Radar Jamming

[Jim Thompson]

On Thu, 14 Apr 2005 11:01:36 -0400, Keith Williams <krw@att.bizzzz>
wrote:

In article <425E1625.D443DDA1@hotmail.com>,
rabbitsfriendsandrelations@hotmail.com says...
[snip]

It's a great way of earning extra revenue for the authorities though.

Bingo! Vermont passed a law so virtually all "revenue" goes to the
state. The result is that localities aren't so interested in radar
traps. ;-)

Politicians worship the god of revenue. Take that away and there's no
interest.

I like the concept of all revenue going to the state. I think I'll
prime some legislators with the idea ;-)

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[martin griffith]

On Thu, 14 Apr 2005 08:25:13 -0700, in sci.electronics.design Jim
Thompson <thegreatone@example.com> wrote:

Politicians worship the god of revenue. Take that away and there's no
interest.

My brother was working in Damascus for a few years, the water supply
was always a problem.

"Why cant they fix it" I asked him

"Because the politicians cant figure out how to make money from it"
was his reply



martin

"Wales is a big welsh-shaped rain collection device"

 

[A.Nonny Mouse]

Andy wrote:

But it occurred to me, why not use the same technique for a radar
jammer. Whatever frequency hits the receive antenna is amplified and
modulated with a 2V/lambda doppler OOK signal, and the radar gun
would register a Volkswagen going at 250 mph, or some such, and
NOTHING is transmitted until a radar gun signal hits the tag.....
Seemed like a great idea.

I never tested it on a radar gun, but I am sure the technique is
worth considering.....

These days, most stationary speed traps in my area use laser guns. About
the only place radar is still used is in patrol cars while in motion.

I've wondered about the effectiveness of mounting a set of corner
reflectors on a spinning disk (inside a radar-transparent enclosure, of
course). You could increase or decrease your reported speed by choosing
the direction and speed you spin the disk. This is completely passive,
just like your idea, but has the advantage of being low-tech.

I'm not an RF guy but I assume that a fairly small intentional reflector
can produce a reflection that is larger than the backscatter from the
car body. The spinning will also impart some sort of sinusoidal
variation to the reflected signal frequency, but I don't know if this is
a good or bad thing. The widget could be mounted on the roof (not so
good for cosmetics), or possibly inside the vehicle (much better).

Does this idea have any merit?

 

[Mac]

On Thu, 14 Apr 2005 17:54:40 +0800, Harvz wrote:

[top-post moved down]

"Mac" <foo@bar.net> wrote in message
newsan.2005.04.14.03.35.49.257573@bar.net...
On Wed, 13 Apr 2005 21:05:25 +0800, Harvz wrote:

Has anybody actually made a working radar jammer themself?

No, but I have thought about how you would make a spoofer.

You would have separate receive and transmit antennas. The receive antenna
would be fed to a mixer. The other mixer input would be a Doppler shift
frequency you generate according to vehicle speed (that is, it is the
exact amount of Doppler shift you need to send your detected speed down
to 0. Then you low pass filter the mixer output to select the lower
sideband, and send the output of the low pass filter to the transmit
antenna.

In reality, you probably couldn't design a low-pass filter with a sharp
enough cutoff, so you would have to get the lower sideband some other
way. The basic idea is to use a Single Side Band Suppressed Carrier type
of modulation. I'm not a microwave guru, so I would have to go read up on
this stuff a little more before I could say whether this would really
work.

And it might be hard to provide sufficient isolation between the transmit
and receive antennas. The system might run off chasing its tail if the
transmit is allowed to feed back into the receive.

Anyway, it's easy to sketch a system out. The devil is in the details.
;-)

--Mac

Well thanx Mac,
thats all i wanted was some ideas and to see if anyone
had tried it. Not all the BS from these F_cking yanks and their guns, they
can't leave em out of one conversation.....DEPENDENCY!!!!! hehehehehe

I am a "Yank." My views on guns, the 2nd amendment and what it means for
us here in the USA would probably not please you.

