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  1. #1
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    Default K-Band at 24.166GHz.

    Picked up a K-Band signal at 24.166 GHz today. Wondering what models of radar use that frequency. It was mounted in a cruser and i'm almost positive it had a front and rear antenna.

    Secondly, what frequency does the MPH Enforcer K-Band handheld operate at?

  2. #2
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    Quote Originally Posted by compu44
    Picked up a K-Band signal at 24.166 GHz today. Wondering what models of radar use that frequency. It was mounted in a cruser and i'm almost positive it had a front and rear antenna.

    Secondly, what frequency does the MPH Enforcer K-Band handheld operate at?
    Technically, all K-Band stuff is the same.

    I got a BEL RX-65 today, and I've been playing around with the Tech mode. I tried it with 3 different K-Band radar units: a KR-10SP, a K-15, and a K-15 II. With all three of these, sometimes the tech mode is right on the money at 24.150. But I can power any of these off and back on, and sometimes the BEL will read 24.166. It seems to flip between 24.150 and 24.166 at random. It is difficult to say just how accurate the tech mode is, but at these frequencies I would say that is pretty good.

    Gunn oscillators are notoriously unstable, and will even drift some based on temperature etc. That is why you see in the specs 24.150 GHz 100 MHz (or 24.050 - 24.250 GHz) . Anything in this range is considered "normal" for K-band. You might not often see anything as low as 24.025 GHz, but if you did it would still be considered "normal". I suspect some radar units have "phased lock loops" with varactor tuning to keep them on freq. But, there really isn't a way to differentiate between K-band radar models based on frequency, two units of the same model could technically display different frequencies at different times.

    So, it is a good bet that the MPH enforcer is supposed to operate at 24.150 GHz 100 MHz (or 24.025 - 24.225 GHz).

    At CopRadar.com it does mention that some units operate at a 24.125 GHz center freq. I don't know what radar units these are though...

    Jim

  3. #3
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    Thanks for the info. You're just loaded with useful knowledge. If you ever need any tech advice (computer stuff) ask me and i'll tell you anything you need to know.

    Have fun with the RX- really neat toy

    Spec display works nicely with it on Ka, I do know that. It shows 33.800 every time when one of the city cops here is driving around with his Bee3 in constant-on mode (what a waste of money that was). I don't trust the spec display at all for false identification, but it is neat to play with. I've seen too many K band alerts that are on the same frequency to three decimals as door openers for it to be of much use there. I keep the standard single threat meter on 99% of the time, it's extremely accurate, and I do better ID'ing falses with it then the spec display. There's few falses that exceed 3 bars on K.

    The RX is a truly remarkable unit though. I just had a ~1.5 mile alert on instant-on K band today (the frequency I asked about) over some small hills with other traffic. That's pretty impressive as far as i'm concerned.

  4. #4
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    I did some more playing around with the Tech Mode, this time I was messing with one of my K-Band gunnplexers. I tuned it using the tuning screw to see how the tech mode would react.

    What actually gets displayed in tech mode seems to be in fixed increments. Here's the different readings I got on K-band, no matter how little I turned the screw:

    24.100
    24.116
    24.132
    24.150
    24.166
    24.182
    24.200
    24.216
    24.232

    That was the full tuning range of my gunnplexer...
    I'm sure you see the pattern: 00, 16, 32, 50, 16, 32, 00 etc. So basically, for each 100 MHz increment in K-band you'll only see 7 different values on the tech display.

    Although seeing the decimal out to three places kind of misleads you into thinking you have that kind of accuracy, I can't complain about an accuracy of 16-18 MHz. Definitely isn't bad, especially for the price. A microwave frequency counter would definitely set you back a heck of a lot more.

    I'm still having funn messing with this detector, I'll pass along anythng else I find...

    Jim

  5. #5
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    Jim, you say the TECH DISPLAY mode shows 7 (Seven) different values? You indicated 9. Could it possibly display more? depending on what it detects of course?

    Here's my thought on it: BEL set in those displayed freqs as the most likely detected within the +/- 100Mhz range. Very good info you gave though; I'm leaning toward the RX65 myself.

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    Quote Originally Posted by SETITOFF
    Jim, you say the TECH DISPLAY mode shows 7 (Seven) different values? You indicated 9. Could it possibly display more? depending on what it detects of course?
    Well, 7 values for every 100 MHz (i.e. 24.100-24.200). So for the full 200MHz K-band range (24.050 - 24.250) I would expect to see 13 different values, following the same pattern.

    I don't know if the BEL is capable of detecting beyond 24.050 - 24.250, would expect it to at least display this full range using the same pattern. But, that was as far as I could tune my gunnplexer so I couldn't test the response further. I might be able to tune it some using the volatage supply though, I might try that...

