Author Topic: Davis still using the CC1021 in current VP2 and/or VUE hardware?  (Read 2451 times)

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Online openvista

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #25 on: January 17, 2018, 02:30:46 PM »
Here's what has been put together in two separate threads so far through a combination of first-hand testimony and statistical data:

1. We have graphs connecting total loss of signal to cold temperatures starting around 10F (give or take 5F).
2. We have visual confirmation of the outage on VP2 consoles during at least some of these periods (others occur in the wee hours of the night or when the owner is otherwise away).
3. We know it occurs across various vintages of transmitters and consoles (going back to at least mid 2013).
4. The issue is not limited to particular channels.
5. The issue persists with new transmitter batteries.
6. Consoles can be moved to more favorable spots (based on reception statistics) and still experience reception difficulties despite being well within range
7. The reception problems disappear once a Vue console is acquired and placed in the same spot
8. The Vue console appears to have a different receiving chip than the VP2 with greater signal sensitivity
9. There appear to be some software routines in the firmware that at least prolong outages in the VP2 console.

All signs point to design error even if it's mostly component tolerances (meaning some owners experience it and some owners don't despite having "identical" components). If it's truly reception based, as this thread would suggest, then it would follow that certain owners in favorable RF environments (combination of close proximity and lack of obstacles) might not experience it while others would.

For those who do, they also need to live in a qualifying climate, observe the issue, feel motivated to solve the issue (rather than let it go because it may happen infrequently), then have the confidence to go public with their problem. If any of those aren't true, we almost certainly won't know about it.
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Offline SnowHiker

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #26 on: January 17, 2018, 03:00:50 PM »

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.
This forum has been a very active forum for many years, and I would think most people live where the temp at least periodically gets down to 10 degrees.

If people aren't reporting the problem, its probably because they're not experiencing the problem.  The lack of response to Zackdog's challenge helps back that up.  People, especially the less interested and involved, are less likely to follow and respond to a thread about a problem they aren't having. I recall at least one person saying they don't have the problem.

People don't necessarily even have to have WeatherLink.  Most people do seem to connect to their computers and/or the internet, and do diligently check their data for any anomalies. Nightly winter lows are especially things people look for and would notice.  Even if other software shows flatlines rather than blanks, they're still going check that out, especially as it would be happening to all weather variables and presumably would stick out. 

People do try to help each other out here, and that often involves speculation, ideas like lithium batteries can't be expected to operate below 20 are considered and discounted.  What you are calling "excuses" are people trying to make sure common errors aren't being committed. That is a reasonable, and even necessary, aspect of troubleshooting. When people suggest someone looking for help check certain things, I don't see it as being accusatory, or as definitively stating that that's what the problem is.

People are looking for evidence and correlation to try to figure things out.  If I speculate that the problem seems to have become more apparent recent years, and no one presents any compelling evidence to the contrary, I don't see why that should offend anyone.  Others have stated that they don't experience the problem, so however widespread it may be, it doesn't appear to be universal, despite however it may look to you.  Of the links you gave earlier, I saw one case were there appeared to be direct evidence that there was a link to dropouts and the cold.  Even then you need to consider whatever incidental factors there may be; such as cold happening to coincide with the longest nights, or such.  Despite all that, I'm not trying to minimize or deny the problem to those who do experience it.

You came here looking for answers, yet don't seem to appreciate ideas and speculation of what the problem may be.  You seem to believe that Davis knows about the problem, with no evidence, and even if they don't, they're still guilty, and that they're the only ones who can solve the problem. Well, you're most likely correct about the last point at least.  But as someone else has said, you're unhappy with Davis, but won't tell them.  So you've presented your evidence, and I think it is pretty conclusive and valuable.  Unfortunately, at least so far, it doesn't tell exactly what is causing the problem, or how widespread it is.
« Last Edit: January 17, 2018, 03:03:38 PM by SnowHiker »

Offline johnd

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #27 on: January 17, 2018, 03:48:51 PM »
Here's what has been put together in two separate threads so far through a combination of first-hand testimony and statistical data:

1. We have graphs connecting total loss of signal to cold temperatures starting around 10F (give or take 5F).
...
8. The Vue console appears to have a different receiving chip than the VP2 with greater signal sensitivity

I'm still going to quibble with [1]. I don't believe that there's evidence that it's a loss of signal strength, but a loss of signal lock/synch. You may think that it amounts to the same thing, but there's a different cause in each case and a loss of lock isn't explained by superior sensitivity of the Vue console (though a different receiver chip, if there is one, might have other benefits). OTOH there are other conceivable explanations, eg maybe the simpler transmitter spec of the Vue allows a simpler search pattern in the firmware for resynchs and hence quicker resynchs..

