Optional transmitters & station setting on VP2

[Touchtone]

I am wondering what station numbers people are using for optional wireless transmitters, such as the 6332 Anemometer Transmitter. Normally station 1 is used for the ISS. I was using station 2 for the 6332 but I noticed when checking signal strength there was occasionally a dashed out reading occurring, which I thought may be caused by both the ISS & 6332 signals arriving at exactly the same instant. Someone suggested that it is better to separate the stations by a greater number so I set the 6332 to station 5. While that seems to work better it does take a lot longer to find the wind speed if you have to reset the clock or do some other resetting on the console.

I assume that when the console is searching for transmitters it starts at 1 & then progresses through till it find the next & so on. So having them closer together should speed up that process.

[moe3]

On my VP2, I use #1 for the ISS, #2 for a T/H station, #3 for another T/H, #4 for a 6332(used as a Temp. station) and #5 for a Leaf/Soil station. I also have a Vue console that listens to a seperate VP2 ISS (6322) that I run as Station #6. Between 2 different systems, my reception rate is better than 90 % across the board. The higher station ID #'s do increase the time from about 2.5 seconds(#1) to almost 3 seconds(#8). Sometimes, it takes my VP2 console up to 8 or 9 minutes to hear all 5 stations before I can be 'Done'. Hope this helps you.

[Touchtone]

Thanks for that. I was just wondering what seems to be the general consensus on station setting with only one extra transmitter apart from the ISS.

I use both Cumulus & WeatherLink for my weather data as I don't run my computer 24/7. I noticed that when I first set up my station, March 2013, that if I checked the database in WL right over on the RH Side there is a column that says Wind Tx which is the station number for the wind transmitter, in my case this started off showing Wind Tx 2 & then for some reason it stated to show this as Tx !. This caused as drop in the ISS reception figure from it's usual 99.2-100% figure down to 96 or 97%. Normally if you only have the ISS reporting wind & all the other standard sensors then Tx 1 would be the correct reporting.

I also think this was the cause of the occasional dash on the signal strength number when checking that. Since changing the 6332 transmitter to station 5 WL now reports this as Tx 5 & the ISS reception is 99.2-100% again. Perhaps the transmitting frequencies are too close together & the station can't separate them properly, so is reporting incorrectly.

[prodata]

The general advice is to always use the lower channel numbers first, with the anemometer channel as #1. It should make no difference to performance if you use adjacent channel numbers for two or more transmitters.

NB The different channels are not on different frequencies (although there is of course the overlay of the frequency-hopping protocol affecting exactly which frequency a given packet may be broadcast on), rather the channels are separated in the time domain. It's the delay after a reference time point (reset from time to time by the synchronisation process) which distinguishes the different channels.

[Touchtone]

The general advice is to always use the lower channel numbers first, with the anemometer channel as #1. It should make no difference to performance if you use adjacent channel numbers for two or more transmitters.

NB The different channels are not on different frequencies (although there is of course the overlay of the frequency-hopping protocol affecting exactly which frequency a given packet may be broadcast on), rather the channels are separated in the time domain. It's the delay after a reference time point (reset from time to time by the synchronisation process) which distinguishes the different channels.

Thanks John for that. Are you recommending that channel 1 should be used for the anemometer & the ISS set to channel 2 as an example, when the anemometer has it's own separate transmitter & not running through the ISS.

[prodata]

Are you recommending that channel 1 should be used for the anemometer & the ISS set to channel 2 as an example, when the anemometer has it's own separate transmitter & not running through the ISS.

Yes, in a word! But I really don't think it makes a huge difference when we're talking about channels #1 and #2 for the VP2 - the suggestion is more about avoiding the high channel numbers for the anemometer channel. AIUI there was more of a channel dependency with the VP1 wireless protocol and it's less of an issue with VP2, but still if you're looking for a principle as to which channel numbers to use then stick to the low numbers for that last 0.1% of reception and responsiveness for the anemometer.

[Touchtone]

Are you recommending that channel 1 should be used for the anemometer & the ISS set to channel 2 as an example, when the anemometer has it's own separate transmitter & not running through the ISS.

Yes, in a word! But I really don't think it makes a huge difference when we're talking about channels #1 and #2 for the VP2 - the suggestion is more about avoiding the high channel numbers for the anemometer channel. AIUI there was more of a channel dependency with the VP1 wireless protocol and it's less of an issue with VP2, but still if you're looking for a principle as to which channel numbers to use then stick to the low numbers for that last 0.1% of reception and responsiveness for the anemometer.

Thanks very much John. Actually I have given your recommendation a lot of thought & checked the timing of the stations from the manual & I can see what you mean.
From what I can workout when channel 1 is selected with the DIP switches in the transmitter is should transmit every 2.25 seconds. Channel 2 should transmit every 2.357 seconds approx. & each channel number increasing transmission time by 0.107 seconds approx. to a maximum of 3 seconds for channel 8.
I will change my transmitter DIP switches & reset the console accordingly, with the anemometer on channel 1 & the ISS on channel 2.

