Topic: Temperature errors due to packet loss?

[miraculon]

I was hoping that some of you Davis packet experts could provide some insight.

After running for months with 90%+ good packets per the VUE diagnostic screen, good packets have been in the 45%-63% range very recently. My VUE console that shows the local marina VP2 data via a long range repeater is sometimes showing a temperature discrepancy vs. what is reported via Weatherlink.com. (I recently fixed the WLIP upload issue over there). I see the exact same temperatures via the repeater on all my consoles, Envoys, and meteohub/bridge devices.

Normally the temperature has agreed quite well as I recall, especially during high packet rate success.

I know that during poor packet reception that I miss wind gusts, but this makes sense because the samples are being missed. For temperature, this is usually fairly static and I would not expect to see errors. The temperature has disagreed by as much as 2°F recently.

I took a VUE console over to the marina parking lot and configured it for Station #1 and watched the data from weatherlink.com and this console. They matched exactly.

What could the long-distance repeater be doing to introduce a temperature error? I have never seen this behavior before. (although I wouldn't have known from last October to this past week due to the loss of WLIP function)

I suspected and have observed signals in the adjacent 800MHz band (cell and emergency services) on my RF Explorer spectrum analyzer. I do have a BPF with the 902-928 MHz pass-band at the pre-amp feeding the repeater input.

Weatherlink: https://www.weatherlink.com/embeddablePage/show/372a56e9f20d41bab0877649cb397b2b/slim
Via repeater: http://rogerscityweather.com/marinavue/marina.html

Although this morning, it seems to be closer. Good packets are 63%. It was worst with good packets at around 45%.

Greg H.

[PaulMy]

Hi Greg,
The difference between the 2 is quite significant.  At 09:30 a.m. on the WL.com (looks like 1 min interval) it was 26.9°F and 49% compared to 29.3°F and 42% on the repeater link which looks like a 5 min interval. Wind also off quite a bit.
Again at the 09:35 and 9:40 time the temp and hum on the WL.com follows the previous update times- 26.9 and 26.8°D and 49% and 50%, and the same for the repeater 29.7 and 29.5°F and 43% and 44% so neither is fluctuating much.

I can't help on reception issues or packet losses, but could there be another Davis reporting through the repeater?

Enjoy,
Paul

[miraculon]

could there be another Davis reporting through the repeater?

I don't think so. When I reconfigured the VUE console for Station #1 (no repeater), and drove home from the Marina, it lost signal for good. (as expected)
If there was another #1 around, I would expect to see something from a another ISS.
Once home, I reconfigured this VUE to correspond with my own station transmitters.
I will re-try this again and see if a non-repeater signal exists.

The temperature is changing rapidly this morning, and this could be a sampling problem like wind gusts I suppose. Although Saturday, the temperature seemed to be fairly stable. Good packets are at 63% this morning still. There is some junk on the 800MHz band according to the RF Explorer, although I don't hear activity on the 800MHz trunking scanner.

Just as a side note, the local temperatures from my own transmitters is fairly close to the Marina VUE via repeater. Hmmm...  I have deliberately avoided using Sta #1 on any of my own stations.

Greg H.

[miraculon]

The "good packet" rate has improved to 63%.

The temperatures are agreeing fairly well this morning.

I wonder if the recent CME event was causing some RF disruption with the repeater signal. I had a lot of issues involving Smarthings, noise on VHF, poor WiFi, etc. the last few days that seem to have cleared up.

Maybe the temperature rate of change was causing a missed sample situation similar to what I see with wind. That is the only explanation that makes sense to me. I would think that data corruption would result in wild results affecting all parameters, which I did not see.

Greg H.

[johnd]

Only quick comment I'd make is to be careful about assuming that eg 63% reception equates to 63% within say every 10-min period. Reception could be dropping out completely for 30-60 mins at a time and then recovering to 90% for a couple of hours. It's important to look at the graph of wind reception vs time to get a feel for the pattern of reception.