I know that the speedometer on the Charger, and on the Honda that I currently drive are (were) NOT accurate, due to purposely using "wrong" size tires.
The Charger (really a two door Dodge Omni) had a "Ronald Regan" speedometer that only went up to 85 MPH. It was raced regularly in sanctioned SCCA autocross events, and at the local dragstrip where I often went hunting Mustang GT's. I tested the car's speedometer with the only standard that matters, a currently calibrated police radar gun!
The Charger came up with 21.4 MPH per 1000 RPM in 5th gear, tested at several speeds. 154 was obtained by bouncing off of the 7200 RPM rev limiter while passing a mid 80's Corvette. Mr Gold Chains inside the Vette was not amused that his shiny new Vette was just passed by an old Dodge Omni with peeling paint. Note, I built a wicked little 4 cylinder with a big turbo and lots of boost.
My current Honda Element has tires that are wider, but have shorter sidewalls than the recommended size. This was to gain a bit of "gear" and traction to pull a trailer through the mountain roads. The speedometer reads 7% faster than actual speed. This was tested by police lidar at 70 MPH. I have a friend who is a cop.
The last ticket I got entering main stream traffic from the collectors. All I did was maneuver into traffic in a merge situation by suddenly booting it into an opening ahead only to arrive directly behind an unmarked minivan cruiser. There's lots of circumstances where speed is needed for a few moments. I just happened to be in the wrong place at the wrong time in that instance. However I will fight this ticket in court as I don't believe this cop is certain it was me he was clocking and I did not admit to speeding. When I took him to task on it he wasn't a pillar of confidence. I also found it a little suspicious of him asking me how my driving record is before asking for my paper work.
These are the kinds of devices I want to build...... just for educational purposes, of course.
THx-RNMarsh
geared very tall🙂
during those years 1982, I was at the other end of the spectrum extremely fast off the line but limited to 3 gears and 3.73 posi. a Calif. special GM Monza with a factory 5.7 liter ( limited build ~800 cars) , , 4bbl carb and dual glass pack exhaust. I put in many suspension and brake mods. I could spin both tires on any surface😀 Gas was cheap when you could get it, luckily my good neighbor drove a gas delivery truck, he siphoned off ~ 5 Gal each morning. he said it was from the un-accounted fuel from temperature condensation.
detecting LO leakage from a radar detector? is this a problem for law enforcement I would say 99% LE agencies couldn't and wouldn't attempt an conviction, even if they had help from the experts.
The cheaper detectors (at least) radiated like crazy back in the 90's. My son and I made a 'brake light tester' with one to bother a fellow employee who drove like a nut. Not a lot to it, just retune by turning a screw thread to the operating frequency of real radar and point the horn at him. Very unlegal in case the one or two FCC inspectors happens to be nearby with a spectrum analyzer
Interesting. Why didn't you use a Gunn diode and a varactor one ? You could have gotten a lot more power (0.5W or even more).
given the right tools and best of circumstances (only car on the road etc), a LEO will have perhaps 80% certainty that he detected something , but you being a citizen wise to your rights would never admit to it and / or a car search to prove him right. but I reckon cops in parts of those 2 states will do what ever they need to do to catch the 'bad guys'.
Last edited:
3.56 final drive (FWD) with an 0.82 (I think) overdrive 5th gear. It took several different tire size swaps before I arrived at a 215/55 X 14 tire that was an optional size on a WV Sirocco 16V. This allowed me to reach 7200 RPM in 5th just as I began to run out of torque. Much taller tire and the car would slow down when shifted into 5th because I hadn't gotten far enough up the torque curve, and a shorter tire would cause me to hit the rev limiter too early in 5th, the car was still accelerating.
One of the friends I autocrossed with had a factory V8 Monza, only we called them 350's then. I believe that he had made several engine mods. It was a rather quick car, but a bit to heavy to handle on the shorter autocross courses. My FWD Charger at 2300 pounds was still outclassed by the far less powerful Miata, which were being blown off the course by the newly re-released Cooper Mini.
We made this thing in a lab inside the Motorola plant. It wasn't intended to be a radar cloaking device at first. We actually started with an 800 MHz two way radio, since that's what we all worked on for a living, and we had dozens laying around. I simply wired the TX/RX switching so both were on, and fed noise from the FM discriminator output into the TX VCO's control voltage input along with a DC voltage from a pot to set the center frequency. I also set the TX ALC circuit for 0.5 watts on a 2 watt radio and applied the same discriminator noise to the ALC loop. This gave me about 10 db of AM noise and 20 MHz of FM noise. The radio could light up the entire screen of a spectrum analyzer with snow. It could also shut the in house 800 MHz trunking system down, which was the intended effect.
We got the idea of applying a passive diode multiplier on its output after we found plans for the 1N914 multiplier in a ham radio handbook. A varactor multiplier would have been ore efficient, but we had 1N914's ( or maybe 1N4148's) and we didn't have any varactors, so we used the switching diodes.
There are two commercial radar detector detectors sold to law enforcement. The manufacturer publishes a SOP for proving the presence of radar detector, that holds up in court. I hear that the SOP in the state of Virginia is for the cop to offer the offender a choice, arrest, or the offender gets to place his detector on the road and drive his own car over it. No court needed!
Here in TN, every RADAR system I've seen in the last four years has been Hand Held LASER RADAR (LIDAR LTI 20/20?).
Detectors are useless when it is used (too late to detect).
When in college in the late 70s one student did a radar jammer as a senior project. He was able to get the Highway Patrol to test the unit. I believe it used a gunn diode and varactor . The most difficult part of the project was the waveguide/antenna system.
Detectors are useless when it is used (too late to detect).
When in college in the late 70s one student did a radar jammer as a senior project. He was able to get the Highway Patrol to test the unit. I believe it used a gunn diode and varactor . The most difficult part of the project was the waveguide/antenna system.
I really like the 80's turbo K cars i always wanted a omni gls but they are hard to find. With poor flowing cylinder heads you can crank up the boost and make a quick fun car and the bottom end seem to hold up well.
Just to clarify, I wasn't talking about a varactor multiplier, but a simpler configuration where a Gunn diode and a varactor are placed in the same resonant cavity.
The Gunn diode generates the microwaves and the varactor is used to alter the resonant frequency of the cavity.
This configuration is usually called "Gunnplexer".
In order to use it as a radar jammer, one has to feed the varactor with noise which will translate into phase noise in a certain frequency band.
This configuration is simple and can generate a few hundred miliwatts from a single Gunn diode.
Indeed, but you can buy the whole cavity + diodes on Ebay.
Two examples:
$40 assembly: 26 GHz Gunn Diode Oscillator, Varactor Tuned Experimenters Item WR-42 WG
$65 assembly: 22-24 GHz Gunn Diode Oscillator, Varactor Tuned Experimenters Item WR-42 WG
By the way, I am not advocating building radar jammers, but experimenting with microwaves can be educational.
Gunn Diode oscillator and radar application is not so hard to known. I read about it here Gunn Diode Tips - Definition, Oscillator application and more it's nice for beginners
- Status
- Not open for further replies.