Superwide Band Ka: Strategy changed from early plans

[karl56]

Guys,

I remember when Ka/Wide/Superwide band was being released in early 90's and the inital report (with SW Ka) was that the possibility that the police radar units would have the capability to easily change the frequency slighty within the unit to make it difficult for detection. In other words, the entire SWKa spectrum was wide open.

I have not kept up with the changes in KaSW band operation over the last 13 years, but reading many posts on this forum, it appears that Ka is operated in only 3 frequencies within the SWKa frequency range allotted by the FCC for police radar? Is this correct?

Any comments/observations appreciated.

[djrams80]

In the US, only 3 Ka frequencies are used, 33.8 GHz(MPH), 34.7(Stalker) and 35.5(Decatur and Kustom). None of these change frequencies within the band. I think the proposed multiple frequency guns cost too much to manufacture.

[parasonic]

Not only are wideband varactor-tuned gunn oscillators expensive, but having a "frequency hopper" which could also potentially detect ranges would have a potential hurdle of needing to be proved to the courts. With the added cost and that issue, and some others, it just wasn't all that feasible.

There are other ways to build an oscillator, but the (edit: fixed-frequency) gunn homodyne transceiver is simple, it works, and it is easy to back up.

[amoney]

As said before, nothing became of it, all that there is, is three Ka freq, for whihc detectors must scan a wide spectrum, it was thought that detectors would be incapable to scan this full spectrum efficiently and reliable be able to detect radar. But that is not the case. Actually Beltronics has a more specific mode that scans only the three Ka frequencies and not the additional freq in between. This use to be called Ka Narrow, but now is referred to as USA mode for the 3 popular/only Ka frequencies, note that around the world the Ka frequencies vary, hence the USA mode specific for 33.8, 34.7, 35.5

:wink:

[karl56]

Thanks for the info.

As far as scanning the entire KaSW frequency, it seems like you are saying Bel scans for only those 3 frequencies while all other RD scan the entire allocated SW Ka band?

[amoney]

Thanks for the info.

As far as scanning the entire KaSW frequency, it seems like you are saying Bel scans for only those 3 frequencies while all other RD scan the entire allocated SW Ka band?

Yes but dont let that convince you it is far superior. The difference is neglegable, the processor scans throught the SW freq so fast there reall is no difference.

Not to get side tracked, but one reason one may not choose to use this mode is that if by chance if either particular equipemnt such as your RD or the officers radar gun was out of tune by a greater degree than acceptable, if in USA mode the signal may fall out of the scan and you would not get a alert. The full SW scan insures catching the signal, and as mentioned there is no noticable difference in performance. This theoritical was started when people (me included) noticed the tech mode (frequency display) showing up far out of normal range +/-, no this does not mean much because it is not like the tech mode (freq display) is supremely accurate.

To end with, there has never been a known problem using USA mode as many do use it.