I have complained for a long time that my data doesn’t backfill when Sense comes back online (even if it was not connected to Sense’s servers for just 30 minutes).
The first thing I did was to ensure that my Sense stayed on my WiFi network during these periods. For this, I setup a cron job that ARPinged the Sense unit once every minute, and logged the data. I could not use ping because the Sense unit does not respond to icmp-echo-request packets. Nonetheless, ARPing indicated no apparent connectivity issues at my end.
The next thing I did was to log the SNR for Sense by recording the general background dBm and the RSSI for the Sense unit over 24 hours. This script ran every 5 minutes. The average background was -87 dBm, and the average RSSI at the Sense unit was -68 dBm. So the average SNR is 19 dB, which I thought wasn’t bad.
But, a very helpful fellow-Sense user, Dave Sherrington (@dave_n_s), suggested I look into a poor WiFi signal as a possible issue. So, I did that last night. The closest AP to the Sense unit, which is in my garage, is several walls away. I wasn’t inclined to add an AP to the garage until I had some indication signal strength was an issue, so I replaced the antenna on the Sense with a 9 dBi directional antenna, and aimed it toward the AP that’s in my exercise/cat room. Over the last 20 hours, the SNR for Sense has ranged between 22-30, with an average of 24 dB.
While I was setting up the new antenna, Sense wasn’t transmitting data to the servers for about 35 minutes, which showed up as a gap in the data. But, I was pleasantly surprised that the data backfilled just fine - so the gap disappeared. I did a second test early this morning where I disconnected my cable modem for 30 minutes. That data backfilled also.
So @dave_n_s - thank you very much!!
And everyone else - measure the SNR for your Sense. 19-20 dB is sufficient for general internet browsing and pulling email, but clearly the volume of data sent by Sense needs a higher SNR - my experience indicates at least 23-24 dB. Also, while that difference seems small - it’s a log scale.
