985 - Accusweep Missed a Ka Band Alert

**GTO_04** · 03-12-2006, 07:16 PM

I recently got my 985 back from BEL after being repaired. It was sent in for repair because it stopped picking up 34.7 GHz Ka band signals.

I went cruising last night in a nearby town that uses Stalker Dual radars that, as far as I know, operate on 34.7 GHz. The 985 gave sufficient warning of the first signal I picked up, and it was on a par with V1 (version 1.7). The rear antenna of the V1 did pick up the Ka band signal at a greater range than the BEL and the front antenna on the V1. But still the performance of the BEL and the V1 was as expected. I made two more runs at the Stalker radar. The cops were not in their cars at the time and the radar was transmitting continuously. The first run was with just the 985 on. There was traffic in between me and the radar and it could have been blocking the signal at times. I got .6 mile of warning, which was normal for that terrain and I was driving around a slight curve. The only thing that concerned me was the signal totally disappeared as I drove toward the radar. It was gone for several seconds, and there was not enough traffic to totally block the signal. As I got closer to the radar it came back. And the cops were still out of their cars as I drove by. I did run the 985 in Accusweep mode and Highway mode.

My second run was with the only the V1 powered up. The V1 picked up the signal at the same distance, but the signal never dropped out like it did on the 985. So this make me wonder if the 985 is totally working right.

I went on another test drive tonight, and the results are really strange. I had Accusweep and Highway modes on. This test run was in the same town where AFAIK all the cops use Stalker Duals on 34.7 GHz. The V1 picked up a Ka band signal and it got stronger and stronger, eventually to full scale. The BEL was totally silent, even at point-blank range!

After I pass the cop, and after he was out of range, the 985 picks up a short 33.7 GHz false alarm as I passed another car. The V1 was silent.

I decide to make another run, but with Superwide mode enabled instead of Accusweep. The V1 picked up a Ka band signal, and a second or two later the 985 started alerting! The tech mode display was showing a frequency of 35.2 GHz! What's up with that?

Something doesn't add up here! Based on my results, one cannot rely on Accusweep mode in the US anymore. Unless the Accusweep mode is just not working correctly on mine. Is it possible that some Stalkers are now operating on 35.5 GHz? Even if that's possible, isn't 35.2 rather far away from 35.5 GHz? Or is is possible that Stalker was set up to run at 35.2 GHz? I will double check to see if that department bought any new radar units, but I doubt that they have.

So has anyone had Accusweep fail alert to a Ka band radar in the US? Has Accusweep lost its usefulness? I noticed that BEL does not offer Accusweep on its newer models like the 995 and STi. Did they do that for a reason? Are other Ka band frequencies now being used in the US? Or is my BEL just malfunctioning?

Something is not right here.

GTO_04

**jimbonzzz** · 03-12-2006, 07:35 PM

Either the BEL is malfunctioning (LO out of tune) or V1 interfered with the BEL.

Jim

**GTO_04** · 03-12-2006, 07:54 PM

Originally Posted by jimbonzzz

Either the BEL is malfunctioning (LO out of tune) or V1 interfered with the BEL.

Jim

That makes sense. If the LO is out of tune, wouldn't the tech display frequency also be off? It depends where in the circuit the frequency measurement is made.

The V1 has never interefered with the BEL before, but anything is possible. When I turned Accusweep off it did pick up the radar, but at 35.2 GHz.

I'll probably have to send it in again.

GTO_04

**nvr2fast** · 03-12-2006, 08:19 PM

Well, I can say that the local Multanova 6F photo radars are supposed to operate on 34.36Ghz, but drift down to as low as 34.200Ghz. The V1's EURO mode (similar to Accusweep in that it only detects certain specific frequency or a few in the case of Accusweep), does NOT detect out-of-tune radars.

So, if the cop's radar really was out of tune, then you're screwed unless you run on wideband mode (same as the case with the V1).

Ask Dilip all about this, since he also got bitten by this, in fact, jsut the other night my X50 (wideband) detected a photo radar that his V1 euro mode was silent too, and hte radar was at 34.23Ghz.

WHen narrowband/accusweep/EUROmode/etc. works, it works great and wonderful, with much longer warning, but when it FAILS to work, it is terrible, no warning at all!

**Rottman** · 03-12-2006, 08:54 PM

GTO, the Tech display is known to be wrong many times.....

**GTO_04** · 03-12-2006, 09:08 PM

Originally Posted by davekr

GTO, the Tech display is known to be wrong many times.....

