3.826 to 3.864

[Sajin]

Looking for more opinions.

Please explain why you selected Yes or No.

Thanks,

Sajin

[speed-dreams]

Because of digital temperature compensation. if it throws an E on the bogey counter, you know it needs to be calibrated.

[hockey005]

not worth the $85... get a tune which is only $45....not worth the whole temperature thing in my opinion..i have a 3.826 and my dad has a 3.863 and i cant tell the difference..

[Freebird]

Im new to the V1, could someone explain the digital temperature compensation tech in the new version (what the Heck it does)

Also without starting a new thread, whats a J-out, and in what modes A,L, or little l will I see that?

[GTO_04]

My 3.826 has served me well. If you need one, your tuneup is ususally no charge. I have yet to be charged by VR for a tuneup. The last time I sent a BEL in the charge was $85!

GTO_04

[mountainman]

Im new to the V1, could someone explain the digital temperature compensation tech in the new version (what the Heck it does)

Also without starting a new thread, whats a J-out, and in what modes A,L, or little l will I see that?

I beleive but im not sure that the E is from over heating, but J stands for "junk" on Ka band. I've gotten one J and it was some old timer in a pickup with a cobra or something. You can turn the Ka false J off but I wouldnt recomend it.

[<<JAZZY>>]

Im new to the V1, could someone explain the digital temperature compensation tech in the new version (what the Heck it does)

The V1 has used "digital processing" ever since it's introduction, so I'll assume you're asking about the differences between the pre-3.851 V1's (QJAV18) with "analog temperature compensation" vs the 3.851 and later (QJAV18A) with "digital temperature compensation".

The most notable difference is the addition of the "digital temperature compensation board" in the QJAV18A. This board samples the first LO and divides it down so that it can ultimately be compared to a reference. Then, the 1st LO can be adjusted or "calibrated" accordingly. This is to compensate for temperature, and also components which might change value slowly over time ("aging").

The previous version QJAV18 w/ analog temperature compensation most likely used a negative temperature coefficient capacitor somewhere in the circuit, to compensate for the rest of the components which most likely have a positive temperature coefficient (where resistance rises with temperature).

I'm sure the analog method wasn't completely linear, so the new method would definitely work better in that respect. Since the oscillator basically stays calibrated, there probably isn't as much oversweeping to be sure the police radar bands are covered when the oscillator drifts during normal operation. Of course, this has a positive effect on performance, probably not a large difference though.

Another benefit: the new digital compensation makes it much easier for the V1 to recognise when there is a problem. For example, if components fail or age causing it to go out of tune beyond what it can adjust, it will know this and throw and "E". Although the previous units could sometimes throw an "E" under some conditions, they didn't have the ability to monitor the 1st LO directly like the new ones do.

so the older V1 can overheat and not work you just dont know it ? but the new temp card lets you know now ?

Previous V1's had analog temperature compensation, the new ones have digital temperature compensation. So, the old ones should alert you too.

When you say "compensation", does the temperature affect, for example, the frequencies detected? For example, on a cold day, it detects 34.340Ghz, but on a HOT day it might detect 34.510Ghz (just as an example)?

Yes, without compensation, things similar to what you described could occur. Historically, detectors have swept a wider bandwidth to compensate for this (perhaps a few hundred MHz of the edges of the Ka band in some units), so that nothing in the police radar band was missed because of oscillator drift. But, there's drawback to this: as we know concentrating the sweep to signals of interest has an advantage in sensitivity. So, extra sweeping is undesirable. Hence, the Belscort's self-calibrate every so often during operation (they won't display Self Cal uness it starts to be a problem). I'm guessing V1's temperture compensation helps with this too.

I won't pretend I know any real details about it because I don't. But, I'll make some guesses anyway....

Temperature compensation probably helps control the oscillators, or possibly also filtering (we're talking RF filtering here) used for suppression of sidebands during the mixing process, or other circuits. The circuits might change a predictable amount due to temperature, and must be corrected for optimum performance.

With the old design, the unit probably took an analog temperature signal and fed it into a comparator or something, the output of which was used for correction. With the new design, perhaps digital temperature information is provided to a processor, and an algorithm is used to determine the amount of correction. Using an algorithm, one would be able to exercise much more control over the "corrections" than would be practical with an analog circuit, especially if the change isn't especially linear.

Jim

[Blown Z]

I have 3.826 and so far it has been flawless.

[Cips]

I voted yes. When I can, I like to have the newest most up to date things.

[crazyVOLVOrob]

If it not broke don't fix it.


Honestly the .826 is great version