This type of product is advertised almost everywhere that it helps you
avoid tickets etc. I imagine that it must transmit a signal on the
same freq. as the radar gun at the moment it receives the police
transmission. Even at low power can this still meet part 15 of the FCC
rules or any part for that matter? I happen to drive slowly but
millions of people don't. Can someone please tell me how it works? How
can something like this product which for all intents and purposes
"interferes with police business" be legal? Just wondering. Lenny

On 2/15/2011 10:32 AM, wrote:
How can something like this product which for all intents
and purposes "interferes with police business" be legal?

Like anything else, it's legal until they decide to prosecute.

And the police have been coming up with more and more creative
ways of prosecuting.

For example, making a video or audio recording of a police
officer is now construed as illegal wiretapping and they will
do their best to put you in prison for it.

As in all aspects of life, the best course is to consider, "Is
somebody going to find someway to throw me in prison for this?"

If the answer is even remotely a "yes", then don't do it.

Jeff

On 02/15/2011 10:49 AM, Jeffrey Angus wrote:
On 2/15/2011 10:32 AM, wrote:
How can something like this product which for all intents
and purposes "interferes with police business" be legal?

Like anything else, it's legal until they decide to prosecute.

And the police have been coming up with more and more creative
ways of prosecuting.

For example, making a video or audio recording of a police
officer is now construed as illegal wiretapping and they will
do their best to put you in prison for it.
No kidding? So if I use my digital recorder to record a police
officer giving me a ticket and he says something illegal the
recorder catches, I could go to jail for recording it? I would
think the recorder would be considered a personal security device
and I could record anything I wanted as long as I was there. I
record a lot of conversations without people knowing, and the
cops usually record traffic stops. I haven't been stopped in
over twenty years but all the cops in a nearby town a as crooked
as they can be, everyone knows they control most of the crime in
our area.


As in all aspects of life, the best course is to consider, "Is
somebody going to find someway to throw me in prison for this?"

If the answer is even remotely a "yes", then don't do it.

Jeff




--
Is Obama an Internet Junkie? Why does he think it is the US governments
mission to spend $18,000,000,000.00 billion dollars to get high speed
Internet to all Americans? Shouldn't private companies do that? A better
use of that money would be to build Waste Incinerators that cleanly burn
trash and generate electricity for every city in the US. There are
already 140 in the US, lets build more, and stop dumping trash in the
oceans.

Mysterious Traveler wrote:
On 02/15/2011 10:49 AM, Jeffrey Angus wrote:
On 2/15/2011 10:32 AM, wrote:
How can something like this product which for all intents
and purposes "interferes with police business" be legal?

Like anything else, it's legal until they decide to prosecute.

And the police have been coming up with more and more creative
ways of prosecuting.

For example, making a video or audio recording of a police
officer is now construed as illegal wiretapping and they will
do their best to put you in prison for it.
No kidding? So if I use my digital recorder to record a police
officer giving me a ticket and he says something illegal the
recorder catches, I could go to jail for recording it? I would
think the recorder would be considered a personal security device
and I could record anything I wanted as long as I was there. I
record a lot of conversations without people knowing, and the
cops usually record traffic stops. I haven't been stopped in
over twenty years but all the cops in a nearby town a as crooked
as they can be, everyone knows they control most of the crime in
our area.

In Pennsylvania it's illegal to record someone without his permission
without a court order. AFAIK even police cars with video recording
equipment don't record the audio.

Jerry

On 2/15/2011 1:15 PM, Mysterious Traveler wrote:
No kidding? So if I use my digital recorder to record a police
officer giving me a ticket and he says something illegal the
recorder catches, I could go to jail for recording it?


Think what you might about the legality of it, but the people
with the guns make the rules.

http://blogs.miaminewtimes.com/riptide/2011/01/can_police_arrest_you_for_vide.php

Jeff

" wrote in
:

This type of product is advertised almost everywhere that it helps you
avoid tickets etc. I imagine that it must transmit a signal on the
same freq. as the radar gun at the moment it receives the police
transmission. Even at low power can this still meet part 15 of the FCC
rules or any part for that matter? I happen to drive slowly but
millions of people don't. Can someone please tell me how it works? How
can something like this product which for all intents and purposes
"interferes with police business" be legal? Just wondering. Lenny


Doesn't matter. The cops use lasers, not radar, now.

waste of money

On 02/15/2011 03:55 PM, Jeffrey Angus wrote:
On 2/15/2011 1:15 PM, Mysterious Traveler wrote:
No kidding? So if I use my digital recorder to record a police
officer giving me a ticket and he says something illegal the
recorder catches, I could go to jail for recording it?