The question then becomes how many people live in an area that gets cold enough often enough to notice the problem...

Probably not many outside of the US (excluding much of the south) and Canada I'd have guessed. The main exception in Europe would be Scandinavia and around the Alps (and Eastern Europe too, but probably not too many Davis stations there). But here in the UK, for instance, which is hardly a warm climate, temperatures below -12C are pretty rare, certainly in all the main lowland areas where the great majority of the population live. So I'm unsurprised to have seen this rarely reported here.
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Offline ValentineWeather

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #28 on: January 17, 2018, 04:06:51 PM »
OTOH there are other conceivable explanations, eg maybe the simpler transmitter spec of the Vue allows a simpler search pattern in the firmware for resynchs and hence quicker resynchs..



This was something I was thinking also. But the less sensitivity may also play some roll.
Davis techs need to know about the issue and look into it. Hope someone has taken it up with them.
Randy

Offline johnd

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #29 on: January 17, 2018, 04:12:22 PM »
But the less sensitivity may also play some roll.

But there's no evidence that I've seen cited anywhere that the signal was weak (on the contrary what openvista reports AIUI is that the signal was relatively strong prior to dropout) and so why would greater sensitivity at the margin make any difference?

But what I'm debating here is the technical cause of the apparent issue and not whether or not Davis should be engaged, if anyone should be motivated to do so.
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Offline CW2274

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #30 on: January 17, 2018, 04:21:28 PM »
Hell, I don't even have a dog in this fight, I'll call Brett Lane myself. Whether that helps or not....

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #31 on: January 17, 2018, 04:28:45 PM »
Message sent.

Offline SnowHiker

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #32 on: January 17, 2018, 04:29:18 PM »
The question then becomes how many people live in an area that gets cold enough often enough to notice the problem...

Probably not many outside of the US (excluding much of the south) and Canada I'd have guessed. The main exception in Europe would be Scandinavia and around the Alps (and Eastern Europe too, but probably not too many Davis stations there). But here in the UK, for instance, which is hardly a warm climate, temperatures below -12C are pretty rare, certainly in all the main lowland areas where the great majority of the population live. So I'm unsurprised to have seen this rarely reported here.
Yet there are many here, seems like a fair percentage actually, from northern US states, along with at least some from Canada and regions such as Norway.  For every person commenting about their stations bottoming out or not at -40, you would think there would be at least a few others noting a problem that occurs at +10F.  Plus, stations are said to be used in Antarctic research, I believe it's been claimed.  While they don't post here, as far as I'm aware, you would think that such a problem with equipment being used by, I assume, scientists for scientific research would be noted by now.

[BTW, the quote you attributed to me was originally from OpenVista.]

Offline rdsman

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #33 on: January 17, 2018, 04:37:39 PM »
I have one simple question:

The Vue has a Reception Diagnostic Screen (Screen 2) that shows the Current frequency correction factor.  Does it do it for both of the transmitters or only one, or can you somehow choose which one to monitor? 

Ray

Offline johnd

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #34 on: January 17, 2018, 04:46:30 PM »
The Vue has a Reception Diagnostic Screen (Screen 2) that shows the Current frequency correction factor.  Does it do it for both of the transmitters or only one, or can you somehow choose which one to monitor?

Pretty sure you can choose - certainly you can on VP2 and it's usually the same on the Vue. Should be 2nd+Chill then left or right arrow to cycle through active transmitters (of which there will be 2 max on the Vue, but only when a 6332 Tx is being used).
« Last Edit: January 17, 2018, 04:52:12 PM 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 #35 on: January 17, 2018, 05:00:55 PM »
The Vue has a Reception Diagnostic Screen (Screen 2) that shows the Current frequency correction factor.  Does it do it for both of the transmitters or only one, or can you somehow choose which one to monitor?

Pretty sure you can choose - certainly you can on VP2 and it's usually the same on the Vue. Should be 2nd+Chill then left or right arrow to cycle through active transmitters (of which there will be 2 max on the Vue, but only when a 6332 Tx is being used).

