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Police have used a variety of equipment to check vehicle speed for many years, amphometers, digitectors (timing device) and of course the point of all this, radar speed equipment. To further complicate things police departments use various types of radar equipment made by different manufacturers, most equipment is of US origin, but lately there has been a trend towards European camera designs.
The problem arises in that most radar detectors are built either in the USA or Asia for use in the US, on long straight 12 lane highways, operating on their own US frequencies. This means that if you purchase a radar detector from overseas, it may not work well outside the USA. Most imported detectors won't give you protection against the latest K band camera radars currently being used, because the K band performance of 95% of these imported detectors is very, very poor.
Effective performance in New Zealand also depends on the quality of your detector. Detectors made for the US market have a much lower acceptable sensitivity level (range) than that which is needed for the effective long range detection of local radars. The latest Wideband detectors pick up substantially more interference from alarm systems, traffic lights and even other detectors. This increased false alarming is due to the wider range of frequencies needed for the US radars, and generally not needed outside the US.
To add to this issue, software to decrease false alarms, usually decreases radar performance. (range), The wider radar band coverage results in lower performance, the more frequencies you try to cover the lower the sensitivity (range).
Using POP mode turned on, on your radar detector, may decrease its overall performance! POP Mode radar is not used in New Zealand.
All US radar detectors are produced on an assembly line, and like cars, there are some real lemons out there or "Friday detectors". The performance of these production line units varies from good to bad to not functioning at all. Production and testing tollerances for products made in Asia, for the US market are ok. But for use outside the US, NZ and Australia, these wide tollerances usually spell performance problems.
Most lower cost units are usually engineered very differently inside, with subsequent lower radar performance. The lower performance units can have as little as 20% of the range of the top units. Creative Electronics filter out all the bad eggs, duds and lemons in our own test labs, to offer you the best of each manufacturer. We also modify or recalibrate some models to obtaine the optimum performance against New Zealand's radar systems.
Range usually up to 400 metres in moving or mobile use, 800 metres stationary. In stationary mode it works like a gun. It can be instant on, but still requires multiple readings to form an average which becomes your displayed speed. To-days Ka Band radar systems are very, very fast to aquire a target speed reading, so jumping on the brakes these days, is not an effective or safe option.
Single random pips on a good detector, like the latest Whistler top models, should be treated as a warning of a stationary or mobile radar operating in your area..
Unfortunately the majority of units are used in a mobile mode, with the transmitter OFF 90% of the time. To calculate your speed, the mobile radar needs to know the speed of the patrol car first, in order to determine your approaching speed. When an operator sights a potential target that may be above the limit, the operator releases the HOLD feature, unleashing the full power of the radar unit. Checking of the patrol speed is carried out by the main radar beam at the same time the closing speed oy your vehicles is checked. The radar unit deducts the ground speed of the patrol car (the lower Doppler shift) from the closing speed of the two vehicles, (the greater Doppler shift) the end result is then displayed on the radar as the true target speed (most times).
The mobile radar unit has a hand control button which allows the officer to "zap" your vehicle from the hold mode as your car comes into view, giving little time to slow. However, in order to operate as a mobile unit, it must check the ground speed each time, for each target. Each time a vehicle is checked the radar beam is transmitted at full power and can be detected by the top model very sensitive detectors, many kilometres away.
The Slant Doppler works by firing a narrow, low powered K or Ka radar band beam across the road at approximately 25 degrees. It uses the same frequency band as most of the other police radar in use. The major benefit to police is that it enables them to pick individual cars out in a line of traffic with reasonable accuracy. With normal radar, be it mobile or handgun, the beam fires down the road spreading as it goes. At around 400 metres from the radar unit, this beam spreads across up to 12 lanes of traffic, thus making it impossible to pick out individual cars in a line of traffic. Slant Beam Photo Radar overcomes this problem, it's pinpoint accurate, allowing it to be used effectively in multi-lane intercity roads.
Camera radar has been around since the early Eighties. Originally used mostly in Europe, these radars were positioned at the side of the road. Some were fixed to tripods, allowing for their relocation to various sites. Others were installed inside weatherproof boxes on top of long steel poles. They were positioned high above the road to avoid vandals spraying the camera lens with paint. These units were operated at fixed locations. Early camera radars operated on the X band.
In the late Eighties the new breed of high frequency cameras appeared on the market. Their higher operating frequency made these units physically smaller and more portable. The frequencies used by these roadside radars were K band. Besides the higher frequency, these units were engineered to have a very narrow beam, typically 2 degrees or about 6 feet wide. Many times narrower than normal radars.
