View Full Version : Ka falses?
brick
02-13-2005, 08:14 PM
If I've learned one thing about my V1 it's that Ka = cop. No questions, no variation. (If only that were the case with K-band alerts!) But I just got my girlfriend a Cobra XRS 9700 and I'm not so sure that the pattern stands with this detector. On one of my around-town test drives with it I picked up two or three 1/4-2/4 signal strength hits that I couldn't explain. One was near a highway overpass, so it could have easily been radar passing overhead. But the other two are a complete mystery. (They generally went away after a few seconds.) I wandered around a bit looking for someone running instant on but I couldn't find anything.
Have any of you seen similar behavior when using lower-end detectors? It seems to have OK range and filtering in other circumstances. It's just odd to me that it would false noticeably on Ka.
compu44
02-13-2005, 08:19 PM
Cobras do have some problems with Ka flases. Sometimes from other detectors, sometimes seems to be from nothing at all. Also, the Cobra units tend to occasionally identify K as Ka.
sethy
02-13-2005, 08:44 PM
Ive had a 9600 ( same thing as the 9700 only no voice) and the KA falses come from other detectors. I wasnt ever really satisfied with my 9600 because if you were hit with an instant on, it would creep up the scale and then go down, such as 1 , 2 , 3 , 4 , 5 where the other redectors would jump up to full alert
joop1987
02-13-2005, 09:02 PM
We are never going to get rid of the K band falses, but prob. more. All new automatic door openers operate on K band (24.125 GHz). As time passes, and there's less older automatic door openers, I think X band will false less. I noticed that the automatic door openers that operate on K band have 1/8 mile range or lower.
brick
02-14-2005, 05:28 AM
Also, the Cobra units tend to occasionally identify K as Ka.
Now that's a little strange. It's actually very possible that this is what happened because the two "unexplainable" falses were near a CVS (first one) and a grocery store (just a little farther down the road) with K-band door openers. I don't recall if it ever falsed on K there or if I only got the Ka warnings.
I guess the real test is whether or not it works for her. She does a lot of driving and so should have a feel for it before too long.
Hessen
02-14-2005, 06:11 AM
I have a PNI Traveller. Same deal. It will sometimes suddenly alert a breif Ka for no apparent reason......sometimes it reports K band as Ka breifly and then changes alert to K. Police up here use K band and there may the odd old X band unit still out there. It also reports breif Ka alerts in industrial areas...I suspect building alarm systems etc are setting it off.
The bottom line is it does "false" on Ka way to much.
I would never use this detector in the USA where Ka is very common, the falses would drive me nuts.
SETITOFF
02-14-2005, 03:23 PM
I have noticed a KA alert on a stretch of road here that has turned out to be an antenna source mounted high, almost like on a high voltage power line, but it is in fact an RF transmitting antenna and it is picking up Ka (it being my Cobra 9400). I would venture to bet that every RD out there will alert on this source because it is putting out a very strong signal.
I could not stop driving on this road to verify the source so I just held the RD in my hand and began scanning toward the sky and sure enough the signal got stronger as I closed in and weaker as I passed.
If you're unsure of the source and have the time to stop, try it. Scan the area, holding the RD and see if you can pinpoint the source.
compu44
02-14-2005, 10:03 PM
I have a PNI Traveller. Same deal. It will sometimes suddenly alert a breif Ka for no apparent reason......sometimes it reports K band as Ka breifly and then changes alert to K. Police up here use K band and there may the odd old X band unit still out there. It also reports breif Ka alerts in industrial areas...I suspect building alarm systems etc are setting it off.
The bottom line is it does "false" on Ka way to much.
I would never use this detector in the USA where Ka is very common, the falses would drive me nuts.
Not surprising, I believe that Cobra and PNI are both made by autowave.
Radar Roy
02-14-2005, 10:08 PM
No, Cobra and Radio Shack are made by BGTech in China
PNI is made by Autowave in Korea..
Jon_Doh
02-16-2005, 08:17 AM
The Cobra is so leaky that it causes itself to false :lol:
SETITOFF
02-16-2005, 08:36 AM
The Cobra is so leaky that it causes itself to false :lol:
Jon_Doh, just a quick question, and not to rile you up, but what factual basis do you make this statement?
How would anyone know or be able to tell how much RF leakage is put out from a RD?
brick
02-16-2005, 08:42 AM
I can tell you that the 9700 makes my V1 false on K and Ka during its startup sequence, but gets quieter thereafter. It's not the Valentine because I can then turn it off and on and it stays quiet. (I think I had X turned off on the V1, though.) Likewise, the V1 makes the Cobra false on X all the time. (Turned it off when I was testing it.) The Cobra is probably a bit more leaky just because it doesn't have the magnesium case, but it really doesn't seem to be that bad.
happya$$
02-16-2005, 04:24 PM
99% of the time when my V1 alerts me on this band it is a cop. Yeah I am like you, I wish that this was the case with K band.
pemarsh
02-16-2005, 05:24 PM
I do know if you have Ku enabled (if it comes with that option), you will have an increased number of false Ka
happya$$
02-16-2005, 05:41 PM
I have KU enabled but have not really seen an increase in Ka falsing
marlinspike
02-16-2005, 05:44 PM
I have Ku enabled too and get no Ka falsing. What I have had is some Ku falsing...only twice and only on one on ramp and one off ramp, both at different exits, and I couldn't repeat the falses.
Richard