Then my first test would be to see if the same frequency correction factor is being applied to both transmitters.  Or is it distinctly different values as it should be. 

Even TI's Design Note DN015 states:

Quote
Finally, note that in an RF network application each receiver should memorize the frequency offset value associated with each transmitting
node in order to apply the correct permanent offset when communicating with different nodes.



« Last Edit: January 17, 2018, 05:12:19 PM by rdsman »
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Online openvista

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #36 on: January 17, 2018, 06:12:18 PM »
Here's what has been put together in two separate threads so far through a combination of first-hand testimony and statistical data:

1. We have graphs connecting total loss of signal to cold temperatures starting around 10F (give or take 5F).
...
8. The Vue console appears to have a different receiving chip than the VP2 with greater signal sensitivity

I'm still going to quibble with [1]. I don't believe that there's evidence that it's a loss of signal strength, but a loss of signal lock/synch. You may think that it amounts to the same thing, but there's a different cause in each case and a loss of lock isn't explained by superior sensitivity of the Vue console (though a different receiver chip, if there is one, might have other benefits). OTOH there are other conceivable explanations, eg maybe the simpler transmitter spec of the Vue allows a simpler search pattern in the firmware for resynchs and hence quicker resynchs..



OK, fair enough.  We certainly appear to be having a syncing issue. I can see other possible benefits to the Vue console such as better processing and more complimentary, optimized firmware that prevents signal locks from breaking. Perhaps Davis learned from earlier failures.

Either way, we seem to have an issue that is baked into the console to one degree or another.

To the average affected VP2 user the solution is always going to be the same: get a Vue console. That is, of course, unless Davis spontaneously decides to redesign the RF section of their 13 yr old console. I'm not holding my breath.
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Offline rdsman

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #37 on: January 17, 2018, 06:30:29 PM »
Did you run the test that I inquired about? 



Ray

Online openvista

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #38 on: January 17, 2018, 06:42:36 PM »
Did you run the test that I inquired about?

I'm not sure if this question is directed at me, but I'll go ahead and answer. Yes, I ran the test. However, it's +31F (~0C) here now so this may or may not be the case at colder temps. I haven't really paid a lot of attention to this parameter other than to notice that it hops around on the VP2.

Indeed, there are discrete, navigable screens for each active channel. The frequency correction is 0 for both transmitters on the Vue console and holding steady. On the VP2, it vacillates between +1 and +2 for the ISS. The wind transmitter at one point was showing 1 and then later 3. The factors do not seem to correspond across channels.
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Offline rdsman

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #39 on: January 18, 2018, 08:38:26 AM »
Did you run the test that I inquired about?

I'm not sure if this question is directed at me, but I'll go ahead and answer. Yes, I ran the test. However, it's +31F (~0C) here now so this may or may not be the case at colder temps. I haven't really paid a lot of attention to this parameter other than to notice that it hops around on the VP2.

Indeed, there are discrete, navigable screens for each active channel. The frequency correction is 0 for both transmitters on the Vue console and holding steady. On the VP2, it vacillates between +1 and +2 for the ISS. The wind transmitter at one point was showing 1 and then later 3. The factors do not seem to correspond across channels.

Are you looking at item (2.)  Radio frequency error of the last packet received successfully.  Or item (3.)  Current frequency correction factor.  (Just checking.)   

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #40 on: January 18, 2018, 08:54:50 AM »
Did you run the test that I inquired about?

I'm not sure if this question is directed at me, but I'll go ahead and answer. Yes, I ran the test. However, it's +31F (~0C) here now so this may or may not be the case at colder temps. I haven't really paid a lot of attention to this parameter other than to notice that it hops around on the VP2.

Indeed, there are discrete, navigable screens for each active channel. The frequency correction is 0 for both transmitters on the Vue console and holding steady. On the VP2, it vacillates between +1 and +2 for the ISS. The wind transmitter at one point was showing 1 and then later 3. The factors do not seem to correspond across channels.

Are you looking at item (2.)  Radio frequency error of the last packet received successfully.  Or item (3.)  Current frequency correction factor.  (Just checking.)