All camera radars operate in the same manner. They are positioned at the side of the road, the radar beam is angled at approximately 25 degrees to the curb, the camera is also angled accordingly. This angle is to allow the radar to pick one vehicle out of the line of traffic. When a photo is taken, only one vehicle should be in the beam and in the photo. If the camera faced down the road, you would have a whole line of vehicles in the photo.
As the radar beam is angled across the road, it does not travel straight down the road. Besides this, the power output of the camera radars is reduced to avoid background vehicles from effecting readings of cars breaking the beam. This low power and angle give a radar range of around 10 metres, many times less than conventional radars.
Low power, less range and the 25 degree angle means that a detector has to be very good to detect this type of radar in time. Resultant pick up distance is from 30 metres on poor detectors, up to 300 metres on the best. Camera radars can be used to check the speed of approaching or receding vehicles, as is possible with other radar types. Some of the latest K band in car cameras monitor both directions of traffic at the same time. The photo taken is marked with an arrow to indicate the direction of the violation.
When detecting camera radars, the alarm on the 2-3 top detectors, will increase from slow beeps to very fast over a very short distance, because there is not much radar scatter to give distant early warning. When you are within 50 metres of the radar your detector should be alarming rapidly.
The actual process involved in determining a vehicle's speed is basically a simple one. It involves directing a beam of microwave energy at an approaching (or receding) target vehicle. A portion of this beam is reflected by the target vehicle and is received by the radar unit that originally transmitted the signal. The reflected signal is shifted in frequency by an amount proportional to the speed of the target vehicle. This is known as the Doppler Effect. The radar unit determines the target vehicle speed from the difference in frequency between the reflected signal and the original signal.
Currently there are three microwave frequencies that have been allocated by the FCC (Federal Communications Commission) and are used for traffic radar. In the 1980's there were some odd X band frequencies in Europe, but most, if not all have gone by now.
The main radar frequencies are:
X band: 10.525 GHz
K band: 24.150 GHz (NZ)
Ka band 33.00 -36.000 GHz (NZ)
Both X and K bands are well known to motorists who have travelled with radar detectors. Introduced first was X band radar which became common during the 1960's. In the mid 1970's the lower powered, more difficult to detect K band radar. In 1987, approval was given for use of radar on the third frequency.
Radar signals can be transmitted in a number of ways. They include:
This designation refers to radar systems that transmit a continuous, uninterrupted signal. These systems are commonly used in stationary K band camera radar.
Radar signals travel in a straight line and do not pass through earth. Consequently, police radar aimed at the crest of a hill cannot be received until you are at or near the crest. Warning time may be minimal, since a strong signal is not present until you are near the top of the hill. At this point you may be nearly in the police officer's line of sight.
This type of radar is more difficult to detect than radar using a continuous transmission because it is "off" until activated to measure the speed of a targeted vehicle. The high sensitivity provided by the best detector is critical for adequate early warning when Instant-On radar is used.
Police radar signals transmitted from behind your vehicle can be received when reflected by objects in front of you such as large signs, bridges and trucks. As you drive, the size and configuration of these objects are constantly changing causing the strength of any reflected radar signal received to vary. A consistent uninterrupted alarm can indicate that the patrol car is close behind.
If you are the target vehicle, an alarm caused by Instant-On radar will be strong and immediate. When encountered, your detector should respond with instant warning (rapid alarm). Many, if not all, of the latest digitally controlled radar detectors may take time to analyse this incoming signal. This can result in a dangerous delayed alert of up to 3 second!! This normally occurs at a distance of around 400 metres or less from the radar, whether it be either mobile or stationary.
If the police are using Instant-On/Pulsed radar, no signal is transmitted until visual contact has been made. For detection of this signal, you must rely on reflected signals from radar checks of traffic travelling ahead of you. If the highway traffic between your vehicle and the police radar source is heavy or large, this may block transmitted signals. The presence of several large trucks between you and the police radar could significantly reduce your warning time. Rain or humid weather conditions can absorb transmitted signals before they reach your vehicle, again reducing detection range.
Creative Electronics are unique amongst detector suppliers/producers and importers, in that we have 40 years experience in communications and electronics and 30 years hands on experience with the widest range of radar and laser products. We are able to offer detailed technical opinion on ALL detectors and advise on which product best suits your needs, driving requirements and hip pocket, without being stuck on one particular brand or type. The important point is that you will get the helpful advice you need when making such an important purchase decision.
You'll have to carefully examine where you drive and how fast you drive before deciding on a particular detector. There are some very well known brands available, but buying the latest model US made detector may give you at least half the range of your old unit.
If you would like to discuss your particular needs, or if you have any questions, e-mail us at sales@radar.co.nz
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