6k7 vs. 6k6

DJ1WT

What is the reason for the differente in test Resultat measured by Rob Sherwood? Rolf

Johan / SE3X

Use Google, read some reports. And you will be enlightened. 

HCampbell WB4IVF

Rolf -

Here is a discussion including comments from Rob and Flex:

https://groups.io/g/FlexRadioSmartSDR/topic/19203177?p=,,,20,0,0,0::recentpostdate%2Fsticky,,,20,2,0,19203177

Howard

Johan / SE3X

Says the one that don't even display a call sign. Crawl back under your stone mr unknown

DrJ

My unintentional omission. You sir are aka a “keyboard commando”. I’ve seen and personally encountered many of your type. You mouth off and are rude to those who for some reasons unknown you feel you have a right to humiliate or feel “better than”. I know for certain you wouldn’t do this to me if you were in my personal immediate space. Most definitely. I suspect you wouldn’t and couldn’t do much about anything if I’m most persons immediate physicality. This person who posted a legotamte question to a forum in the attempt on utilizing the knowledge base of a group with dedication and consolidation of expertise on Flex radios. You had to be a “rear end” and answer with a passive-agreesice answer. I called you out on it. My address is accurate and up to date. During my years of service and dedication to my other principa hobbies and current passions , I most definitely and personally invite you for a more face to face meeting if you wish. I merely occasionally speak up for those feel intimidated by your types when in reality changes are you are out of shape, mesomorph with multiple medical issues that prevent you from defending your honor or your manhood. I don’t have a “rock” to crawl our from but I would invite you here to speak (or whatever form of communication is necessary) to get my point across to you. Stop picking on people and we’ll intentioned posts! My call is KJ8DO.

Johan / SE3X

No point continue this. You don't get it, never will. Your insults and comments just speaks for it self, as the person you are.

DJ1WT

Thank you, Howard! For several month I tried to find it out talking with the two German dealers. And 'googling' here in Germany was not successful. A nice monday for all, Rolf

DrJ

Au’ Contraire’. It is you that do not get it. The only possible excuse you could have is the possibility of your poor translation skills to English and (hopefully) the unintentional predatory context in which you communicated. However that theory was negated by the fact of your repeated responses in which I asked you to not “ridicule” an earnest question from the original post author. Your repeated defiance to me yet your repeated unwillingness to entertain the possibility of a “I apologize for what may have appeared to be inappropriate response” or something remotely similar. Instead you merely told him to “go google it and be “enlightened”. An obvious attempt to try and make yourself seem superior in your own ego/superego and it was a true fail. Basically my message to you and to all who respond to authors who post legitimate and well intentioned questions no matter how simple it may be to you, is to not respond (****) or offer a simple answer (see HCambell WB4IVF answer—-a simple, polite reference for a citation. All done and done with class no matter if he felt it was an appropriate question or not). Your persistent insults to me are proof positive of my point. You were called out in your behavior, and your less than ego is even more bruised. I for one and done putting up with the rude bahavior from people on line or anywhere else for that matter. Especially in the places (virtual or reality) that I go to to either enjoy my various hobbies). You are a troll, a bully and the equivalent of a QRMer online. In my response today I offer the only explanation for your repeated insults to me that I could conjour. If I remain inaccurate as to the reasoning of your original intent and if I “don’t get it” , PLEASE, explain to us all WHAT it is that I do not get. If I owe an apology, you will get one. But i remain convinced that you are an online bully, who in real life would shrink in front of any real man and dare not respond with the same condescending response you originally did in your first (and subsequent posts). I still maintain this. Correct me and all of us if I am wrong and a public and heartfelt apology will be forthcoming from me. Until then ,........ Keith Javery KJ8DO

DrJ

Glad that you got help from a gentleman! Good luck and 73! KJ8DO

Johan / SE3X

I think you would, in many ways be surprised, if our roads crossed. And I find your insults showing more of you being, quote " a troll, a bully and the equivalent of a QRMer online." I say with your writing you more and more prove you are the one you describe.

I'll leave it at this, I wont make more coments. It's useless and wasted energy. 

Matt NQ6N

In reading the information on the Sherwood ranking difference, it seems that the difference is attributed to variance in actual specs across multiple samples of the ADC part. 

I also read that there is not actually a need for a heat sink on the ADC chip, and that the heat sink was added in the first place to help with temperature stability, to make the calibration of the routine that uses the ADC more stable across varying temperatures. 

It was also mentioned that the calibration routine runs when the rig boots.

So my question is this:  Does the calibration routine run again once the rig is up to temperature, or periodically to adjust to shifts in ambient temperature which may effect the amount of residual heat on the ADC?