I have not found it fruitful to talk about such matters in this newsgroup.
I only mention it because you seem to be implicitly enlisting me as an
ally, and I don't particularly want to be your ally.

;-)

--Mac

 

[Mac]

On Thu, 14 Apr 2005 21:28:45 +0000, A.Nonny Mouse wrote:

Andy wrote:

But it occurred to me, why not use the same technique for a radar
jammer. Whatever frequency hits the receive antenna is amplified and
modulated with a 2V/lambda doppler OOK signal, and the radar gun
would register a Volkswagen going at 250 mph, or some such, and
NOTHING is transmitted until a radar gun signal hits the tag.....
Seemed like a great idea.

I never tested it on a radar gun, but I am sure the technique is
worth considering.....

These days, most stationary speed traps in my area use laser guns. About
the only place radar is still used is in patrol cars while in motion.

I've wondered about the effectiveness of mounting a set of corner
reflectors on a spinning disk (inside a radar-transparent enclosure, of
course). You could increase or decrease your reported speed by choosing
the direction and speed you spin the disk. This is completely passive,
just like your idea, but has the advantage of being low-tech.

I'm not an RF guy but I assume that a fairly small intentional reflector
can produce a reflection that is larger than the backscatter from the
car body. The spinning will also impart some sort of sinusoidal
variation to the reflected signal frequency, but I don't know if this is
a good or bad thing. The widget could be mounted on the roof (not so
good for cosmetics), or possibly inside the vehicle (much better).

Does this idea have any merit?

Not as a practical solution. I think the corner reflectors have to be
fairly large (more than a wavelength) to overwhelm the return from the
car.

But I have no doubt whatsoever that it will work if the spinning disk is
large enough. Say as wide or a little wider than the car, for example.

A similar idea is to somehow put the reflectors on the wheels of
the car. If you could make the bottom half of the wheel much more
reflective than the rest of the car (including the top half of the
wheel: obviously this would only work for one direction, forward or back)
then radar guns might just not work on your car. But in reality, I don't
think you could accomplish this and still have a practical wheel.

--Mac

 

[Ken Taylor]

"Mac" <foo@bar.net> wrote in message
newsan.2005.04.15.03.54.18.850692@bar.net...

On Thu, 14 Apr 2005 21:28:45 +0000, A.Nonny Mouse wrote:

Andy wrote:

But it occurred to me, why not use the same technique for a radar
jammer. Whatever frequency hits the receive antenna is amplified and
modulated with a 2V/lambda doppler OOK signal, and the radar gun
would register a Volkswagen going at 250 mph, or some such, and
NOTHING is transmitted until a radar gun signal hits the tag.....
Seemed like a great idea.

I never tested it on a radar gun, but I am sure the technique is
worth considering.....

These days, most stationary speed traps in my area use laser guns. About
the only place radar is still used is in patrol cars while in motion.

I've wondered about the effectiveness of mounting a set of corner
reflectors on a spinning disk (inside a radar-transparent enclosure, of
course). You could increase or decrease your reported speed by choosing
the direction and speed you spin the disk. This is completely passive,
just like your idea, but has the advantage of being low-tech.

I'm not an RF guy but I assume that a fairly small intentional reflector
can produce a reflection that is larger than the backscatter from the
car body. The spinning will also impart some sort of sinusoidal
variation to the reflected signal frequency, but I don't know if this is
a good or bad thing. The widget could be mounted on the roof (not so
good for cosmetics), or possibly inside the vehicle (much better).

Does this idea have any merit?

Not as a practical solution. I think the corner reflectors have to be
fairly large (more than a wavelength) to overwhelm the return from the
car.

But I have no doubt whatsoever that it will work if the spinning disk is
large enough. Say as wide or a little wider than the car, for example.

