticket for going 58 in a 35 mph zone, directly in front of a local airport. I had just made a left turn from a red light and only driven less than 2/10 of a mile when the local cop pulled me over. I was absolutely shocked when he issued this ticket. There is NO WAY I was going that fast. I know that his radar was incorrect. Does anyone know if there have been any cases of airport radar interference. (He was parked in the parking lot next to the control tower - seriously less than 100 ft away from it).

Help! I am innocent!

 

[Dash8Driver]

Most airport's radars are not on the field. The ones that are, are usually direction specific, meaing they only sweep the area directly in front of the runways for precision monitoring.

To answer your question, an airport type radar would not interfere with a police radar since they are different wavelengths. Sorry

D8D

 

[JETX]

Most airport's radars are not on the field. The ones that are, are usually direction specific, meaing they only sweep the area directly in front of the runways for precision monitoring.

That is not true. Airport radars (at least everyone I have seen) are 360 degree sweeps. This is so that they can see ANY aircraft in or crossing the range of the radar or their TCA (Terminal Control Area).

To answer your question, an airport type radar would not interfere with a police radar since they are different wavelengths.

That is correct.

Also, airport radars are NOT mounted on or near the control tower, but usually in a remote area of the airport property or even off-property.

 

[Dash8Driver]

That is not true. Airport radars (at least everyone I have seen) are 360 degree sweeps. This is so that they can see ANY aircraft in or crossing the range of the radar or their TCA (Terminal Control Area).

Sorry, PAR (precision approach monitoring radar) only sweeps about 10 degrees in front of the runway allowing for a faster sweep thus faster update as to aircraft position while performing simultaneous close parrallel approaches. This type of radar is limited and only at airports with control towers, parallel runways less than 4300 feet apart, and ILS approaches AND if the the simultanous approaches are authorized.

Also a radar cannot see every aircraft in its range since most, if not all, radars are slightly tilted up to allow for a farther range to see aircraft at higher altitudes thuse leaving the radar blind close to the antenna and at low altitudes. So even if the radar was on the field it most likely is not emitting any energy that could be picked up by the police radar.

check out this link for a techy version http://www.radarpages.co.uk/mob/navaids/par/par1.htm

D8D

 

[JETX]

Sorry, PAR (precision approach monitoring radar) only sweeps about 10 degrees in front of the runway allowing for a faster sweep thus faster update as to aircraft position while performing simultaneous close parrallel approaches.

Yes, there are several different types of radar and radio guides used in aircraft, however, your statement that "Most airport's radars are not on the field. The ones that are, are usually direction specific, meaing they only sweep the area directly in front of the runways for precision monitoring." is not correct. Air traffic control is done using 'sweep radar' where the beam is sent in a rotating pattern throughout the full 360 degree sweep.
Airports use other types of radars also, some are:
- "Search radars" scan a wide area with pulses of short radio waves. They usually scan the area two to four times a minute. The waves are usually less than a meter long. Ships and planes are metal, and reflect radio waves. The radar measures the distance to the reflector by measuring the time from emission of a pulse to reception, and dividing by the speed of light. To be accepted, the received pulse has to lie within a period of time called the range gate. The radar determines the direction because the short radio waves behave like a search light when emitted from the reflector of the radar set's antenna.
- "Weather radars" can resemble search radars. These radar use radio waves with horizontal, dual (horizontal and vertical), or circular polarization. The frequency selection of weather radar is a performance compromise between precipitation reflectivity and attenuation due to atmospheric water vapor. Some weather radar uses doppler to measure wind speeds.
- "Navigational radars" resemble search radar, but use very short waves that reflect from earth and stone. They are common on commercial ships and long-distance commercial aircraft.
- Air traffic control uses Primary and Secondary Radars
- Primary radar is a "classical" radar which reflects all kind of echoes, including aircraft and clouds.
- Secondary radar emit pulses and listen for special answer of digital data emitted by an Aircraft Transponder as an answer. Transponders emit different kind of data like a 4 octal ID (mode A), the onboard calculated altitude (mode C) or the Callsign (not the flight number) (mode S). Military use transponders to establish the nationality and intention of an aircraft, so that air defenses can identify possibly hostile radar returns.