Definitely frequency correction factor. Just re-checked both manuals and then both consoles. Those are the correct values.
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Online openvista

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #41 on: January 18, 2018, 08:56:53 AM »
Sorry, my bad. On the Vue console I was wrong. It's -4 for the ISS and -3 for the wind. The VP2 was correct.
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Offline rdsman

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #42 on: January 18, 2018, 10:27:48 AM »
Lets visualize this is a different manner.  Below is the output of a CC1101 receiving packets from an ISS:

Code: [Select]
Index: 00  Packet: A0  00  A4  81  1B  00  1F  0E  FF  FF  RSSI: -67  Correction: -22
Index: 01  Packet: E0  00  A4  80  01  00  AE  96  FF  FF  RSSI: -68  Correction: -20
Index: 02  Packet: 50  00  A4  FF  73  00  CF  38  FF  FF  RSSI: -68  Correction: -20
Index: 03  Packet: 80  00  A4  14  99  00  C4  35  FF  FF  RSSI: -70  Correction: -19
Index: 04  Packet: 20  00  A4  6D  C1  80  75  1A  FF  FF  RSSI: -66  Correction: -19
Index: 05  Packet: E0  00  A4  80  03  00  C8  F4  FF  FF  RSSI: -73  Correction: -20
Index: 06  Packet: 50  00  A4  FF  71  00  A9  5A  FF  FF  RSSI: -70  Correction: -20
Index: 07  Packet: 80  00  A4  14  79  00  D4  87  FF  FF  RSSI: -66  Correction: -20
Index: 08  Packet: 70  00  A4  8F  01  80  DD  8B  FF  FF  RSSI: -69  Correction: -20
Index: 09  Packet: E0  00  A4  80  01  00  AE  96  FF  FF  RSSI: -65  Correction: -19
Index: 10  Packet: 50  00  A4  FF  71  00  A9  5A  FF  FF  RSSI: -66  Correction: -21

Shown above is the Rx Hop Index (Channel), the actual packet, RSSI and the accumulated frequency error correction being applied for that channel.    This pretty much matches what my Vue console is showing.   So in openvista's case, the Vue console should be keeping up with both transmitters on a per channel basis.  A VP2 should be doing something similar.


 
Ray

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #43 on: January 18, 2018, 10:40:26 AM »
Lets visualize this is a different manner.  Below is the output of a CC1101 receiving packets from an ISS:

Code: [Select]
Index: 00  Packet: A0  00  A4  81  1B  00  1F  0E  FF  FF  RSSI: -67  Correction: -22
Index: 01  Packet: E0  00  A4  80  01  00  AE  96  FF  FF  RSSI: -68  Correction: -20
Index: 02  Packet: 50  00  A4  FF  73  00  CF  38  FF  FF  RSSI: -68  Correction: -20
Index: 03  Packet: 80  00  A4  14  99  00  C4  35  FF  FF  RSSI: -70  Correction: -19
Index: 04  Packet: 20  00  A4  6D  C1  80  75  1A  FF  FF  RSSI: -66  Correction: -19
Index: 05  Packet: E0  00  A4  80  03  00  C8  F4  FF  FF  RSSI: -73  Correction: -20
Index: 06  Packet: 50  00  A4  FF  71  00  A9  5A  FF  FF  RSSI: -70  Correction: -20
Index: 07  Packet: 80  00  A4  14  79  00  D4  87  FF  FF  RSSI: -66  Correction: -20
Index: 08  Packet: 70  00  A4  8F  01  80  DD  8B  FF  FF  RSSI: -69  Correction: -20
Index: 09  Packet: E0  00  A4  80  01  00  AE  96  FF  FF  RSSI: -65  Correction: -19
Index: 10  Packet: 50  00  A4  FF  71  00  A9  5A  FF  FF  RSSI: -66  Correction: -21

Shown above is the Rx Hop Index (Channel), the actual packet, RSSI and the accumulated frequency error correction being applied for that channel.    This pretty much matches what my Vue console is showing.   So in openvista's case, the Vue console should be keeping up with both transmitters on a per channel basis.  A VP2 should be doing something similar.

I see a difference of between 3 and 6 comparing corresponding channels across receivers over time. So, for instance, currently on the Vue, the correction factor for the wind xmtr is -3 but on the VP2 it's +1. That's a difference of 4. For the ISS, the Vue reports -5 and the VP2 +1. That's a difference of 6. The receivers are right beside each other.
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Offline rdsman

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #44 on: January 18, 2018, 10:53:40 AM »
So the objective here is to somehow prove/disprove that the VP2 does in fact track both transmitters independently.......