Think what you might about the legality of it, but the people
with the guns make the rules.

http://blogs.miaminewtimes.com/riptide/2011/01/can_police_arrest_you_for_vide.php


Jeff

I can see that the situation of those people videotaping the police
could be construed as disturbing the peace, but if they hadn't made
a big scene of it, and if the police weren't doing anything illegal,
the police shouldn't be afraid to be filmed. Video can help keep
cops honest. With all the cell phones that can take video, there
should be a law allowing anyone to take video of anything that happens
in front of them, including audio recording anything. Anything else
would be a violation of our civil rights, otherwise cities with CCTV
cameras, where video of citizens committing crimes are used against
them, that video should be excluded. The law should be fair for
everyone or fair for no one. I've often thought cops should have to
wear a video camera that also records audio, for their entire shift,
then downloaded and saved when the shift is over. Thats just how I
feel and I'm by no means a liberal.


--
Is Obama an Internet Junkie? Why does he think it is the US governments
mission to spend $18,000,000,000.00 billion dollars to get high speed
Internet to all Americans? Shouldn't private companies do that? A better
use of that money would be to build Waste Incinerators that cleanly burn
trash and generate electricity for every city in the US. There are
already 140 in the US, lets build more, and stop dumping trash in the
oceans.

On 2/15/2011 5:20 PM, Mysterious Traveler wrote:
Video can help keep cops honest.

And there in lies the rub.

Every time something is proposed to make them do their
job correctly and legally, they throw their hands up, "But
we can't do our job!" and the assorted unions step in to
block it as well.

The "management" gets involved and finds new creative ways
to distort laws to their own purposes to "protect their own."

Jeff

On Feb 15, 6:40*pm, Jeffrey Angus wrote:
On 2/15/2011 5:20 PM, Mysterious Traveler wrote:

Video can help keep cops honest.

And there in lies the rub.

Every time something is proposed to make them do their
job correctly and legally, they throw their hands up, "But
we can't do our job!" and the assorted unions step in to
block it as well.

The "management" gets involved and finds new creative ways
to distort laws to their own purposes to "protect their own."

Jeff

This is all very interesting but can anyone please answer my original
question? IE how they work and how it can be legal? Lenny

On 2/16/2011 9:06 AM, wrote:
This is all very interesting but can anyone please answer my original
question? IE how they work and how it can be legal? Lenny

Try this:
http://en.wikipedia.org/wiki/Radar_detector

Jeff

On Tue, 15 Feb 2011 08:32:11 -0800 (PST),
" wrote:

This type of product is advertised almost everywhere that it helps you
avoid tickets etc.

Episode 18: Beat the Radar Detector
http://mythbustersresults.com/episode18

I imagine that it must transmit a signal on the
same freq. as the radar gun at the moment it receives the police
transmission.

You have a good imagination. The illegal ones are essentially radar
jammers. That's not as easy as it sounds as getting the timing just
right so that it coincides with a radar *PULSE* is tricky. Most
handheld radars now work on several bands simultaneously, making a
universal radar jammer somewhat difficult and expensive to produce.

Even at low power can this still meet part 15 of the FCC
rules or any part for that matter?

The FCC fails to appreciate such products:
http://www.fcc.gov/eb/Orders/2007/DA-07-299A1.html
http://www.radarjammer.com/news/fcc-seizure.html
Note the $25,000 fine. Intentional Part 15 radiators (as opposed to
incidental radiators) are restricted from operating in various bands
(15.205) which include all the radar bands. Nice try.
http://www.hallikainen.com/FccRules/2010/15/205/

I happen to drive slowly but
millions of people don't.

Careful. I've received a ticket for driving too slowly on the
freeway.

Can someone please tell me how it works?

How what works? There are dozens of products, varying from crude
jammers to ultra-sophisticated military ECM rehashes. Each works
somewhat differently. This might help:
http://www.radarjammer.com

How
can something like this product which for all intents and purposes
"interferes with police business" be legal? Just wondering. Lenny

47 U.S.C. S 333 of the FCC rules clearly states that active radar
jammers are illegal. Note that S 333 is up for revision due to
intentional cell phone jamming in prisons etc.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Tue, 15 Feb 2011 08:32:11 -0800 (PST),
" wrote:

This type of product is advertised almost everywhere that it helps you
avoid tickets etc. I imagine that it must transmit a signal on the
same freq. as the radar gun at the moment it receives the police
transmission. Even at low power can this still meet part 15 of the FCC
rules or any part for that matter? I happen to drive slowly but
millions of people don't. Can someone please tell me how it works? How
can something like this product which for all intents and purposes
"interferes with police business" be legal? Just wondering. Lenny
One approach was describe several decades ago in a 'build it
yourself' project in 'Radio Electronics' magazine.

