Whistler PRO78 in conjunction with BEL v995 (w min interf)

[pronacyk]

I am using the Whistler PRO78 AND the BEL v995 in the same car and at the same time. Go ahead, poop your pants and call me a vile sinner for I have just broken the biggest RD commandment.

But wait.

Here's the data per FCC testing:

Whistler PRO78/XTR690's radiated emissions freq: 11.709GHz
Beltronics V995 (using RX65 as ref) radiated em. freq: 12.180GHz

Now, from what I understand (read: don't really understand), the reason why two radar detectors should never be operated in the same car is due to the fact that the upper harmonics of either detector would be in the K or Ka sweep range of the other, thereby causing the other to possibly filter out legitimate signals. Also, the overall noise floor would be raised on both detectors due to their radiated emissions, decreasing the SNR ratio (and detection range).

Is what I just stated true or partially true? If not, please feel free to correct me.

OK, back to some data. The first harmonic of both of detectors is well outside of the K-band sweep The second harmonic of the 78 is towards the high end of the Ka-band sweep (35.128) while the V995 is outside of the Ka sweep (36.540).

Here was my idea:

The PRO-78 will be assigned to sweep Ka-band only (X and K disabled) while the V995 will be assigned to sweep K-band only (X and Ka disabled). The PRO-78 will see a slight improvement in the ~10% narrower total sweep while the V995 will have a ~90% narrower total sweep. By having one detector not sweep the potential interference-prone bands of the other, would this minimize interference? There will still be a slight increase in overall noise floor. However, would the increase in sensitivity in the narrower sweep outweigh the decrease in SNR?

Major Assumption: Disabling band on the 78 and 995 prevents sweeping of the band.

Michael B and others, would you please comment on the validity (or invalidity) of my statements?

Thanks!

[pronacyk]

I just read a response to a similar thread from jimbonzzz (the professor) which just nullified this idea.

From what he said, turning off a band in most detectors just turns off reporting and not the actual sweeping (unless they are specifically designed to do so such as the rx65's Ka INTL to USA). It does not disable the LO's either, so they will still interfere behind the scene.

Guess I should make better use of the search feature next time :\

[Michael B]

Firstly the data you have from the FCC is meaningless to the respective products.

The FCC has to sniff from 11.7 to 12.2 ONLY for all radar detectors and report the highest recorded level within that freq range as part of their test. They do not go looking for the frequency where the units actually operate.

This highest level between 11.7 and 12.2 is then recorded. If it is above the maximum allowed, it is rejected.

To pass this test, all manufacturers have moved their LO to a frequency OUTSIDE the 11.7 to 12.2 window therefore there is nothing to detect.

The FCC must document the highest level recorded intheir scan of 11.7 to 12.2 even if it is the floor noise of their equipment.

[pronacyk]

Thanks for the clarification. I thought that the given freq was resonant frequency rather than just the peak within a certain band.