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #45 on: January 18, 2018, 11:10:23 AM »
So the objective here is to somehow prove/disprove that the VP2 does in fact track both transmitters independently.......

There can sometimes be a difference between the two channels' correction factors on the VP2 console. Usually it differs only by 1 but sometimes 2. So if the ISS is 1, the wind will be 2 or 3. Thus it would appear it is tracking them independently. Now, if you mean independently (a.k.a. differently) from the Vue, then yes, that, too, is true and might be a cause for concern.

It appears, if I understand this correctly, the Vue may do a better job finding the precise frequency of each transmitter which creates a better signal lock more resistant to being dropped when conditions deteriorate. The VP2, by virtue of less optimal frequency correction, has a fuzzier signal? I guess my question is why are the two devices correcting the frequency differently?

Does the CC1021 chip handle frequency correction or would that functionality be handled by a different chip and/or software?
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Offline rdsman

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #46 on: January 18, 2018, 12:56:12 PM »
So the objective here is to somehow prove/disprove that the VP2 does in fact track both transmitters independently.......

There can sometimes be a difference between the two channels' correction factors on the VP2 console. Usually it differs only by 1 but sometimes 2. So if the ISS is 1, the wind will be 2 or 3. Thus it would appear it is tracking them independently. Now, if you mean independently (a.k.a. differently) from the Vue, then yes, that, too, is true and might be a cause for concern.

It appears, if I understand this correctly, the Vue may do a better job finding the precise frequency of each transmitter which creates a better signal lock more resistant to being dropped when conditions deteriorate. The VP2, by virtue of less optimal frequency correction, has a fuzzier signal? I guess my question is why are the two devices correcting the frequency differently?

Does the CC1021 chip handle frequency correction or would that functionality be handled by a different chip and/or software?

So it does appear that the VP2 is tracking both transmitters.  The frequency error compensation is done totally different for the two. 

For the CC1021:

http://www.ti.com/lit/an/swra063/swra063.pdf

So for the CC1021, a new frequency must be calculated and written to the FREQ_A register by the
processor every time the AFC register value changes.

For the CC1101:

http://application-notes.digchip.com/001/1-2121.pdf

The CC1101 on the other hand supplies the frequency error direct (FREQEST) and the accumulated value is simply written to the FSCTRL0 register by the processor. 


The frequency error is the total amount required to keep the receiver on track with the transmitter.  It doesn't matter which one (or both) drifted.  There is no reason to compare the comp values from the Vue to the values the VP2 is using.  They have nothing to do with each other.

Maybe the CC1101 can track farther? (Resolution is FXTAL/2^14 (1.59kHz-1.65kHz); range is 202 kHz to 210 kHz, dependent of XTAL frequency.)  Not readily spelled out for the CC1021....



« Last Edit: January 18, 2018, 01:14:32 PM by rdsman »
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Offline mcrossley

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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #47 on: January 18, 2018, 01:00:26 PM »
One thought, temperature could affect more than just transmitter frequency, like the CPU clock frequency. If that drifts then the transmissions may fall outside the consoles reception window - I know as I had to add a correction factor to my Arduio transmission timing to prevent sync loss on the VP2 console.

I haven't read all the other threads, so apologies if this has been dismissed before.
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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #48 on: January 18, 2018, 01:05:22 PM »
One thought, temperature could affect more than just transmitter frequency, like the CPU clock frequency. If that drifts then the transmissions may fall outside the consoles reception window - I know as I had to add a correction factor to my Arduio transmission timing to prevent sync loss on the VP2 console.

Mark, yes, that was exactly my thought, as I tried to explain upthread. I'm no wireless engineer but seems to me that there are various parameters that could be affected by some clock or other reference frequency drifting off and then affecting timings of some other key parameter. I don't know how sensitive the channel time windows are, for instance.
« Last Edit: January 18, 2018, 01:10:54 PM by johnd »
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Re: Davis still using the CC1021 in current VP2 and/or VUE hardware?
« Reply #49 on: January 18, 2018, 01:08:28 PM »
OK, good to know rdsman. It would appear there is no direct evidence currently that this is a frequency issue.

As for timing (mccrossley and johnd), perhaps the Vue receiver has a more liberal window for receiving packets?
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