A similar idea is to somehow put the reflectors on the wheels of
the car. If you could make the bottom half of the wheel much more
reflective than the rest of the car (including the top half of the
wheel: obviously this would only work for one direction, forward or back)
then radar guns might just not work on your car. But in reality, I don't
think you could accomplish this and still have a practical wheel.

--Mac

You can spoof the police radar by sitting behind a very large, slow moving

truck. At least it seems to work, I've never been stopped for speeding when
using this evasive technique.

Ken

 

[Jim Thompson]

On Fri, 15 Apr 2005 16:36:00 +1200, "Ken Taylor" <ken123@xtra.co.nz>
wrote:

"Mac" <foo@bar.net> wrote in message
newsan.2005.04.15.03.54.18.850692@bar.net...
[snip]
A similar idea is to somehow put the reflectors on the wheels of
the car. If you could make the bottom half of the wheel much more
reflective than the rest of the car (including the top half of the
wheel: obviously this would only work for one direction, forward or back)
then radar guns might just not work on your car. But in reality, I don't
think you could accomplish this and still have a practical wheel.

--Mac

You can spoof the police radar by sitting behind a very large, slow moving
truck. At least it seems to work, I've never been stopped for speeding when
using this evasive technique.

Ken

I've found, through experiment, that sufficiently rapid deceleration
renders the police radar non-reading ;-)

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Keith Williams]

In article <lhhu51tmh0o6pt3cfukb6b7jail7l2gsqn@4ax.com>,
thegreatone@example.com says...

On Fri, 15 Apr 2005 16:36:00 +1200, "Ken Taylor" <ken123@xtra.co.nz
wrote:

"Mac" <foo@bar.net> wrote in message
newsan.2005.04.15.03.54.18.850692@bar.net...
[snip]
A similar idea is to somehow put the reflectors on the wheels of
the car. If you could make the bottom half of the wheel much more
reflective than the rest of the car (including the top half of the
wheel: obviously this would only work for one direction, forward or back)
then radar guns might just not work on your car. But in reality, I don't
think you could accomplish this and still have a practical wheel.

--Mac

You can spoof the police radar by sitting behind a very large, slow moving
truck. At least it seems to work, I've never been stopped for speeding when
using this evasive technique.

Ken


I've found, through experiment, that sufficiently rapid deceleration
renders the police radar non-reading ;-)

A friend used this technique on a 'cycle to beat a 90-in-a-35 rap. THe
RADAR wouldn't lock, but the cop eyed him. Instead of a 55-over ticket
(likely a felony), he got a <15 over, since the cop was using the RADAR
and it showed nothing.

--
Keith

 

[Jim Thompson]

On Fri, 15 Apr 2005 01:04:07 -0400, Keith Williams <krw@att.bizzzz>
wrote:

In article <lhhu51tmh0o6pt3cfukb6b7jail7l2gsqn@4ax.com>,
thegreatone@example.com says...
On Fri, 15 Apr 2005 16:36:00 +1200, "Ken Taylor" <ken123@xtra.co.nz
wrote:

"Mac" <foo@bar.net> wrote in message
newsan.2005.04.15.03.54.18.850692@bar.net...
[snip]
A similar idea is to somehow put the reflectors on the wheels of
the car. If you could make the bottom half of the wheel much more
reflective than the rest of the car (including the top half of the
wheel: obviously this would only work for one direction, forward or back)
then radar guns might just not work on your car. But in reality, I don't
think you could accomplish this and still have a practical wheel.

--Mac

You can spoof the police radar by sitting behind a very large, slow moving
truck. At least it seems to work, I've never been stopped for speeding when
using this evasive technique.

Ken


I've found, through experiment, that sufficiently rapid deceleration
renders the police radar non-reading ;-)

A friend used this technique on a 'cycle to beat a 90-in-a-35 rap. THe
RADAR wouldn't lock, but the cop eyed him. Instead of a 55-over ticket
(likely a felony), he got a <15 over, since the cop was using the RADAR
and it showed nothing.

