Author Topic: Davis still using the CC1021 in current VP2 and/or VUE hardware?  (Read 2050 times)

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Offline miraculon

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There has been a lot of discussion in other threads about reception of the VP2 vs VUE hardware.

The Texas Instruments datasheet for the CC1021 has a red "Not Recommended for New Designs NRND" at the top of each page. (NRND is an abbreviation for the Not Recommended for New Designs, sounds kind of redundant...)

I was browsing through TI's RF transceiver offerings, to see what is newer. I noticed that the CC1021 is -109dBm and all of their other offerings are better than -116dBm. The CC1021 is also the lowest data rate. Obviously, TI still supplies the part but it appears that there are newer options.

I didn't do an exhaustive search in capabilities, but it seems that there are parts listed on this page that could replace the CC1021. (the pin counts are lower on some of these newer parts, which is typical but precludes "drop in replacement")

Has anyone opened a recent Davis console or SIM and looked at the RF chip? Are they still using the CC1021 across the board? My consoles/Envoys/SIMs are getting "long in the tooth" and probably have the CC1021.

I was wondering if the VUE might have gone with one of the newer parts with better sensitivity.

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Offline Old Tele man

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #1 on: January 13, 2018, 03:39:58 PM »
There has been a lot of discussion in other threads about reception of the VP2 vs VUE hardware.

The Texas Instruments datasheet for the CC1021 has a red "Not Recommended for New Designs NRND" at the top of each page. (NRND is an abbreviation for the Not Recommended for New Designs, sounds kind of redundant...)

I was browsing through TI's RF transceiver offerings, to see what is newer. I noticed that the CC1021 is -109dBm and all of their other offerings are better than -116dBm. The CC1021 is also the lowest data rate. Obviously, TI still supplies the part but it appears that there are newer options.

I didn't do an exhaustive search in capabilities, but it seems that there are parts listed on this page that could replace the CC1021. (the pin counts are lower on some of these newer parts, which is typical but precludes "drop in replacement")

Has anyone opened a recent Davis console or SIM and looked at the RF chip? Are they still using the CC1021 across the board? My consoles/Envoys/SIMs are getting "long in the tooth" and probably have the CC1021.

I was wondering if the VUE might have gone with one of the newer parts with better sensitivity.

Greg H.
Anybody got an open VUE pcb where its components can be viewed?
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Offline rdsman

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #2 on: January 13, 2018, 04:08:18 PM »
The VUE console uses the CC1101.  Not sure about the VUE ISS.


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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #3 on: January 13, 2018, 04:12:12 PM »
The VUE console uses the CC1101.  Not sure about the VUE ISS.
Q: On a VP2 ISS, is it U41 or U21?
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Offline ValentineWeather

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #4 on: January 13, 2018, 04:24:31 PM »
So 109 dBm on VP2 vs 116 on Vue. If correct could be the cold weather mystery answer.
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Offline johnd

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #5 on: January 13, 2018, 04:47:41 PM »
So 109 dBm on VP2 vs 116 on Vue. If correct could be the cold weather mystery answer.

Just chasing that potential pink herring, then that would imply that the ISS signal was getting weaker in very cold conditions, which should have been evident from the RSSI figure**. Maybe openvista could eyeball some relative RSSI values (from the 2nd diagnostic screen) from VP2 vs Vue console. Of course it's slightly complicated with the Vue and VP2 being on different but related scales.

Must admit that I always think better on the VP2 scale, preferring to see RSSI≥30 for decent reception. I once worked out that:

VP2 = [(Vue + 100) / 1.5] + 20

Hopefully that formula is correct. In other words, the Vue ought to be -85dBm or better (less negative). But maybe the Vue is a bit more tolerant then and -90 or even -95dBm might be adequate. (Edit: Yes, those RSSI figures are quite a bit stronger than the threshold sensitivity, but I've never seen a VP2 console reliably pick up an ISS at less than low 20's RSSI or eg -92dBm, so obviously there are other factors like background noise involved.

** Really should have thought to ask the RSSI question at an earlier stage in the troubleshooting - grey cells must be dying off quicker than I'd like to think. :-(

And, one other afterthought: What I'm thinking about is looking for differences in RSSI between 'normal-reception' and very cold conditions to see if the transmitter really is getting weaker.
« Last Edit: January 14, 2018, 08:55:04 AM by johnd »
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Offline rdsman

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #6 on: January 14, 2018, 11:59:02 AM »
Quote
Q: On a VP2 ISS, is it U41 or U21?

U41...

Ray

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #7 on: January 14, 2018, 02:40:28 PM »

Anybody got an open VUE pcb where its components can be viewed?
A guy here is fixin' to change out a supercap on the Vue. http://www.wxforum.net/index.php?topic=33576.0
 From the picture with the cap exposed I can't see how easy it would be to get to the other components.

