Index Home About Blog
From: John De Armond
Newsgroups: rec.outdoors.rv-travel
Subject: Re: Warning to Virginia Travelers
Date: Thu, 29 Mar 2001 05:13:06 -0500

dtblank3&& wrote:
> Greg Surratt wrote:
> > And some of the cops have
> > radar detector detectors just to make sure you aren't breaking THAT
> > particular law.
> Just how would a radar detector detector operate? I worked
> on radar and passive ECM some thirty years ago. I presumed
> that radar detectors functioned as a passive ECM. I'm not
> sure I grasp the concept of an RF receiver being detected.

It's simply a receiver tuned to the radar detector local oscillator,
for most brands 1 ghz below the radar band center frequency (10.520
and 24.5 ghz, X and K band respectively).  The better radar
detectors manufacturers quickly re-designed their units to use a
different IF frequency and to not emit much LO radiation.  This
results in a sort of highway darwinism - those drivers without a
clue who think they can plop a $99 radar detector on the dash and
speed with impunity get caught and occupy the fee grabbers while us
serious drivers with the good detectors are left unmolested.

One of my favorite tricks when I had to drive in Va was to take a
little Gunn oscillator, tune it to the detector detector frequency
and go out and annoy the pigs.  The Gunn oscillator had enough power
that I could light up Smokey from far away.  He'd either go nuts
looking for the source or pull over the nearest car.  With smokey
occupied with a bogey, the roads become safe again.

For anyone who wants to try this, one of the larger microwave motion
detectors for burglar alarms works well.  Simply bypass the pulse
driver to the Gunn, tune it to 9.520 GHZ (Measuring frequency with a
Letcher wire is close enough, as the detector detector is very broad
band.) and fire away.  Be sure to put a push button and an "ON" LED
on it and not a toggle switch so that you won't accidentally leave
it on and broadcast bear bait!


From: John De Armond
Newsgroups: rec.outdoors.rv-travel
Subject: Re: Warning to Virginia Travelers
Date: Fri, 30 Mar 2001 04:04:17 -0500

Greg Surratt wrote:

> The problem was that cops are not stupid (duh!).  Somehow, a truck
> running 80 mph just looks too obviously different from a truck that
> registers 55 on the radar gun.  I still got the ticket and I couldn't
> fight it using the old "show me how you calibrate the radar gun"
> argument - because the cop never said anything about his
> "malfunctioning radar" on the ticket or in the courtroom.

That's the bottom line.  When I play with a radar gun for a little
while, I learned that I can estimate the speed of an oncoming car
within a couple of MPH before I key the radar.  That ability doesn't
stick around - I can't just go out on the road and tell you how
every vehicle is going.  But with a radar gun to provide me
instantaneous and continuous feedback, I certainly can judge the
speed of the odd vehicle that my gun doesn't pick up for whatever
reason.  A cop who does this every day will surely be MUCH better
than I am.

The other thing that is important to realize is that once one learns
the characteristics of his radar gun, it is trivially easy to make
the gun register whatever reading is desired.  Panning the gun
across traffic while locking in the reading is one technique.
Having a filed down tuning fork is another.  Just saving the reading
from the last stop is yet another.  So even if you jam the cop, if
he really wants you, he will get you and he will be able to show you
the reading on the gun when you ask after having read one of those
"beat the system" books.  If he thinks you've jammed him or perhaps
he just doesn't like your looks, that reading might be enough to
make it reckless driving instead of simple speeding.

As long as we allow the cops to be the ones with the guns, anyone
who tries to go toe-to-toe with them will lose!  The best way to
drive fast is to learn to think like a cop, stay alert and if you
get stopped, be polite (so the cop won't remember in court how big
an asshole you were) and then either pay the tax on driving fast or
fight it in court where you do have a chance.

From: John De Armond
Newsgroups: rec.outdoors.rv-travel
Subject: Re: Warning to Virginia Travelers
Date: Sat, 31 Mar 2001 03:06:24 -0500

JPSJPS wrote:
> John, I hope this is not lost in the crap.
> Nice collection on your site!!
> Question please:  What kind of radar detector do you recommend? Tickets
> here in California plus insurance increases offset a few hundred bucks
> for a detector. Of course, I need enough range and wide enough antenna
> pattern to detect an "instant on" radar on the guy way in front of me. I
> would not mind buying two different brands if necessary. I try not to
> intentionally speed since it is too expensive, but sometimes it happens.