I got an "energy ticket"... back in the Carter double-nickel days ;-)

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Pooh Bear]

Harvz wrote:

Has anybody actually made a working radar jammer themself?

Since radar speed traps are moving to other technologies ( the most
insidious being high definition optical scanning that reads your
registation plate and calculates your speed at the same time ) this is
only likely to be a temporary palliative.

Best advice ( dunno if they're available over there yet ) is to get a
GPS based device that compares your location with all known speed trap
sites. Since this is marketed as a safety enhancement product it hasn't
been banned.


Graham

 

[Barry Lennox]

On 14 Apr 2005 15:52:56 -0700, "Andy" <andysharpe@juno.com> wrote:

That sounds like a neat thing to try. I would mount three mirrors as

a corner reflector, which essentially BEAM the laser signal back to the

source --- very directional , and a very high reflection coefficient.
Then, if the assembly was mounted on a bigass speaker assembly, which
was modulated with an audio tone ( 2V/lamba again) it should do the
same
as the backscatter tag I have mentioned before, only at light
frequencies.
I would really like to try this --- the three mirror technique is
used
for enhanced reflectors for sailboats - to give a bigger radar return-
only
they are made of metal to be useful to radar signals....

I think you are onto a good idea, but a three corner reflector will
give
a much better RCS return since this arrangement is like a beam
reflector.
You gotta try it out with a laser lever or pointer to see how well it
works, but the return is very high......

If you, or anyone else, would like to BS about this, I would be
please to correspond.

Andy at andysharpe@juno.com

Subject to some details being worked out, this has a lot of promise
and I have been meaning to try this. Trouble is, I reckon that road
trials (without a friendly and co-operative cop) are high-risk
potentially-expensive activities!!!!

From a number of radar flight tests I did a few years back, it always
amazed me how much return you get off a tiny little retro-reflector.
So, I'd imagine that small one will give a more solid return than most
autos.

The problem with mechanically modulating it would be the up and down
Doppler shift as the speaker gives it a + and - component. I think the
processing in the radar gun would get confused, or ignore it, or
something equally unsatisfactory.

And I don't know how sensitive the radar gun would be to AM or OOK, I
think it might ignore those and just deal with the FM/Doppler. If they
are sensitive to AM, the easy way would be to arrange a diode across a
dipole and switch it with the appropriate audio freq you want
presented to the cop. And maybe if you just did modulate it with
audio, the radar gun would see that sideband as the one to be
processed (incorrectly of course)


Barry Lennox

 

[John Woodgate]

I read in sci.electronics.design that Barry Lennox
<rianz.15.barryl@neverbox.com> wrote (in
<pquu5157rm6sri4upkvdva2km7bt02ov44@4ax.com&gt about 'Radar Jamming', on
Fri, 15 Apr 2005:

And I don't know how sensitive the radar gun would be to AM or OOK,

The British ones have a low-pass filter with a cut-off below 1 Hz, so
anything vibrating just doesn't register.
--
Regards, John Woodgate, OOO - Own Opinions Only.
There are two sides to every question, except
'What is a Moebius strip?'
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[Rich Grise]

On Fri, 15 Apr 2005 20:41:59 +1200, Barry Lennox wrote:

Subject to some details being worked out, this has a lot of promise
and I have been meaning to try this. Trouble is, I reckon that road
trials (without a friendly and co-operative cop) are high-risk
potentially-expensive activities!!!!

From a number of radar flight tests I did a few years back, it always
amazed me how much return you get off a tiny little retro-reflector.
So, I'd imagine that small one will give a more solid return than most
autos.

The problem with mechanically modulating it would be the up and down
Doppler shift as the speaker gives it a + and - component. I think the
processing in the radar gun would get confused, or ignore it, or
something equally unsatisfactory.

If you want to fool doppler, just use a TWT amp transponder, but
serrodyne modulate it.