Offline openvista

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #8 on: January 15, 2018, 11:54:05 AM »
Maybe openvista could eyeball some relative RSSI values (from the 2nd diagnostic screen) from VP2 vs Vue console.

Sorry, just saw this thread now.

Over in the other discussion on signal dropouts (https://www.wxforum.net/index.php?topic=33496.150) I had noted that the average RSSI on my VP2 console for the ISS was upper 50s and for the wind was mid 40s. Given that 60 is the theoretical maximum value, that would equate to above average to near perfect signal strength for both transmitters.

On the Vue the ISS reception averages upper -60s (dBm) to low 70s and the wind transmitter averages mid to upper -70s when its 10F or colder. So the Vue would seem to indicate the overall signal quality is actually worse (scale from 0 to -100 where 0 is the strongest signal), but still well within the range of connectivity.

A complicating factor is that when it's really cold, and the VP2 console disconnects from, for example, the ISS transmitter (the closest, strongest signal), often it won't reconnect unless you manually throw the VP2 console into setup mode (or, according to ValentineWeather, use WeatherLink to reset). This is despite the fact that the console attempts to reconnect automatically every 15 minutes. Even stranger is that if you let the outage go long enough (several hours) eventually the console will reconnect. Yet, I've always been able to get it to reconnect immediately if I place it into setup mode.

One would assume that the wind transmitter would be subject to the longest outages since it's the furthest transmitter and measures weaker in both consoles. However, while its outages tend to be more frequent, they typically don't last nearly as long (minutes) as the ISS outages (hours).

Also, I've never lost both transmitters' signals simultaneously. If this problem is the result of poor signal strength in cold weather, why would one transmitter always stay connected regardless?

So, it would seem that the VP2 console outages aren't simply due to signal sensitivity. There would seem to be some firmware issues in play too.
« Last Edit: January 15, 2018, 12:11:00 PM by openvista »
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Offline ValentineWeather

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #9 on: January 15, 2018, 02:42:33 PM »
Doubt it would be as simple as firmware when the hardware RF chips actually have different dB sensitivity with the Vue 116 vs 109 on VP2.
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Offline openvista

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #10 on: January 15, 2018, 03:08:53 PM »
Doubt it would be as simple as firmware when the hardware RF chips actually have different dB sensitivity with the Vue 116 vs 109 on VP2.

I didn't say it's only firmware. But if it's purely signal sensitivity, why does throwing the console into setup mode so often fix it? And why doesn't the console find the signal when it goes to automatically reconnect every 15 minutes? Either way an "R" flashes in the lower right. Both actions are handled by the firmware.

Also why does the console drop the strongest signal while keeping the weakest signal online for hours at a time? Why does it never drop both?
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Offline rdsman

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #11 on: January 15, 2018, 03:23:14 PM »
Perhaps the VP2 is only compensating for one of the transmitter's frequency error.  It keeps doing this until the other transmitter can no longer be received.  Placing the console in Setup does away with the acquired frequency error data and allows it to reconnect with both transmitters.



Ray

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #12 on: January 15, 2018, 03:25:51 PM »
Considering that the magnitude of this problem seems to only be coming to light fairly recently, while the VP2 has been in wide use for around a decade and a half, I wonder if any one can show if the problem has existed all along or when it appeared.  Looking at the other thread, I see graphs showing the problem has been around since at least October 2015.  The last firmware update appears to be March 2014. 
« Last Edit: January 15, 2018, 03:30:14 PM by SnowHiker »

Offline openvista

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #13 on: January 15, 2018, 03:30:19 PM »
Perhaps the VP2 is only compensating for one of the transmitter's frequency error.  It keeps doing this until the other transmitter can no longer be received.  Placing the console in Setup does away with the acquired frequency error data and allows it to reconnect with both transmitters.

Yes, but the firmware should do that automatically. Why require user intervention?

If it were the case that the console needs to clear all data from the display so it can dedicate its resources to reconnection, then why not set a limit like 3 failed resync attempts and then enter setup automatically?

Either way, our discussion is centering around firmware limitations.
« Last Edit: January 15, 2018, 06:33:58 PM by openvista »
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Offline SnowHiker

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #14 on: January 15, 2018, 04:41:33 PM »
Has anyone opened a recent Davis console or SIM and looked at the RF chip? Are they still using the CC1021 across the board? My consoles/Envoys/SIMs are getting "long in the tooth" and probably have the CC1021.

Looking over this thread again, I see where someone verified that the Vue is using a different chip, but unless I'm missing it, I don't see where anyone verified the newer VP2 consoles are still using the CC1021.  Unless someone verifies, I'm not sure we can just assume that they are and that that's the problem.  I suspect Davis tries to keep their component inventory and design differences between the different models as small as possible.

