POP Mode (+'s and -'s)

[GET 1T DONE]

Ok, first let me get the facts straight:

If you turn on the Pro58 you will notice the P is missing at the end of the self test indicating POP OFF.

This will not help to avoid falsing from the Cobra. As I mentioned earlier in my email, I lowered the sensitivity about 10db to brief CW signals when in POP mode such as those created by the Cobra. Actually I lowered it 6db for K band and 10db for Ka.

Taking your unit out of POP mode will actually increase your K and Ka sensitivity about 1-2db.

Its ability to respond to POP radar will go from 100% to about 40% when in POP OFF mode.

Mike

POP is a bit different, because in the Whistlers it is verified that having POP off gives you 2-3db extra sensitivity on K and Ka. So, you have to weigh the risk of having POP OFF and missing a POP alert with the risk of losing the 2-3db of K and Ka sensitivity of having POP ON.

1) How does POP OFF mode translate into 1-2dB of increased sensitivity for sustained CW radar signals?

2) Given a perfectly straight, slightly concave roadway on a low humidity day, what kind of general distance increase would a 1-2dB increase in sensitivity result in?

3) Would a 3dB increase in sensitivity mean that the RD can now detect signals only half the power of the previous lowest detectable signal level? Or does 3dB of "sensitivity" not translate to 3dB (or double) "power"?

4) Is it that if the lowest detectable (alerted) signal power is, say (randomly selected) 0.5mW, that a 3dB increase in sensitivity would mean 0.25mW signals will now be alerted to... but because 0.25mW is so close to 0.5mW, and considering how fast the signal attenuates in free space, that the typical increase in initial alert distance is pretty small in real-world conditions?

Thanks for sharing your expertise. I'm just trying to quantify what this increase in sensitivity really means to the driver, and whether it's worth the trade off of reduced Cobra falses (due to the 6-10dB decrease in sensitivity to brief CW signals) in POP ON mode.

[jdong]

1) How does POP OFF mode translate into 1-2dB of increased sensitivity for sustained CW radar signals?

It's simply Whistler's algorithm. I'm guessing to reduce falses in POP ON mode, the detector reduces 1-2dB of sensitivity. Turning POP OFF will return the detector to "full" sensitivity.

2) Given a perfectly straight, slightly concave roadway on a low humidity day, what kind of general distance increase would a 1-2dB increase in sensitivity result in?

In my experience it gives like 5% increased detection distance on K band and 10% on Ka band. (X band remains more or less unchanged to my perception). It's definitely a noticeable improvement, but still not gonna make or break a save.

3) Would a 3dB increase in sensitivity mean that the RD can now detect signals only half the power of the previous lowest detectable signal level? Or does 3dB of "sensitivity" not translate to 3dB (or double) "power"?

Hmm I'm not sure the physics of how a 3dB increase in sensitivity translates to theoretical physical distance improvement, but I can tell you it's certainly not double or even a quarter of the distance.

4) Is it that if the lowest detectable (alerted) signal power is, say (randomly selected) 0.5mW, that a 3dB increase in sensitivity would mean 0.25mW signals will now be alerted to... but because 0.25mW is so close to 0.5mW, and considering how fast the signal attenuates in free space, that the typical increase in initial alert distance is pretty small in real-world conditions?

I've driven on my 1793SE (same platform as Pro 58 and 73) for hundreds of miles in POP ON and POP OFF, and I can say I don't really notice much difference between the two. Sure, if you use a stopwatch and odometer you can measure a slightly increased range in POP OFF mode but IMO it's not significant.

Put it in whichever mode you want. Personally, I keep POP ON because I don't really notice any increase in falsing in this mode, and just want to stay on the safe side with detecting POP as a prelude to an instant-on ambush, living in a state where the police have POP-capable radar.

[Jag42]

Running POP off on my Pro 78 i have noticed a increase especially in Ka band. I have only seen POP once and that was in New Mexico it went off
on a radio tower or microwave tower.

[jdong]

Running POP off on my Pro 78 i have noticed a increase especially in Ka band. I have only seen POP once and that was in New Mexico it went off
on a radio tower or microwave tower.

Do you have Beta RevB firmware? if not, then there is no sensitivity difference between POP ON and OFF on the pro-78


Also, the Whistlers do not have a separate alert for POP. They show up as regular alerts at any signal level.

There is a special PULSE alert for a signal suddenly received at full strength, but it has nothing to do with POP mode at all.

[GET 1T DONE]

1) It's simply Whistler's algorithm. I'm guessing to reduce falses in POP ON mode, the detector reduces 1-2dB of sensitivity. Turning POP OFF will return the detector to "full" sensitivity.

2) In my experience it gives like 5% increased detection distance on K band and 10% on Ka band. (X band remains more or less unchanged to my perception). It's definitely a noticeable improvement, but still not gonna make or break a save.

3) Hmm I'm not sure the physics of how a 3dB increase in sensitivity translates to theoretical physical distance improvement, but I can tell you it's certainly not double or even a quarter of the distance.

4) I've driven on my 1793SE (same platform as Pro 58 and 73) for hundreds of miles in POP ON and POP OFF, and I can say I don't really notice much difference between the two. Sure, if you use a stopwatch and odometer you can measure a slightly increased range in POP OFF mode but IMO it's not significant.

Put it in whichever mode you want. Personally, I keep POP ON because I don't really notice any increase in falsing in this mode, and just want to stay on the safe side with detecting POP as a prelude to an instant-on ambush, living in a state where the police have POP-capable radar.

Thanks for your response.

Right, didn't stop to think. The "sensitivity" is just the threshold set at which the RD will first alert. So raise the threshold... and essentially you decrease the sensitivity.

Yeah, the difference between POP ON and POP OFF is pretty much negligible in my opinion. I have some local fixed K-band speed signs by work, to which POP ON mode causes slightly poorer performance... though on the other hand, Cobra falses definitely have been decreased with POP ON (POP OFF mode guarantees you'll catch EVERY Cobra on the road!)

Perhaps I'll test the two modes against one of the K-band speed signs and report the results...