[prodata]

On a VP2 (VP1 was different) channel #1 transmits every 2.5625 secs. Subsequent channels are then offset in time as you describe. (I suspect you remember the 2.25secs you've mentioned from the gating interval for the anemometer on the WMII and which I think was also carried across to the VP1/VP2 stations. So, once you start to really dig into the detail of things, you realise that slightly different timings apply in different places. The average timing of the loop packets that Cumulus picks up is something else again.)

[RayProudfoot]

I'm a bit late joining this discussion but I have a wireless VP2 and an additional transmitter for the anemometer. The ISS is channel #1 and the anemometer #2.

My station has been operational since May 2009 and pretty much trouble-free even using the original batteries for both transmitters.

The station does go through phases where the number of resyncs does sometimes increase for no obvious reason but data capture looks to be fine.

The percentage of good packets received is around 98% +/- 0.2%.

[Touchtone]

Thanks very much for all the info John. I didn't get the timing information from my memory of the WMII as I have only just become a Davis user, I got it from the specs info towards the back of the console manual as it mentions the timing of 2.25 to 3 seconds with ID 1 being the shortest & ID 8 being the longest. My previous station was an Oregon Scientific WMR 928 NX, which was 5 years old when it gave up.

I have reset the channel ID's so No 1 is now the anemometer & channel 2 is the ISS. This does seem to have "tweaked" the system & wind speed & direction do seem far more responsive on the console.
One thing I learned was that the station number shown on the console in normal running mode is now station 2, whereas before it was station 1. So apparently the actual station No is set by the ISS, depending on what channel ID it is set on.
The percentage of good packets received is always over 99% & the signal strength ranges from 44 to 60. I have 2 consoles so the distance between the outside transmitters & each console is different to explain the signal strength variation, so in more detail, console 1 reports 59-60 for the ISS & 44-59 for the anemometer & console 2 reports 59 with an occasional 60 for both transmitters.
Changing the Channel ID's has not altered the above wireless reception figures.
Best regards
Bligh.

[prodata]

I didn't get the timing information from my memory of the WMII as I have only just become a Davis user, I got it from the specs info towards the back of the console manual as it mentions the timing of 2.25 to 3 seconds with ID 1 being the shortest & ID 8 being the longest.

Interesting - must admit that I've not noticed that 2.25secs detail in the console manual before. But I suspect that it's a typo.

If you look in the Serial Tech Ref documentation (III 3) you'll see the timing of the packets described in a little more detail and confirming the 2.5625 secs figure on #1. This SRT document should be the one that's been gone through in most detail from a technical point of view and so I'd regard this as the most credible source.)

Similarly, the Appendix in the ISS manual implies 2.5625secs (actually it says 2.5-3 secs - but my guess is that figure has been copied from from the VP1 details, which was 1/16 sec shorter)

This is all fine detail of course and irrelevant for most practical purposes. But it would have been nice to see the Davis documentation more internally consistent.

[Touchtone]

I didn't get the timing information from my memory of the WMII as I have only just become a Davis user, I got it from the specs info towards the back of the console manual as it mentions the timing of 2.25 to 3 seconds with ID 1 being the shortest & ID 8 being the longest.

Interesting - must admit that I've not noticed that 2.25secs detail in the console manual before. But I suspect that it's a typo.

If you look in the Serial Tech Ref documentation (III 3) you'll see the timing of the packets described in a little more detail and confirming the 2.5625 secs figure on #1. This SRT document should be the one that's been gone through in most detail from a technical point of view and so I'd regard this as the most credible source.)

Similarly, the Appendix in the ISS manual implies 2.5625secs (actually it says 2.5-3 secs - but my guess is that figure has been copied from from the VP1 details, which was 1/16 sec shorter)

This is all fine detail of course and irrelevant for most practical purposes. But it would have been nice to see the Davis documentation more internally consistent.

Thanks John. Where could I find the STR (III 3) documentation that you refer to?. I would just be interested in reading it.
For your information the timing I referred to in on page 48 under Console Data Display Specifications & listed as Transmission Interval. My console manual is Rev K 12 Jan 2012
Thanks again for your help & the information you have supplied. It's nice to be in contact with someone that knows a lot about Davis.
Regards. Bligh.

[prodata]

http://www.davisnet.com/support/weather ... s_v261.pdf

[Touchtone]

Thanks John. I have copied that document & I will read it through later, when I have plenty of time.
Regards. Bligh.

[prodata]

Thanks John. I have copied that document & I will read it through later, when I have plenty of time.
Regards. Bligh.

Well, it's not really easy reading (unless you're having trouble sleeping that is) - just browse through it is the best suggestion. But the first main section will give you some idea of how the API works and includes the short paragraph on channel timing. Other than that it's obviously intended for users who want to write their own software. But you did ask!