Who knows, maybe the problem became more noticeable when or if Davis switched to the new chips in the VP2.

Offline rdsman

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #15 on: January 15, 2018, 05:18:28 PM »
If Davis changed RF chips in the VP2, they didn't notify the FCC.........
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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #16 on: January 16, 2018, 12:03:44 AM »
If Davis changed RF chips in the VP2, they didn't notify the FCC.........
Are they required to report changes in the RF chip if the approved specifications aren't exceeded, or does every component change require retesting? 

I've found some docs like this: https://fccid.io/IR2DWW6312/Test-Report/Test-Report-474646, but I'm not finding where what RF chip is used is specified, and I'm not up on FCC requirements.

Offline rdsman

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #17 on: January 16, 2018, 09:05:18 AM »
If Davis changed RF chips in the VP2, they didn't notify the FCC.........
Are they required to report changes in the RF chip if the approved specifications aren't exceeded, or does every component change require retesting? 

I've found some docs like this: https://fccid.io/IR2DWW6312/Test-Report/Test-Report-474646, but I'm not finding where what RF chip is used is specified, and I'm not up on FCC requirements.

Title 47 CFR 2.1043(a) states in part:

Quote
changes to the basic frequency determining and stabilizing circuitry (including clock or data rates), frequency multiplication stages, basic modulator circuit or maximum power or field strength ratings shall not be performed without application for and authorization of a new grant of certification.

Ray

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #18 on: January 16, 2018, 02:31:52 PM »
If Davis changed RF chips in the VP2, they didn't notify the FCC.........
Are they required to report changes in the RF chip if the approved specifications aren't exceeded, or does every component change require retesting? 

I've found some docs like this: https://fccid.io/IR2DWW6312/Test-Report/Test-Report-474646, but I'm not finding where what RF chip is used is specified, and I'm not up on FCC requirements.

Title 47 CFR 2.1043(a) states in part:

Quote
changes to the basic frequency determining and stabilizing circuitry (including clock or data rates), frequency multiplication stages, basic modulator circuit or maximum power or field strength ratings shall not be performed without application for and authorization of a new grant of certification.
Thanks.  I guess that's more or less definitive.  Not being a lawyer and reading all the exclusions and such, I don't know if it can be argued that even though Davis changed a part (that I assume itself has an FCC ID, and could possibly be considered an acceptable replacement?), but all the ratings listed remain the same, that it doesn't require recertification.  If they did change the chip, it would assumedly still have the basic characteristics of the old units to remain compatible, as long as it doesn't exceed power or such.

Anyway, I doubt this is a chip problem.  The characteristics of the CC1021 didn't suddenly become inadequate when TI declared it NRND.

I could be wrong, the problem could have existed since the release of the VP2, and the correlation between the cold and dropouts just happened to be made fairly recently, as far as I can tell, despite the years in use and the popularity of the station.  It is possible, unexplained dropouts have existed all along.  Just seems that if that large of a percentage of units are affected as it would seem, it would have been apparent before now.

Just curious, has anyone compared the reception of an affected VP2 console from a Vue ISS?


Offline openvista

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #19 on: January 16, 2018, 08:13:23 PM »
I could be wrong, the problem could have existed since the release of the VP2, and the correlation between the cold and dropouts just happened to be made fairly recently, as far as I can tell, despite the years in use and the popularity of the station.  It is possible, unexplained dropouts have existed all along.  Just seems that if that large of a percentage of units are affected as it would seem, it would have been apparent before now.

Just curious, has anyone compared the reception of an affected VP2 console from a Vue ISS?

Yes, I made a detailed post on this very page (http://www.wxforum.net/index.php?topic=33638.msg341623#msg341623) comparing the VP2 console reception to the Vue.

As far as how old this issue is, here's a thread dated January 2014: https://www.wxforum.net/index.php?topic=21526.msg211815;topicseen#msg211815. Notice "cold" is only mentioned one time in that thread. It's framed as a battery problem even though the issue is occurring during a cold snap in the winter and he had replaced the CR123a battery just weeks before.

Mid-identifying the cause can be expected since the problem is counter-intuitive. Doubt is probably the most natural reaction to it. I doubted until I noticed I had received 2 out of 2 consoles 2.5yrs apart with the same issue). Searching for something people don't report or don't consistently describe is difficult.

Here are some other threads going back as far as 2009 that could be the same issue:
https://www.wxforum.net/index.php?topic=13811.msg134822#msg134822
https://www.wxforum.net/index.php?topic=6115.25
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Offline SnowHiker

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #20 on: January 17, 2018, 12:40:55 AM »


Just curious, has anyone compared the reception of an affected VP2 console from a Vue ISS?