Speed radar works by sending a high frequency pulse and comparing the
frequency of the returned signal to the original. The frequency shift
of the return pulse will be proportional to the relative speed of the
radar gun and the object generating the reflection.

The R-E article was for a 'radar gun calibrator'. By taking the
received signal, amplifying it, modulating it, and transmitting only
one of the sidebands, a synthetic 'echo' would be produced with the
precise frequency offset desired.

As far as selling them, don't bother. You can make more money by
selling tinted plastic license plate covers, claiming they will 'fool
photo speed enforcement cameras'. Of course, the real fool with be
the person sending you his money.

PlainBill

Jeff Liebermann wrote in
:

On Tue, 15 Feb 2011 08:32:11 -0800 (PST),
" wrote:

This type of product is advertised almost everywhere that it helps you
avoid tickets etc.

Episode 18: Beat the Radar Detector
http://mythbustersresults.com/episode18

I imagine that it must transmit a signal on the
same freq. as the radar gun at the moment it receives the police
transmission.

You have a good imagination. The illegal ones are essentially radar
jammers. That's not as easy as it sounds as getting the timing just
right so that it coincides with a radar *PULSE* is tricky. Most
handheld radars now work on several bands simultaneously, making a
universal radar jammer somewhat difficult and expensive to produce.

How are the HANDHELD radar guns multi-band?
they would have to have multiple Gunn oscillators,too.

And more than one feed horn.(antenna)
Most that I've seen on police cars are pretty small units.

AFAIK,most radar guns are Doppler,and the receiver reads the strongest
signal it receives,so transmitting a signal from your "jammer" overpowers
the reflected radargun signal.That jammer signal has to be near in freq
to the gun's signal,or it will be rejected,because it would indicate a
higher speed than the gun will measure or considers reasonable.Then the
speed gun would light it's "interference" indicator.


do you have any information on or links to these multi-band radar speed
guns?

--
Jim Yanik
jyanik
at
localnet
dot com

wrote in
:

On Tue, 15 Feb 2011 08:32:11 -0800 (PST),
" wrote:

This type of product is advertised almost everywhere that it helps you
avoid tickets etc. I imagine that it must transmit a signal on the
same freq. as the radar gun at the moment it receives the police
transmission. Even at low power can this still meet part 15 of the FCC
rules or any part for that matter? I happen to drive slowly but
millions of people don't. Can someone please tell me how it works? How
can something like this product which for all intents and purposes
"interferes with police business" be legal? Just wondering. Lenny
One approach was describe several decades ago in a 'build it
yourself' project in 'Radio Electronics' magazine.

Speed radar works by sending a high frequency pulse and comparing the
frequency of the returned signal to the original. The frequency shift
of the return pulse will be proportional to the relative speed of the
radar gun and the object generating the reflection.

The R-E article was for a 'radar gun calibrator'. By taking the
received signal, amplifying it, modulating it, and transmitting only
one of the sidebands, a synthetic 'echo' would be produced with the
precise frequency offset desired.

As far as selling them, don't bother. You can make more money by
selling tinted plastic license plate covers, claiming they will 'fool
photo speed enforcement cameras'. Of course, the real fool with be
the person sending you his money.

PlainBill


one "calibrator" I've seen was a simple one transistor oscillator,and it
was for checking radar DETECTORS.
at a short range,it would set off X-band detectors.
IIRC,it used a MF914 transistor and stripline PCB. or maybe MF912....


--
Jim Yanik
jyanik
at
localnet
dot com

On Wed, 16 Feb 2011 07:06:14 -0800 (PST),
" wrote:

On Feb 15, 6:40*pm, Jeffrey Angus wrote:
On 2/15/2011 5:20 PM, Mysterious Traveler wrote:

Video can help keep cops honest.

And there in lies the rub.

Every time something is proposed to make them do their
job correctly and legally, they throw their hands up, "But
we can't do our job!" and the assorted unions step in to
block it as well.

