I remember it well! I was on a fast stretch of road, but keeping to the limit for that stretch. I came towards a village, where the speed limit dropped by 20mph. Obviously I slowed down, and continued to slow. The road curved round to the left and went downhill. All this within about 100 yards of the slow down sign. And guess who was waiting for me at the bottom of the bend? Yes, you guessed it, the boys in blue.

I was fined for being 4mph over the limit! Grr. It didn't seem right then, and it doesn't seem right now either. So was there anything I could have done to avoid this in justice?

Radar detectors are extremely effective for warning drivers that they are approaching a speed detection device that uses a radar system. The speed is calculated using the difference between the transmit frequency and receive frequency (also known as the Doppler shift). They are essentially microwave radio receivers, and as such, it is important that the detector you want can identify the radio waves emitted by the equipment used by the authorities.

Radar detectors come essentially in two flavours, corded or uncorded. The corded typically mounts to your windshield, and because of its location offers an aerial less-obstructed detection. Cordless is as the name suggests, and offers you portable convenience to have the unit located where you want. This also means that you can use the unit for different vehicles without having to resort to multiple units or fiddly removals or re-installs.

There are some important considerations when shopping for radar detectors. These include band detection, which allow a range of police radar devices to be detected, distance of detection, ability to send a jamming signal, and, of course, price. In addition to these concerns, anyone interested in purchasing a motorcycle radar detector should check that the detector comes with an ear jack, because you will have to rely on an aural signal for these devices to be effective for you.

Some radar detectors can be extremely expensive but finding a discount unit is relatively simple if you know where to look. One option for purchasing radar detectors cheaply is to search for wholesale electronic distributors who have their own retail outlets. You will need to ascertain from the manufacturer that the detector that you are trying to buy will work in your area, or has band detection available. The stockist should have information about the frequencies used by your local authorities as well, so try and find this out before you part with any hard earned cash. Bear in mind that the cost of a radar detector is far less than the cost of the speeding tickets that you may face - so or protect yourself, get a radar detector.

Used radar detectors prices are reasonable and sometimes negotiable. They can be purchased from owners, dealers, or from superstores. Try to buy used radar detectors directly from the owners if possible, as you are likely to get a better deal. In the case of superstores, used radar detector prices are not normally negotiable, though they are usually sold for a reasonable, predetermined price. However, it sometimes pays to ask for a cash deal and to have cash ready, just in case! Such companies recondition the units to sell as refurbished items. A specialty of refurbished radar detectors is that their prices are remarkably low and they provide the same benefit that a new radar detector offers.

A radar detector can be purchased via the Internet too, however, a local car audio store should be able to inform you of state laws that might limit purchasing options.