Yes, I made a detailed post on this very page (http://www.wxforum.net/index.php?topic=33638.msg341623#msg341623) comparing the VP2 console reception to the Vue.


Maybe I'm missing something on the other thread, but my question is if anyone who has a Vue ISS and a VP2 console notes the same problem with reception from the Vue ISS that they do from the VP2 ISS.  I know you have a VP2 console, a Vue console and a VP2 ISS, are you saying you have a Vue ISS also?  People with VUEs probably don't have much reason to buy a VP2 console. I'm not sure what it would prove, but as I say, I was just curious.

Thanks for the other links I'll have to go back and review the other threads and see if there's any new clues there, thought I doubt it.  About the only way would be if everyone with a VP2 had records for the life it that showed what percentage of consoles have the problem, when it started or if had always been there to get some kind of an idea.  Either that, or everyone who experiences the problem try to get an answer and a fix from Davis.

Offline SnowHiker

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #21 on: January 17, 2018, 01:47:36 AM »
As far as how old this issue is, here's a thread dated January 2014: https://www.wxforum.net/index.php?topic=21526.msg211815;topicseen#msg211815. Notice "cold" is only mentioned one time in that thread. It's framed as a battery problem even though the issue is occurring during a cold snap in the winter and he had replaced the CR123a battery just weeks before.
The problem here is that the thread continues on into March when
The sky was blue, temp. 70, time 1:00PM, no excuse in solar panel not to carry the ISS.
which leads me to believe it's not the same problem, at least not entirely if at all.

Unfortunately, the thread ends soon after with no apparent resolution, unless maybe the station finally got over its frostbite. :-)

Offline openvista

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #22 on: January 17, 2018, 09:22:39 AM »
About the only way would be if everyone with a VP2 had records for the life it that showed what percentage of consoles have the problem, when it started or if had always been there to get some kind of an idea.  Either that, or everyone who experiences the problem try to get an answer and a fix from Davis.

As zackdog and I pointed out several times in the other thread, most people DO have a complete record of signal strength. It's in their WeatherLink archives. They can graph temperature and signal strength and see when those two lines correspond.

The question then becomes how many people live in an area that gets cold enough often enough to notice the problem and/or how many will check WeatherLink in the fashion described above? zackdog issued the challenge to everyone to check their records. How many people responded even if just to prove him wrong? My count is 0.

I'd bet the majority of Davis' customers have never even heard of WxForum. How many farmers have you seen on this forum?

As for those that do come here perhaps they don't want to be told it's only them, or it's only been happening recently, or they set their ISS up wrong, or they can't expect batteries to operate at 10F or that Davis would have fixed it by now or any of the myriad excuses those of us who have reported this issue have been given.

Yes, it's more likely those affected contacted Davis rather than publicly make their case, especially if they were uncertain what was going on.
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Offline johnd

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #23 on: January 17, 2018, 09:29:07 AM »
As zackdog and I pointed out several times in the other thread, most people DO have a complete record of signal strength.

Not really. They have a record of successful packet reception, which isn't quite the same thing as signal strength (RSSI). You can have a decent signal (say RSSI=30 or more for a VP2 or better than -85dBm for a Vue), but frequency or timing deviations that the receiver cannot lock on to or eg significant interference.

The RSSI information is available, just a shame that it's not logged.

Edit: Meant to add: This is pertinent to what I think may be happening with this low temperature issue. Your ISS signals look strong enough normally that I doubt they're weakening sufficiently to cause dropouts (though looking at the RSSI when dropouts are pending - but obviously before they actually happen - would help clarify that). I suspect that some other aspect of the signal profile is causing the problem, possibly that low temps are causing some drift in signal frequency or timing, which is outside the parameters that the VP2 console can cope with. Either the circuitry of the Vue is somehow more forgiving of the deviations or maybe it can recover much more quickly from any dropouts that do happen.
« Last Edit: January 17, 2018, 09:48:14 AM by johnd »
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Offline openvista

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #24 on: January 17, 2018, 09:44:31 AM »
As zackdog and I pointed out several times in the other thread, most people DO have a complete record of signal strength.

Not really. They have a record of successful packet reception, which isn't quite the same thing as signal strength (RSSI). You can have a decent signal (say RSSI=30 or more for a VP2 or better than -85dBm for a Vue), but frequency or timing deviations that the receiver cannot lock on to or eg significant interference.

The RSSI information is available, just a shame that it's not logged.

Well, if you see packet reception drop to nothing for a period -- graphs that ValentineWeather and zackdog have posted several times -- it's safe to assume that there is no connection between receiver and transmitter. Those periods just happen to correspond to cold weather.

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