There's really only one detector to have for the serious speeder -
Valentine 1.  Other brands will occasionally score equal to or maybe
even a little better than the V-1 on one feature or another but the
V-1 is the best package there is - pretty much the cost-is-no-object

Back during the magazine days I invented this little game I called
Trolling for Tail Lights.  Involves a radar gun and the illumination
of a passing speeder and then scoring his response.  The radar beam,
also known as the Tractor Beam and the Negative Velocity Insertion
Vector, would stimulate some very interesting responses from
speeders.  Everything up to and including hopping the median and
speeding off in the other direction :-)  That is, except most V-1
owners.  The V-1 indicates the band, the field strength and
DIRECTION of the radar.  Since pacing radar didn't then yet exist,
if the driver got a bogey from the rear, he could do a quick mirror
check and continue on.  In later versions of the game I even awarded
bonus points for stimulating responses from V-1 owners.  Anyway, I
published the game in the magazine.  Only thing I've ever done that
got me death threats :-)

> Are one of those guys in the bushes that put 70 mph Doppler on your Gunn
> oscillator to get some local dignitaries doing 30 mph nailed on radar?

I know nothing.....  And I can't say a word about my 10 watt 10 ghz
traveling wave tube transmitter....


From: John De Armond
Newsgroups: rec.outdoors.rv-travel
Subject: Re: Warning to Virginia Travelers
Date: Sat, 31 Mar 2001 14:59:59 -0500

JPSJPS wrote:

> Thanks John,  Am gonna get a Valentine 1 then. Any suggetions for a
> source? On-line store is fine with me.
> John

They only sell direct.  Grab an issue of Car & Driver (or search the
web) for the 800 number.


From: John De Armond
Newsgroups: rec.outdoors.rv-travel
Subject: Re: Warning to Virginia Travelers
Date: Wed, 11 Apr 2001 14:04:49 -0400

Joe Hoechst wrote:

> Thay don't smash the radar detector.  That would be destroying
> evidence.  I have been pulled over and caught with a radar detector in
> Virginia.  He asked to see it, I showd it to him.  He called it in to
> make sure it was not stolen.  Then he gave it back.  And these are the
> officers words "It's not illegal to own it, you just can't use it." (in
> Virgina)

The way it was written up in the National Motorist League, the cop
would give the driver the option of either destroying the detector
or getting written up.  Usually the driver did the stomping.  That
was back in the fiscal feeding frenzy of the 55 mph debacle.  No
doubt they've mellowed a bit in Va now like they have here.  In Tn,
the staties are practically a non-issue as long as you stay under 80
on the interstate.  Looks like they're concentrating on the 2 lane
roads where they should have been all along.


From: John De Armond
Newsgroups: rec.outdoors.rv-travel
Subject: Re: Speed trap listing
Date: Tue, 29 Mar 2005 22:03:50 -0500
Message-ID: <>

On Wed, 30 Mar 2005 00:18:01 GMT, Ken Bosch <xjobfpu@rneguyvax.arg>

>>They are illegal in VA - Cops have detectors and will ticket you.
>Radar detectors are passive receivers. They can't be detected that I
>know of other than by sight.

Sure they can be.  The radar detector detectors listen for the local
oscillator in the radar detector.  Almost all radar detectors use a 1
ghz IF frequency so one simply need listen 1 ghz away from center
frequency of each band.  Any detector that incorporates the mixer
diode in the waveguide (almost all of 'em) and doesn't employ a good
circulator (again, almost all of 'em) emits a LO signal that is almost
as strong as the radar, particularly the newer low power radars.

Some of the high end detectors (Valentine, high end Escort and a
couple others that I can't recall the names of) have changed their
architectures to use double conversion IFs and low leakage LOs.  These
same detectors contain radar detector detector detectors.  Whew!  And
in turn the enemy is making detectors for these.

The enemy is fighting a losing game, though.  The detector detector
has to be manipulated manually to pinpoint which vehicle the emissions
are coming from.  Meanwhile the alert driver has detected the detector
and turned his unit off.  Un-alert drivers serve as decoys for the
rest of us :-)

The really funny thing is, these fee grabbers spend the big bux for
the frequency agile pulse mode instant on radars to hide the speed
trap until it's too late for the victims and then they turn around and
leave the detector detector on all the time, radiating a CW (that
nasty old local oscillator again) signal that yells "speed trap" for
miles around to anyone with the proper detector.


Index Home About Blog