The "management" gets involved and finds new creative ways
to distort laws to their own purposes to "protect their own."

Jeff

This is all very interesting but can anyone please answer my original
question? IE how they work and how it can be legal? Lenny

OK, the answer... 1. They don't typically work, and 2. they are not
legal.

In theory one could build a jammer circuit, that would work with one
specific brand/mdel of radar gun, however such a system may not work
with other brands or models, and as well any attempt would violate
federal law absolutely and many states also have prohibitions against
such devices.

PeterD wrote in
:

On Wed, 16 Feb 2011 07:06:14 -0800 (PST),
" wrote:

On Feb 15, 6:40*pm, Jeffrey Angus wrote:
On 2/15/2011 5:20 PM, Mysterious Traveler wrote:

Video can help keep cops honest.

And there in lies the rub.

Every time something is proposed to make them do their
job correctly and legally, they throw their hands up, "But
we can't do our job!" and the assorted unions step in to
block it as well.

The "management" gets involved and finds new creative ways
to distort laws to their own purposes to "protect their own."

Jeff

This is all very interesting but can anyone please answer my original
question? IE how they work and how it can be legal? Lenny

OK, the answer... 1. They don't typically work, and 2. they are not
legal.

In theory one could build a jammer circuit, that would work with one
specific brand/mdel of radar gun, however such a system may not work
with other brands or models, and as well any attempt would violate
federal law absolutely and many states also have prohibitions against
such devices.


"in theory",one could build a channelized EW(electronic warfare) suite such
as military aircraft use,and it would work with all known radarguns.
Cost would be prohibitive,though. Just fitting one to your vehicle would be
a real Project.

BTW,I wonder if a broadband whitenoise type of jammer would work,burying
the radargun's signal in the noise.
You'd need substantial power and have to cover each band used for radar
speed guns.it could be triggered by the first radar pulse and xmit long
enough for you to pass the patrol car or to slow to posted speed after
being alerted.

Still highly illegal,though.

then there was that guy who made a "stealth" car,faceted like the F-117.
no radar return,no speed measurement. :-)


--
Jim Yanik
jyanik
at
localnet
dot com

On Wed, 16 Feb 2011 15:27:25 -0600, Jim Yanik
wrote:

Jeff Liebermann wrote in
:

On Tue, 15 Feb 2011 08:32:11 -0800 (PST),
" wrote:

This type of product is advertised almost everywhere that it helps you
avoid tickets etc.

Episode 18: Beat the Radar Detector
http://mythbustersresults.com/episode18

I imagine that it must transmit a signal on the
same freq. as the radar gun at the moment it receives the police
transmission.

You have a good imagination. The illegal ones are essentially radar
jammers. That's not as easy as it sounds as getting the timing just
right so that it coincides with a radar *PULSE* is tricky. Most
handheld radars now work on several bands simultaneously, making a
universal radar jammer somewhat difficult and expensive to produce.

How are the HANDHELD radar guns multi-band?
they would have to have multiple Gunn oscillators,too.

And more than one feed horn.(antenna)

Maybe, but I've worked with horn antennas with several octave
bandwidth. It's not the horn that's bandwidth limited. It's the
waveguide feed. Figure about 0.6 octaves per standard waveguide
number:
http://www.microwaves101.com/encyclopedia/waveguidedimensions.cfm
Since only one feed need be active at a time, it's easy enough to
build a switch or just imbed the Gunn diodes or DRO (dielectric
resonant oscillator) and detector diodes in the throat of the horn,
where no waveguide is necessary. Or, just forget about the switch and
use multiple patch antennas on a PCB to feed the horn antenna:
http://www.eetimes.com/design/microwave-rf-design/4009957/Mattel-makes-a-real-radar-gun-on-the-cheap
(Note: This is an X band design, which is NOT commonly used in
current police radar guns).

Most that I've seen on police cars are pretty small units.

I'm wrong on the dual band feature. Kustom Signals advertises a "dual
K band" device (RP-1) for either K (24Ghz) or Ka (33-36Ghz) bands. I
wrongly assumed that this meant that the device was dual band. It
really means that it has two antennas, one internal and one external.
http://www.galls.com/goid/style.html?assort=general_catalog&cat=&style=LE954
http://www.kustomsignals.com/product_body2.asp?product_id=89&cat_id=8&strpagena me=fixedmount
My apologies for the wrong info and thanks for the corrections.

