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  1. #1
    Old Timer
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    Default Spectre Proofing

    I was curious to know what a RDD detects on a RD. What band leaks? If I turn off that band, could that make it Spectre proof?

  2. #2
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    Default Re: Spectre Proofing

    Quote Originally Posted by Sethy
    I was curious to know what a RDD detects on a RD. What band leaks? If I turn off that band, could that make it Spectre proof?
    This brings up a point that I have always wondered about.
    I could be wrong but I think that when a detector picks up an RDD it is like a real radar gun encounter, so one could simply turn off their own detector if running into this illegal situation.
    Anybody know?

  3. #3
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    Default

    The RD produces its own radio waves internally. That's what the Local Oscillator ("LO") does. The RD uses these radio waves to mix down the incoming signals so that they are easier to process. Those radio waves, in the range of 11-15GHZ, are what leak out for the Spectre to find. The only way to make it truly spectre proof would be to totally contain these LO emissions. I couldn't tell you how that would be done.

  4. #4
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    Default Re: Spectre Proofing

    Quote Originally Posted by V1 Dave
    Quote Originally Posted by Sethy
    I was curious to know what a RDD detects on a RD. What band leaks? If I turn off that band, could that make it Spectre proof?
    This brings up a point that I have always wondered about.
    I could be wrong but I think that when a detector picks up an RDD it is like a real radar gun encounter, so one could simply turn off their own detector if running into this illegal situation.
    Anybody know?
    I think that this is difficult because the Spectre II and III are VERY well sealed up. (The way our detectors ought to be!) This makes them difficult to impossible to detect before they've already picked you up.

  5. #5
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    Default

    It is the mostly the local oscillators that leak, but some mixer products leak too. Traditionally, the "local oscillators" (or LO's) in detectors operated in the 11-12 Ghz range, but many newer detectors have LO's in the 13-15 Ghz range (Valentine Escort BEL etc).

    Turning off bands won't make anything Spectre proof. No matter what bands you turn off, the LO will still be operating.

    Jim

  6. #6
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    The only permenant solution to the Spectre would be to "seal" the detector up so that no emissions are leaked at all. One aspect would be to "seal" the case so that no RF leaks out, but a lot of the leakage comes from the antennas. So, the idea would be to put a bandpass filter between the antenna and first mixer. The problem is, most filters that would prevent the emissions completely would be too "lossy", and would result in a big performance hit as they would also attenuate any incoming signals.

    Jim

  7. #7
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    Default

    As it stands right now, the only thing that will shut that LO up is to turn off the RD. From what I do know (not much...lol) there is no specific freq/band that RDDs are sniffing. There may be a range of freqs/bands but not any specific. I'm still trying to find out if they work on a 'passive search' detection capability as some radars I used to work on.

  8. #8
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    On this page it says 11-11.4 Ghz, and 13-15 GHz:
    http://www.radarbusters.com/support/...-detectors.asp

    However, I don't think the 11-11.4 is necessarily correct: I know that a lot of older detectors used a 11.558 Ghz 1st LO...

    Jim

  9. #9
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    Default

    Quote Originally Posted by jimbonzzz
    On this page it says 11-11.4 Ghz, and 13-15 GHz:
    http://www.radarbusters.com/support/...-detectors.asp

    However, I don't think the 11-11.4 is necessarily correct: I know that a lot of older detectors used a 11.558 Ghz 1st LO...

    Jim
    I forgot all about that Jim. Thanks for getting me back on track...and those are pretty narrow bandwidths. Good thing it doesn't cover the full spectrum, like from 11 to the 34s.

  10. #10
    Yoda of Radar
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    Default

    More or less everything said previously is correct. The only current proven Spectre-proof fix is to make a wavebox-filter that doesn't let singles under 20GHz from passing outwards. Unfortunately, this means the reverse is also true - so you have zero detection on X and Ku bands. K and Ka shouldn't be negatively affected to a huge degree.

    There is the general trend today to increase the LO frequency closer to that of the Ka spectrum, as most alerts are Ka. This will give a greater gain on Ka, since there is less heterodyning. Note that the first superhet detectors were set with LO around the frequency of X band, and have gone upwards gradually, with a big prod around 1995 to the current 13-15GHz range to beat VG2.

    This is generally the problem. If all detector companies made a different LO range on their RD models we would be better off. For example, a V1 would run at 20GHz, a Whistler Pro-666 would run at 25 and the Pro58 at 26 etc from around 10GHz to maybe 50GHz. Such a huge band would give an RDD a very poor performance.

    An RDD doesn't produce any leakage enough to alert one's detector. The exceptions are detectors with VG2 "cloaking" to VG2's, and Spectre-cloakers to Spectre I's. It won't come up as a typical X/K/Ka alert. Unfortunately.

    When the ESCORT came out in 1977, most every RD manufacturer switched to the superhet design of the ESCORT, keeping the same LO frequency. The first RDD, the VG2 designed by Techsonics Industries in Ontario, looked for this same frequency, and a slight range around it. Worked atreat. Whistler put a detector of the VG2's LO and integrated it into their units. It worked very poorly. However, Beltronics just shoved their LO upwards and became VG2 proof. Word got around and everyone did it. Techsonics tried widening the range of the VG2 however it just falsed too much.

    Spectre came out about 5-6 years later, and looked for all the freq's. Cobra tried shifting their LO upwards as well, and Stealth Micro Systems, Pty. just widened the band of the Spectre.

    You could say, the Spectre is a lot more upgradeable than that damned Valentine One! :x

 

 

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