    Quote Originally Posted by SETITOFF
    Here's my thought on it: BEL set in those displayed freqs as the most likely detected within the +/- 100Mhz range. Very good info you gave though; I'm leaning toward the RX65 myself.
    Not likely, there aren't really any "most likely detected" freqs. Everything is set to either 24.150 (and possibly 24.125). The +/- 100 MHz is to allow for a margin of error and still be considered normal. Gunn oscillators can and will drift over time, and with changes in temperature etc.

    The BEL probably doesn't have the frequency resolution beyond 16-18 MHz, so it just displays whatever the closest value is.

    The tech display won't tell you too much on X and K band, but on Ka it has the potential of telling you what model of radar unit is being used based on the frequency. Some people seem to have the wrong idea that they can reliably identify false alerts by the frequency alone. If this was indeed possible, then the BEL or Escort would simply not report alerts on frequencies that aren't police radar. The bottom line is, anything the units detect have the potential of being police radar.


    Jim

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    So what is the best way to distinquish real threats from false alerts? The bottom line is it doesn't matter, when the the detector goes off, let off the gas and be alert. But beyond that its fun to learn to differentiate between the two. From the information above it appears best practice would be to leave my RX65 on Strength Meter and not get too excited if its only one or two clicks. Is that correct?

    For me the Laser alerts appear harder to distinquish because there are more potential sources of false alerts, including direct sunlight.

    I must say that having driven around for 4 days now with a detector has made driving more fun (I feel like a Top Gun pilot with a bogey on my tail when the RX65 lights up and announces "K-Band" or "Laser"), and it has made me more aware of watching my speed. I didn't buy a detector so I can go 100mph when nobody's watching. I bought it so I'd have a little grace period when I'm not paying attention (which is most of the time). I read somewhere that Colorado Springs has increased their motorcycle force from 9 to 29 over the past few years, and I don't want to be one of the "selected" citizens that get to pay their salary! (Although I did make a "contribution" a couple of months ago which is what motivated me to buy a detector. )

  8. #8
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    Quote Originally Posted by COBEL
    So what is the best way to distinquish real threats from false alerts? The bottom line is it doesn't matter, when the the detector goes off, let off the gas and be alert. But beyond that its fun to learn to differentiate between the two. From the information above it appears best practice would be to leave my RX65 on Strength Meter and not get too excited if its only one or two clicks. Is that correct?
    That's a pretty good practice I think. Just be alert until you have identified the source of the signal. For example, around where I live, there are a lot of CVS Pharmacies, and I can always count on K-band falsing near them because of their automatic doors. Grocery stores are another big culprit.

    If you drive the same routes over and over, you'll know where falses occur, so you'll also know when there's a new signal that isn't usually there. But even if you drive different routes, after a while when you get used to the detector you'll have more of an "intuition" about what is false and what isn't without even thinking about it.

    Here's a couple of things that might help indicate a false, but don't necessarily mean a false by themselves, any of these could also potentially be police radar:

    -In expert meter mode, the alerts come in pairs
    -In tech display, you might find that most K-band radar guns in your area are "right on the money", while many motion sensors have drifted off of the center freq
    -You might find that most police in your area use Ka radar, and that most K-band alerts are door openers
    -You're in the parking lot of a supermarket

    The point is, utilize whatever information is at your disposal, both from your detector and your surroundings. Have fun!


    Jim

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    You hit it right on the $$$ COBEL. IF it talks, slow down.

    jimbonzzz

    [there aren't really any "most likely detected" freqs]

    The RD manufacturers either know or should know the freqs of the radar guns out there. It seems practical to set the display to show those specific freqs when detected at those increments.

    If a gun's freq were to drift to say 24.072 we would expect that freq to be displayed, correct? But what if the display is set to show only the closest freq? That was the point I was trying to make. I'd like to see the results using a freq generator too.

  10. #10
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    Quote Originally Posted by SETITOFF
    The RD manufacturers either know or should know the freqs of the radar guns out there. It seems practical to set the display to show those specific freqs when detected at those increments.
    For K-band, all radar units have the same operational freq: 24.150 GHz (a few possibly at 24.125).

    Different manufacturers use different freqs for Ka, so it is possible that they could make the tech mode work like that for Ka. But I would expect it to work similar to the way it does for K.

    Quote Originally Posted by SETITOFF
    If a gun's freq were to drift to say 24.072 we would expect that freq to be displayed, correct? But what if the display is set to show only the closest freq? That was the point I was trying to make. I'd like to see the results using a freq generator too.
    Based on what I found, if a a gun's freq drifted to 24.072, I would expect the tech display to show either 24.066 or 24.082 (depending on how it calculates or "rounds"). It would definitely be nice to have access to a microwave freq counter though...


    Jim

 

 

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