AFAIK,most radar guns are Doppler,and the receiver reads the strongest
signal it receives,so transmitting a signal from your "jammer" overpowers
the reflected radargun signal.That jammer signal has to be near in freq
to the gun's signal,or it will be rejected,because it would indicate a
higher speed than the gun will measure or considers reasonable.Then the
speed gun would light it's "interference" indicator.

The problem is for the jammer to figure out what frequency to jam and
then to synchronize the pulse repetition rate to that of the radar.
That's not easy when it could be arriving on X, K, Ka, and possibly Ku
bands. It doesn't take very long to get a reading and if the jammer
is listening on the wrong band or simply too slow, it will be too
late.

I have two of these radar guns, in rather poor condition:
http://www.kustomsignals.com/product_body2.asp?product_id=26&cat_id=7&strpagena me=handheld
While totally obsolete, one does function well enough to measure
speed. I must admit that I've never tested it for jamming tolerance.
Tempting to build this ummm... tester:
http://blockyourid.com/~gbpprorg/mil/wall/speed/index.html

do you have any information on or links to these multi-band radar speed
guns?

No, nor could I find any. There might be some patents but after a few
minutes of zero luck, I gave up. I recall discussing the problem
during a show with someone from Kustom Signals, who indicated that a
solution to a potential jamming problem was to frequency hop through
the available bands. At the time, only X and K bands were available,
so I assumed that this was the current technology. Apparently not.

Radar Gun FAQ:
http://www.radarguns.com/radar-guns-faq.html

Ramsey Radar Gun:
http://www.ramseyelectronics.com/cgi-bin/commerce.exe?preadd=action&key=SG7


--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com
# http://www.LearnByDestroying.com AE6KS

On Wed, 16 Feb 2011 15:31:52 -0600, Jim Yanik
wrote:

one "calibrator" I've seen was a simple one transistor oscillator,and it
was for checking radar DETECTORS.
at a short range,it would set off X-band detectors.
IIRC,it used a MF914 transistor and stripline PCB. or maybe MF912....

http://blockyourid.com/~gbpprorg/mil/wall/speed/index.html
No RF involved. It generates a tone that modulates the Gunn diode
bias voltage, thus simulating a doppler shift.

You might be thinking of the Highway Zapper Radar Activator.
http://pe2bz.philpem.me.uk/Comm/-%20Transmitters/-%20Jammers/Info-801-PoliceRadarJamming/zapper.html
http://books.google.com/books?id=KrfIjdl-EMwC&pg=PA45&lpg=PA45&dq=highway+zapper+radar+acti vator
It's an X band radar jammer that triggers radar detectors, but doesn't
seem to interfere with the police radars.

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com
# http://www.LearnByDestroying.com AE6KS

Jeff Liebermann wrote in
:



Ramsey Radar Gun:
http://www.ramseyelectronics.com/cgi...add=action&key
=SG7



I used to go to high school with John Ramsey;
he used to make little "wireless microphones".
:-)

--
Jim Yanik
jyanik
at
localnet
dot com

Jim Yanik wrote:

Jeff Liebermann wrote in
:


Ramsey Radar Gun:
http://www.ramseyelectronics.com/cgi...add=action&key
=SG7



I used to go to high school with John Ramsey;
he used to make little "wireless microphones".


Did you ever see one of his 'Service Monitors' he sold to the pager
repair business?


--
You can't fix stupid. You can't even put a band-aid on it, because it's
Teflon coated.

On Feb 18, 6:38*am, "Michael A. Terrell"
wrote:
Jim Yanik wrote:

Jeff Liebermann wrote in
:

Ramsey Radar Gun:
http://www.ramseyelectronics.com/cgi...add=action&key
=SG7

I used to go to high school with John Ramsey;
he used to make little "wireless microphones".

* *Did you ever see one of his 'Service Monitors' he sold to the pager
repair business?

--
You can't fix stupid. You can't even put a band-aid on it, because it's
Teflon coated.

It would seem to me though that if you were to simply generate even a
dead carrier on the radar frequency sufficient in strength to swamp
that of the returned signal back to the origination point wouldn't
that do the job? I don't mean to say that it would be healthy or smart
for that matter to drive around all the time while transmitting 10.0
GHZ or whatever but how complicated does this have to be? The PRC 25
and 77 had a "retransmit" function. We never really used it but I was
under the impression that it would retransmit the signal it received
perhaps to a repeater for distant communication. So if the military
had this in 1968 it must be easy to implement now. Lenny

klem kedidelhopper wrote:

On Feb 18, 6:38 am, "Michael A. Terrell"
wrote:
Jim Yanik wrote:

Jeff Liebermann wrote in
:

Ramsey Radar Gun:
http://www.ramseyelectronics.com/cgi...add=action&key
=SG7

I used to go to high school with John Ramsey;
he used to make little "wireless microphones".