Yeah, that's a consideration too. Either the tech display just isn't all that accurate and/or the 985 LO is out of tune, or the Stalker is operating on a new frequency outside of Accusweep.

Looks like the BEL is going back...........again. For an $85 charge, they could at least fix it right the first time.

GTO_04

**yaks1974** · 03-12-2006, 10:18 PM

GTO_04:-I noticed that BEL does not offer Accusweep on its newer models like the 995 and STi.

The BEL STi does have Accusweep.

**compu44** · 03-12-2006, 10:22 PM

Originally Posted by yaks1974

GTO_04:-I noticed that BEL does not offer Accusweep on its newer models like the 995 and STi.

The BEL STi does have Accusweep.

Nope, the STI has Autoscan, not Accusweep. Two completely different animals.

**amoney** · 03-13-2006, 06:40 AM

All I can say GTO, is that when I used Ka wide mode and accusweep mode I came accross some freq that were out of bounds for AccuSweep to pickup, and you know I was 100% sure I saw and noted the freq correctly. I then did another road trip some time later and along the same route enou****ered NO crazy freq, so I then thought I must have screwed up and recorded the wrong number, now you bring this all back up. This subject has been talked about extensively, we know that the tech mode can be alittle off but seem to hold true the first 3 digits, the rest is foo foo. I also know that the tech mode numbers can jump around, not a totally different Ka gun, but enough to be out of bounds one second then jump back within bounds for AccuSweep to alert to. I have seen this while in Ka wide mode.

So my initial thoughts were that the RD itself knows what to alert to, but there was secondary processing to show the tech display and that goes goofy. So I did not worry and put it in AccuSweep mode and no problems, no misses here in Florida. But now you bring this all back to the surface and I wonder if maybe sometimes the RD just pulls a windoze and goes 2+2=5 and we get this junk, if your in Ka wide mode no problem, BUT if your in AccuSweep mode your screwed.

Too bad you do not have another RD tech mode to compare too. Just to see the numbers. AccuSweep performs a bit better, but I was happy with Ka wide mode, I may have to rethink things again. Does Bell tell you what they found/repaired after sending a unit in? Kind of like a car alignment where you get the previous numbers and the new alignment numbers...??? Would be nice to know.

**GTO_04** · 03-13-2006, 07:12 AM

Originally Posted by amoney

All I can say GTO, is that when I used Ka wide mode and accusweep mode I came accross some freq that were out of bounds for AccuSweep to pickup, and you know I was 100% sure I saw and noted the freq correctly. I then did another road trip some time later and along the same route enou****ered NO crazy freq, so I then thought I must have screwed up and recorded the wrong number, now you bring this all back up. This subject has been talked about extensively, we know that the tech mode can be alittle off but seem to hold true the first 3 digits, the rest is foo foo. I also know that the tech mode numbers can jump around, not a totally different Ka gun, but enough to be out of bounds one second then jump back within bounds for AccuSweep to alert to. I have seen this while in Ka wide mode.

So my initial thoughts were that the RD itself knows what to alert to, but there was secondary processing to show the tech display and that goes goofy. So I did not worry and put it in AccuSweep mode and no problems, no misses here in Florida. But now you bring this all back to the surface and I wonder if maybe sometimes the RD just pulls a windoze and goes 2+2=5 and we get this junk, if your in Ka wide mode no problem, BUT if your in AccuSweep mode your screwed.

Too bad you do not have another RD tech mode to compare too. Just to see the numbers. AccuSweep performs a bit better, but I was happy with Ka wide mode, I may have to rethink things again. Does Bell tell you what they found/repaired after sending a unit in? Kind of like a car alignment where you get the previous numbers and the new alignment numbers...??? Would be nice to know.

The repair paperwork that I got back only said "repaired antenna." If I was having trouble just on 34.7GHz, I would have thought the problem would be something other than the antenna. And if the antenna needed repair wouldn't all of the bands be affected to some extent?

I have never had Accusweep miss a warning before, and that worries me.

IIRC here is what Accusweep covers:

33.8GHz +/- 100 MHz
34.7GHz +/- 100 MHz
35.5GHz +/- 100 MHz

So, if my Tech Mode, and Accusweep is working correctly, the Stalker Dual SL radar I was picking up was at 35.2 GHz. I know this is not likely. But the Stalker Dual Specs say it can operate anywhere in Ka band from 33.4-36 GHz. The newer Stalker II handheld specs say 34.7 GHz only.

GTO_04