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Since
all radar detectors are simply radios tuned to the microwave
frequencies used by traffic radar, they automatically sound
an alarm whenever they encounter signals on those frequencies.
The problem is, other devices that are
not radar are also operating on radar frequencies. A detecting
radio must respond to them, too. Every response indicates
a threat, a bogey. Only your judgment can distinguish
actual radar warnings from the non-radar alarms. Let's
start with the basics:
- X
band: A catch-all band, still used regularly in some
areas by traffic radar, but heavily populated by sensors
for supermarket automatic doors and other nuisance signals.
In shopping areas, expect door sensors. But know the
territory. Unless you’re sure that X band is
not used locally for radar, stay alert until you’ve
identified the bogey.
- K
band: Maybe radar, maybe not. Supermarket door sensors
operating on K have recently begun corrupting this formerly
reliable warning of radar. Another non-radar source—cheapie
radar detectors that pollute by transmitting on K.
Here
are a few clues for spotting offending radar detectors.
You may get a brief K warning just as you meet an
oncoming car. Or a lingering K, nearly constant strength,
as you move with traffic. Big hint: a direction change
on the Radar Locator as you pass another car. Look
for a detector in the windshield. But stay alert until
you know for sure.
- Ka
band: Watch out! Most of the new-tech radars operate
on Ka. Expect some contamination from cheapie radar
detectors, just as with K (clues above also apply
to Ka). Do not dismiss Ka alerts until you’ve
positively IDed the source.
How
To Identify Bogeys: Look first at the Radar Locator.
If it points to the side, the bogey is non-threatening—radar
can't get you from the side. If the Locator points ahead
or behind, try for visual identification. And when the Locator
changes from Ahead to Beside and then Behind, you can be
sure the bogey is safely behind you. Check the Bogey Counter, because many
non-radar devices occur in multiples. For example, most
microwave door sensors have at least two transmitters
(for In and Out). Often such an installation will have
multiple doors too, so there will be many transmitters.
When you see two or more on the Bogey Counter, and particularly
when you see it counting up quickly to four or more, you've
likely found a nest of door sensors.
Burglar-alarm microwave sensors are often
multiples too, because a single transmitter is not enough
to safeguard an entire building. But microwaves from alarms
are less likely to leak out of buildings. So alarms may
appear singly or in low multiples.
Single bogeys must be regarded as threats
until you see them, or put them safely behind you. |