Good Luck!
Rich

 

[Richard the Dreaded Liber]

On Thu, 14 Apr 2005 22:23:32 -0700, Jim Thompson wrote:

I got an "energy ticket"... back in the Carter double-nickel days ;-)

Let's not blame Jimmy for what was actually an Imperial Edict from your
fair-haired proto-neocon, Richard M. Nixon, AKA Trickee Dickee.

Thanks,
Rich

 

[Bob Stephens]

On Fri, 15 Apr 2005 17:21:13 GMT, Richard the Dreaded Libertarian wrote:

On Thu, 14 Apr 2005 22:23:32 -0700, Jim Thompson wrote:

I got an "energy ticket"... back in the Carter double-nickel days ;-)

Let's not blame Jimmy for what was actually an Imperial Edict from your
fair-haired proto-neocon, Richard M. Nixon, AKA Trickee Dickee.

Thanks,
Rich

I thought the '55 saves lives' campaign was bogus, but I still kind of like
the idea - if you must arbitrarily set the limit at 55 - of anything
between 55 and 75 being an energy offence as opposed to an insurance hiking
moving violation and crime against humanity. Sort of like the pay to
pollute gambit for industry.


Bob

 

[Jim Thompson]

On Fri, 15 Apr 2005 10:37:02 -0700, Bob Stephens <roberts@dcxchol.com>
wrote:

On Fri, 15 Apr 2005 17:21:13 GMT, Richard the Dreaded Libertarian wrote:

On Thu, 14 Apr 2005 22:23:32 -0700, Jim Thompson wrote:

I got an "energy ticket"... back in the Carter double-nickel days ;-)

Let's not blame Jimmy for what was actually an Imperial Edict from your
fair-haired proto-neocon, Richard M. Nixon, AKA Trickee Dickee.

Thanks,
Rich

I thought the '55 saves lives' campaign was bogus, but I still kind of like
the idea - if you must arbitrarily set the limit at 55 - of anything
between 55 and 75 being an energy offence as opposed to an insurance hiking
moving violation and crime against humanity. Sort of like the pay to
pollute gambit for industry.


Bob

I ran across an article just a few days ago debunking '55 saves
lives', I'll see if I can locate it again.

We (in Arizona) are about to raise all freeway speed limits to 75,
which is the "granny" speed around here.

I understand they've been nailing people right and left doing 110+ on
Loop 101 ;-)

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Bob Stephens]

On Fri, 15 Apr 2005 11:20:14 -0700, Jim Thompson wrote:

On Fri, 15 Apr 2005 10:37:02 -0700, Bob Stephens <roberts@dcxchol.com
wrote:

On Fri, 15 Apr 2005 17:21:13 GMT, Richard the Dreaded Libertarian wrote:

On Thu, 14 Apr 2005 22:23:32 -0700, Jim Thompson wrote:

I got an "energy ticket"... back in the Carter double-nickel days ;-)

Let's not blame Jimmy for what was actually an Imperial Edict from your
fair-haired proto-neocon, Richard M. Nixon, AKA Trickee Dickee.

Thanks,
Rich

I thought the '55 saves lives' campaign was bogus, but I still kind of like
the idea - if you must arbitrarily set the limit at 55 - of anything
between 55 and 75 being an energy offence as opposed to an insurance hiking
moving violation and crime against humanity. Sort of like the pay to
pollute gambit for industry.


Bob

I ran across an article just a few days ago debunking '55 saves
lives', I'll see if I can locate it again.

We (in Arizona) are about to raise all freeway speed limits to 75,
which is the "granny" speed around here.

