Ka just tougher to detect unless pointed directly at it?

**JeepinJeff** · 05-29-2007, 10:48 AM

was coming back from lunch earlier and saw a LEO with someone pulled over on the same side of the road that I was going.
V1 was dead quiet until I passed him and just the second I did, I got a full Ka alert on the rear horn.
I guess I expected some kind of signal coming from the front as I approached him.

**kpatz** · 05-29-2007, 11:21 AM

Ka is more directional than K, so it is harder to pick up if it's not aimed straight at you. What was the terrain like? If there was nothing to reflect the signal back toward your car, it's possible that you would have gotten no, or little alert before passing the LEO.

Was the LEO in the cruiser at the time you passed him? Maybe he instant-on-ed you when you passed him.

**JeepinJeff** · 05-29-2007, 11:26 AM

he had the vehicle he pulled over, a mini van, directly in front of him. He was in the vehicle but I don't think he did an instant on as he was somewhat back to the right of the van. Farther off the road as they do to protect themselves. Terrain was a nice, flat, straight road. I had a clear line of sight of him for at least 1/4 mile probably.

**tsugsr** · 05-29-2007, 05:52 PM

Just the other night i got a 1.5 mile hit while the LEO was sitting facing the same Way i was....It was just blip of Ka, then nothing, then a blip, then nothing, but as i got about .5 a mile away, i got two to three strength, and then about 200 yards from him I got full strength till well after I passed him. That was on a pretty straight shot flat road, maybe that has something to do with it?

**JeepinJeff** · 05-29-2007, 05:59 PM

I guess when thinking about it, anything could have happened. He could have been back in the car getting ready to pull away and then flipped it back on again to go after the next poor person.

**MEM-TEK** · 05-29-2007, 06:55 PM

*****

**jimbonzzz** · 05-29-2007, 08:43 PM

Originally Posted by MEM-TEK

I suspect that the LEO had the power dialed way down on his Ka gun. This would explain why you V1's rear antenna detected it as soon as you passed the parked LEO. I bet the strong signal faded away very quickly.

Sorry, but it is not possible for the operator to adjust or "dial down" the transmit output power on any police radar unit used in the USA. I'll say it again: transmit power is at a fixed level, and cannot be changed or adjusted in any way by the operator. Some radar units have a "range" control, however this only controls receive sensitivity, much like the squelch control of a scanner or CB radio.

**MEM-TEK** · 05-29-2007, 08:55 PM

*****

**GTO_04** · 05-29-2007, 09:42 PM

Originally Posted by MEM-TEK

Originally Posted by jimbonzzz

Sorry, but it is not possible for the operator to adjust or "dial down" the transmit output power on any police radar unit used in the USA. I'll say it again: transmit power is at a fixed level, and cannot be changed or adjusted in any way by the operator. Some radar units have a "range" control, however this only controls receive sensitivity, much like the squelch control of a scanner or CB radio.

I guess you are 100% sure about this, even though (at least in the late 1980s) I had more than a few encounters with police radars where the LEO's cruiser was parked either over a hill or around a curve on the interstate. In several of these cases I was hit with instant on at fairly close range just after cresting the hill or rounding the curve, yet the received line-of-sight signal was relatively weak even though I was fairly close to the parked cruiser. I would think that it would be common sense for the radar gun manufacturers to vary the output power rather than employ a squelch knob as a method for more limited detection range. :?

Best Regards,

--Michael

I have verified this with controlled testing, and radar sales reps have told me the same thing..............the range control is a receive sensitivity control only, much like a squelch control, it is definitely not a power output control.

GTO_04

**bart99gt** · 05-30-2007, 07:26 AM

Originally Posted by MEM-TEK

Originally Posted by jimbonzzz

Sorry, but it is not possible for the operator to adjust or "dial down" the transmit output power on any police radar unit used in the USA. I'll say it again: transmit power is at a fixed level, and cannot be changed or adjusted in any way by the operator. Some radar units have a "range" control, however this only controls receive sensitivity, much like the squelch control of a scanner or CB radio.

I guess you are 100% sure about this, even though (at least in the late 1980s) I had more than a few encounters with police radars where the LEO's cruiser was parked either over a hill or around a curve on the interstate. In several of these cases I was hit with instant on at fairly close range just after cresting the hill or rounding the curve, yet the received line-of-sight signal was relatively weak even though I was fairly close to the parked cruiser. I would think that it would be common sense for the radar gun manufacturers to vary the output power rather than employ a squelch knob as a method for more limited detection range. :?

Best Regards,

--Michael

Keep in mind you're talking about a 80s technology detector.

The Gunn diodes employed in most traffic radar units are really only stable at a particular voltage, so varying their output power really isn't an option. However, they do make these diodes with different power outputs, usually ranging from 10-150 mW. Generally, the DSP guns use the lower powered transmitters, since their sensitivity is much higher than older analog units, but it also decreases detection range by radar detectors. Old K band guns usually would have been anywhere from 50-100 mW output power. X band units, including the K55, were 100-150 mW.