Pro-78 Finds the Cops Off-Axis, Off-Duty!

Stealthcb · 08-28-2007, 08:34 PM

So I was cruising to pick up my daughter from work tonight. Driving down North Carefree, just a smidge over the PSL. I don't push it here because the CSPD's Stetson Hills Substation is in the area, AND because I get a very consistent K-band false off a liquor warehouse (one of my favorite places!). It appears right near my first alert marker on the attached diagram.

ANYWAY, normally, I get to the liquor store and the K-band goes away. This time, it went away for a second, then popped up as Ka-band at 5-bars. Whoa! Speed check -- all's fine. So I cruise control it and keep going. The signal ramps all the way up to 9, JUST as I turn on Bloomington, which goes up a steep hill to the shopping complex where my daughter works. Then it disappears immediately.

Hmmmmmmm.

So I pick up my daughter, get back to that same intersection (pointing south this time) and I get Ka-band at 2-3 bars. This hooked me. I assumed the LEO was across Carefree somewhere to my south, so I hooked right, then left, and cruised south. Came up from that direction on the same road. Got to right before the JC Penney (my daughter's second job) and got a Ka again. It ramped up until finally, at the same intersection, it was at 9 bars again. I was searching frantically, trying to find the LEO. If there's one thing I know, it's that Ka on the 78 means LEO. Plain and simple.

Sure enough, I found the cruiser. It was parked at a Chick Fil-A in the NW corner of the intersection. It sits up about 30 feet on a hill, and the cruiser was parked at an angle, pointing roughly southeast (the blue arrow). It was, of course, unoccupied.

I wanted SOOOOO bad to go into the Chik Fil-A and say, "Hey, officer -- you left your radar on. Might want to turn it off before your battery is dead." But I didn't figure that would go over very well.

This taught me several things about my Pro-78.

1. Once again, if it says Ka -- SLOW DOWN. Especially if it's more than one beep.

2. These alleged off-axis problems from the directional horn antenna are bunk. My first alert on the westbound leg came at about a 90-degree off-axis angle. The second hit was at 90-degrees the other direction, OVER the newly built JC Penney and another store. Off-axis on the Pro-78 is fine.

3. The ranges were very good considering the 90-degree angles involved and the narrow beam used by Ka. I basically got an alert the instant I drove into the beam, whether due to angles or terrain masking. With buildings blocking the signal and traffic heavy, that was some seriously nice performance.

4. CSPD continues their transition to Ka guns. In the past, they've been a very k-heavy unit. And they continue to like constant-on, thankfully, except for the motorcycle LEOs with their stupid POP.

Oh, and I suspect the northbound alert might actually have been reflection. That small building the blue arrow points to is a church made mostly of corrugated metal siding and roofing. So I'm sure it's a wonderful radar reflector.

**pronacyk** · 08-28-2007, 08:47 PM

From 90deg off axis, you must have caught some major reflection from traffic. Ka is very directional and so is the 78 horn. For me, my 78 does not report off-axis K-band signals well. I have proven this again and again, comparing it with the pro73, v995, and the V1. From the 78, I get nothing while all the others give a semi-weak reading. I hardly think this is a bad thing, however. The less it alerts to non-police radar (the less chattier), the more seriously the user will take each alert. I'm starting to be desensitized with the amount of alerts I get with the V1.

Stealthcb · 08-28-2007, 08:50 PM

Originally Posted by pronacyk

From 90deg off axis, you must have caught some major reflection from traffic. Ka is very directional and so is the 78 horn. For me, my 78 does not report off-axis K-band signals well. I have proven this again and again, comparing it with the pro73, v995, and the V1. From the 78, I get nothing while all the others give a semi-weak reading. I hardly think this is a bad thing, however. The less it alerts to non-police radar (the less chattier), the more seriously the user will take each alert. I'm starting to be desensitized with the amount of alerts I get with the V1.

For the northbound alert, you're probably right. I added that as you typed, I think. For the other one, I think it was probably direct, as the LEO would have been shooting over the traffic around me. The angle on the car is approximate, so it's probably somewhere in the vicinity of 90, but could be less.

But I will say this -- my 78 alerts to k-band door openers MUCH farther out than the 73 did. And at weird angles, too. I can't explain it for the life of me, but door openers my 73 would ignore set the 78 off at .2-.3 miles. It's odd. If I had a digital camcorder, I'd take video to see if Michael B could explain it.

**pronacyk** · 08-28-2007, 09:02 PM

Yeah that is pretty strange. The 78 picks up maybe 10% of the usual off-axis K-band doors that the 73 had always picked up. I don't think it's my particular unit because I've gotten 1.5mi from CO K-band over many many hills which just had my jaw on the floor for a good 5 minutes.

Stealthcb · 08-28-2007, 09:12 PM

Originally Posted by pronacyk

Yeah that is pretty strange. The 78 picks up maybe 10% of the usual off-axis K-band doors that the 73 had always picked up. I don't think it's my particular unit because I've gotten 1.5mi from CO K-band over many many hills which just had my jaw on the floor for a good 5 minutes.

One of these mornings I'll experiment with it, but I think it has to do with how the 78 processes multiple signals in the same band, sometimes seeing them as one strong signal rather than many small ones. That's why multiple door openers will trigger a PULSE alert sometimes. Talk about scaring the poo out of you -- a PULSE alert in the parking lot!

**jdong** · 08-28-2007, 09:14 PM

Originally Posted by pronacyk

Yeah that is pretty strange. The 78 picks up maybe 10% of the usual off-axis K-band doors that the 73 had always picked up. I don't think it's my particular unit because I've gotten 1.5mi from CO K-band over many many hills which just had my jaw on the floor for a good 5 minutes.

I had an experience today that confirmed stealth's observations regarding the XTR-690 platform and off-axis K-band.

At the same time, the XTR-690 also for me picks up far fewer off axis door opener hits.

Hmm... better legit police radar detection, worse door opener detection. What would be the reason behind this?