 

[Dash8Driver]

Yes, there are several different types of radar and radio guides used in aircraft, however, your statement that "Most airport's radars are not on the field. The ones that are, are usually direction specific, meaing they only sweep the area directly in front of the runways for precision monitoring." is not correct. Air traffic control is done using 'sweep radar' where the beam is sent in a rotating pattern throughout the full 360 degree sweep.

360 degree sweeps are only needed when you need to see 360 degrees. To keep the scan rate fast thes PAR radars only scan 10 - 20 degrees and provide the controller with a "real time" picture of what is going on.

Airports use other types of radars also, some are:
- "Search radars" scan a wide area with pulses of short radio waves. They usually scan the area two to four times a minute. The waves are usually less than a meter long. Ships and planes are metal, and reflect radio waves. The radar measures the distance to the reflector by measuring the time from emission of a pulse to reception, and dividing by the speed of light. To be accepted, the received pulse has to lie within a period of time called the range gate. The radar determines the direction because the short radio waves behave like a search light when emitted from the reflector of the radar set's antenna.
- "Weather radars" can resemble search radars. These radar use radio waves with horizontal, dual (horizontal and vertical), or circular polarization. The frequency selection of weather radar is a performance compromise between precipitation reflectivity and attenuation due to atmospheric water vapor. Some weather radar uses doppler to measure wind speeds.
- "Navigational radars" resemble search radar, but use very short waves that reflect from earth and stone. They are common on commercial ships and long-distance commercial aircraft.
- Air traffic control uses Primary and Secondary Radars
- Primary radar is a "classical" radar which reflects all kind of echoes, including aircraft and clouds.
- Secondary radar emit pulses and listen for special answer of digital data emitted by an Aircraft Transponder as an answer. Transponders emit different kind of data like a 4 octal ID (mode A), the onboard calculated altitude (mode C) or the Callsign (not the flight number) (mode S). Military use transponders to establish the nationality and intention of an aircraft, so that air defenses can identify possibly hostile radar returns.

Yes you are right on the types or radars, but most of these radars are not on the field since the airport is rarely the center of the radar image. Most ARTCC (Air traffic control centers) radar are a congolmorate of multiple radar sites spread through out the centers airspace area. Aproach control radars are usuall at the primary airport for the city. Example: Minneapolis Internation Airport (KMSP) has the approach radar on top of the control tower, but that radar also serves 12-15 smaller airports around the area. Now Grand Forks International (KGFK) radar is based at the Red River Air Base (KRDR) about 15 miles to the west, which also serves 10 or so smaller airports in the area.

Just to clarify, mode A reports the squawk code or the 4 number code (1 - 7) and mode C reports the pressure altitude the aircraft is flying at and the squawk code. ATC can assign a callsign to a squawk code, so my squawk code might be 1234, but ATC could assign my flight number, 4456 to that code and it would show up on his scope as XX4456, the XX being the two letter ident for the airline ie UsAir being US4456. Mode S now enables to aircraft with TCAS (Traffic Collision Avoidance System) to "talk" to each other and come up with diversion solutions should collision between the two aircraft be immenint. Now if only one aircraft has mode S and TCAS and another only has a mode C only the aircraft with Mode S will recieve traffic warnings and solutions to collisions. (I've seen and heard way too many of these flying along the East Coast, stupid GA peole flying at IFR altitudes on VFR plans )

Weather radar can come in two fold, doppler or simple energy return. Doppler simply measures wind speeds to and away from the antenna thus showing the "strength" of the storm. Energy return radars show precipitation and show the intensity of a storm by showing the amount of rainfall/precipitation. Some Air Traffic control radars can show weather and are a great help especially during embedded thunderstorm days. Most aircraft have energy return radars that are usually grossly under powered, 10 to 15 watts. This only lets us see about 200 miles and then as the storms becoming more and more intense we can't "see" on the other side of the storm because the radar runs out of energy.

Another cool thing with Mode S is now General Aviation (GA) can have a "poor mans" TCAS. With recent upgrades to some radar sites, GA aircraft with Mode S transponders can send and recieve signals from the ground radar site and display other aircraft in the area with at least mode C transponders. I thought it was cool until I turned it on one day and realized just how close together we were flying to other people in the practice areas .

D8D

 

[lwpat]

I now know more than I really wanted to know.

 

[Dash8Driver]

Scary isn't it

D8D