I understand they've been nailing people right and left doing 110+ on
Loop 101 ;-)

...Jim Thompson

I used to drive from Phoenix to Prescott fairly regularly, and if you drove
less than 80, cars would blister your paint passing you


Bob

 

[Jim Thompson]

On Fri, 15 Apr 2005 11:27:44 -0700, Bob Stephens <roberts@dcxchol.com>
wrote:

On Fri, 15 Apr 2005 11:20:14 -0700, Jim Thompson wrote:

On Fri, 15 Apr 2005 10:37:02 -0700, Bob Stephens <roberts@dcxchol.com
wrote:

On Fri, 15 Apr 2005 17:21:13 GMT, Richard the Dreaded Libertarian wrote:

On Thu, 14 Apr 2005 22:23:32 -0700, Jim Thompson wrote:

I got an "energy ticket"... back in the Carter double-nickel days ;-)

Let's not blame Jimmy for what was actually an Imperial Edict from your
fair-haired proto-neocon, Richard M. Nixon, AKA Trickee Dickee.

Thanks,
Rich

I thought the '55 saves lives' campaign was bogus, but I still kind of like
the idea - if you must arbitrarily set the limit at 55 - of anything
between 55 and 75 being an energy offence as opposed to an insurance hiking
moving violation and crime against humanity. Sort of like the pay to
pollute gambit for industry.


Bob

I ran across an article just a few days ago debunking '55 saves
lives', I'll see if I can locate it again.

We (in Arizona) are about to raise all freeway speed limits to 75,
which is the "granny" speed around here.

I understand they've been nailing people right and left doing 110+ on
Loop 101 ;-)

...Jim Thompson

I used to drive from Phoenix to Prescott fairly regularly, and if you drove
less than 80, cars would blister your paint passing you


Bob

Yep. I'm heading up there in about two hours... transporting a
15-passenger van-load of Girl Scouts to camp ;-)

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Bob Stephens]

On Fri, 15 Apr 2005 12:03:47 -0700, Jim Thompson wrote:

On Fri, 15 Apr 2005 11:27:44 -0700, Bob Stephens <roberts@dcxchol.com
wrote:

On Fri, 15 Apr 2005 11:20:14 -0700, Jim Thompson wrote:

On Fri, 15 Apr 2005 10:37:02 -0700, Bob Stephens <roberts@dcxchol.com
wrote:

On Fri, 15 Apr 2005 17:21:13 GMT, Richard the Dreaded Libertarian wrote:

On Thu, 14 Apr 2005 22:23:32 -0700, Jim Thompson wrote:

I got an "energy ticket"... back in the Carter double-nickel days ;-)

Let's not blame Jimmy for what was actually an Imperial Edict from your
fair-haired proto-neocon, Richard M. Nixon, AKA Trickee Dickee.

Thanks,
Rich

I thought the '55 saves lives' campaign was bogus, but I still kind of like
the idea - if you must arbitrarily set the limit at 55 - of anything
between 55 and 75 being an energy offence as opposed to an insurance hiking
moving violation and crime against humanity. Sort of like the pay to
pollute gambit for industry.


Bob

I ran across an article just a few days ago debunking '55 saves
lives', I'll see if I can locate it again.

We (in Arizona) are about to raise all freeway speed limits to 75,
which is the "granny" speed around here.

I understand they've been nailing people right and left doing 110+ on
Loop 101 ;-)

...Jim Thompson

I used to drive from Phoenix to Prescott fairly regularly, and if you drove
less than 80, cars would blister your paint passing you


Bob

Yep. I'm heading up there in about two hours... transporting a
15-passenger van-load of Girl Scouts to camp ;-)

...Jim Thompson

Give my regards to Whiskey Row!

Bob

 

[DaveC]

On Fri, 15 Apr 2005 01:26:58 -0700, Pooh Bear wrote
(in article <425F7AD2.28FB67BD@hotmail.com&gt:

Best advice ( dunno if they're available over there yet ) is to get a
GPS based device that compares your location with all known speed trap
sites.

And how would you know about the "known" traps? If I've driven by them before
(personal knowledge of the trap), I wouldn't need GPS.

You got a list of them?
--
Please, no "Go Google this" replies. I wouldn't
ask a question here if I hadn't done that already.

DaveC
me@privacy.net
This is an invalid return address
Please reply in the news group