Did you ever see one of his 'Service Monitors' he sold to the pager
repair business?

It would seem to me though that if you were to simply generate even a
dead carrier on the radar frequency sufficient in strength to swamp
that of the returned signal back to the origination point wouldn't
that do the job? I don't mean to say that it would be healthy or smart
for that matter to drive around all the time while transmitting 10.0
GHZ or whatever but how complicated does this have to be? The PRC 25
and 77 had a "retransmit" function. We never really used it but I was
under the impression that it would retransmit the signal it received
perhaps to a repeater for distant communication. So if the military
had this in 1968 it must be easy to implement now. Lenny


It isn't that simple. Police RADAR works by Doppler effect. I.E.,
the returned signal is mixed with with a sample of the transmitted
frequency. The difference in frequency tells your speed. Any attempt
to jam it will be a crap shoot. Even if you managed to match the RADAR
transmitter's frequency, it would still show your speed.

Military RADAR is RAdio Detection And Ranging, or a means to bounce a
signal off metallic objects, and time the reflection to measure the
distance. The rotating antenna gives you the heading. Some also change
the vertical angle to give the elevation of a target. I've serviced
both types.


--
You can't fix stupid. You can't even put a band-aid on it, because it's
Teflon coated.

On Sat, 19 Feb 2011 18:34:47 -0500, "Michael A. Terrell"
wrote:



It isn't that simple. Police RADAR works by Doppler effect. I.E.,
the returned signal is mixed with with a sample of the transmitted
frequency. The difference in frequency tells your speed. Any attempt
to jam it will be a crap shoot. Even if you managed to match the RADAR
transmitter's frequency, it would still show your speed.


You know the frequency of the signal you receive. You know your speed.
Assuming you could build a circuit to compute the necessary bits, you
should have little trouble computing the original transmitted
frequency with those two bits of information. The simply transmitting
the same frequency back should result in the desired result of a lower
reading.

PeterD wrote in
:

On Sat, 19 Feb 2011 18:34:47 -0500, "Michael A. Terrell"
wrote:



It isn't that simple. Police RADAR works by Doppler effect. I.E.,
the returned signal is mixed with with a sample of the transmitted
frequency. The difference in frequency tells your speed. Any attempt
to jam it will be a crap shoot. Even if you managed to match the RADAR
transmitter's frequency, it would still show your speed.


You know the frequency of the signal you receive. You know your speed.
Assuming you could build a circuit to compute the necessary bits, you
should have little trouble computing the original transmitted
frequency with those two bits of information. The simply transmitting
the same frequency back should result in the desired result of a lower
reading.



the active jammers I've seen program a set freq. shift to give a lesser
speed reading at the radargun. they had a switch to change it for different
speed zones.The jammer's stronger direct signal overwhelms the weaker
reflection of the gun's signal.

But white noise is broadband,so a radargun would not be able to make any
comparison to the transmitted freq. with a "white noise jammer" It would
raise the noise floor ABOVE the reflected signal,smothering it.
I believe I've seen references to radarguns having an indicator for
"jamming",and their audio output would also be an indicator,operators being
trained to recognize interference.

--
Jim Yanik
jyanik
at
localnet
dot com

PeterD wrote:

On Sat, 19 Feb 2011 18:34:47 -0500, "Michael A. Terrell"
wrote:


It isn't that simple. Police RADAR works by Doppler effect. I.E.,
the returned signal is mixed with with a sample of the transmitted
frequency. The difference in frequency tells your speed. Any attempt
to jam it will be a crap shoot. Even if you managed to match the RADAR
transmitter's frequency, it would still show your speed.


You know the frequency of the signal you receive. You know your speed.
Assuming you could build a circuit to compute the necessary bits, you
should have little trouble computing the original transmitted
frequency with those two bits of information. The simply transmitting
the same frequency back should result in the desired result of a lower
reading.


Do you know the angle the RADAR transmitter is coming from? Also, if
the display is obviously wrong, the cop will know you are using ECM to
avoid a ticket.


--
You can't fix stupid. You can't even put a band-aid on it, because it's
Teflon coated.