It would seem that since the ADC has constant heat dissipation, that if the rig was booted from room temperature and calibrated immediately, that the calibration result would be different than if the rig had been powered on for a few hours and then was simply rebooted/recalibrated. 

In the reboot case the ADC would already be very close to actual operating temperature when calibrated, whereas in the cold boot case the heatsink would be relatively cool and thus the calibration would run when the chip was a bit cooler than it would be after the rig had been running for a while. 

I ask this just out of curiosity because it has been something I've wondered about that I don't think has been covered on the forum posts I've read.  It seems logical that if the purpose of the heat sink is to stabilize the ADC thermally, that calibration would need to occur again after the heat in the system had stabilized, and that during a cold boot the sink and chip would be a lot cooler than they will be a few minutes later. 

73,
Matt NQ6N

DJ1WT

Matt, I'll try to find out how professional receiver (e.g. R&S) handle this problem. For me it is unsatisfying to buy a rig which is 'by luck' an excellent one. Average equipment I can buy cheaper...

Bill -VA3WTB

Mat, the ADC used in the flex is also used in other ways in many kinds of devices. In almost all these aplications a heat sink is not needed as the temp is not critical and the range for the ADC is wider. the chip will never be damaged from from not having a heat sink how ever.

But when this chip is used in the Flex radio, the chip must stay with in a critical range in order to perform as the Flex needs. If the heat sinks are removed in the radio many things go south, a very high noise floor is one of them.

As for how the radio makes adjustments from cold to warm I don't know, but it must.
Perhaps Steve will talk about this some time when he has time?

AA0KM

DJ1WT

Would an 'traditional' temperature compensation be an improvement? As this community has accumulated a lot of knowledge and experience I have another question being interesting perhaps to all: in the production process of chips, the output is not uniform in quality. I've been told that those chips of lower quality (matching the specs more or less) are sold at lower prices. Can this be a reason for the variance in test data of rigs Rob has measured? Rolf

Bill -VA3WTB

It is clear not clear to me that a cool chip performs differently than a warm one, and by how much? We do know that once the chip gets to warm, the Flex does not perform well.  When we start up our radios do we notice a performance difference at startup compaired to 15 minuts warmup? If you can, you would notice a higher noise floor at startup then as is warms up the noise floor decreases.

It is also important to understand that the differences in numbers make no difference in real world operation of the radio. in other words to us they would both perform the same.
Rob would need to test several radios to see how much difference there is between them instead of a one off that he does per test.

When Flex was in the designe stage they shopped around for the parts they needed that would perform to the standereds they set. This is why they were able to make 4 new radios very competitive in price where no one has been able to match.

It seems unlikely that by selecting components much more expensive performance would improve. Unless we are talking about processors. In that case Flex waits till a processor comes down in price before considering using it. Some new processors cost so much that they can not be considerd.

DJ1WT

I think FRS should help to clarify these things, it's their business. Rolf

Bill -VA3WTB

Here is a very good talk by Steve Hicks
https://www.youtube.com/watch?v=DvI7a1ka0TM

Ken - NM9P

It isn't by luck, but the ADC chips used in the SCU must be cooled by a heat sink.  This is not because they would get so hot that they risk damage to the component, but because if the chip temperature rises above a certain temperature the noise figure and other performance stats of the chip will be affected.  

Some of the early 6400 & 6600 rigs were supplied by the chip manufacturer with heat sinks whose adhesive failed.  When the chips dislodged, their performance was affected.

The fix required new heat sinks to be attached to the other side of the board with new adhesive.  These new heat sinks now keep the ADC chips well in their proper operating zone and this is no longer an issue.  Period.

Production problem solved.  Early rigs have been repaired.  No luck involved.

Bill Roberts

BTW, the Icom 7610 had a similar heatsink detachment issue.  Because there is no vendor sponsored community, this was not immediately reported or dealt with.  As a 6600 owner since May 12th (manufactured after the defect was uncovered and resolved in production), I remain thankful that Flex provides this Community.

Bill -VA3WTB

Yes here on this community you can see people post in real time and reply in real time, unlike an email based product group. This community helped put Flex on the map.

Bill -VA3WTB

Lookout,,Scam
Unrelated to Flex radio.

DJ1WT

As I've understand Rob tested updated versions of the rig, so why is the 6k7 so much better? Or do we have to live with such variances? And we would see them in a test of another 6k7-sample too? And are those variances accepted in professional equipment too? Ok, I accept that a receiver which costs 1/10 of the price of a professional one is not of the same quality. But I would like to see this in the specs. And thank you Rob for your work!! These data make such discussions possible. Rolf

VK7WH Winston

SPAM

David Decoons, wo2x