FAQ: transmission frequency

The frequency, inverse of the the interval, for the distributed firmware is different for each mode,

version	raw (highres) ms	URL ms
		coded	measured
2.2.2	1000
1.2.12	1000	500	508
1.0.1	1000	500

This seemingly very rapid transmission is an attempt to remediate the inherent poor percentage of sucessful packet reception of the BLE packets.

Here is a sample of packet reception times as seen by a raspberry pi zero Nothing was moving, the ruuvi and the pi were 4 meters apart, indoors. Notice the missing samples.

 >hcidump -t|grep --line-buffered  --before-context=3  --after-context=4 'bdaddr C7:10:3C:68:24:C2'|\
egrep --line-buffered '2018|RSSI'
2018-11-07 22:54:05.340086 > HCI Event: LE Meta Event (0x3e) plen 43
      RSSI: -65
2018-11-07 22:54:05.840114 > HCI Event: LE Meta Event (0x3e) plen 43
      RSSI: -84
2018-11-07 22:54:06.342644 > HCI Event: LE Meta Event (0x3e) plen 43
      RSSI: -85
2018-11-07 22:54:06.850133 > HCI Event: LE Meta Event (0x3e) plen 43
      RSSI: -85
2018-11-07 22:54:07.355129 > HCI Event: LE Meta Event (0x3e) plen 43
      RSSI: -79

2018-11-07 22:54:08.364490 > HCI Event: LE Meta Event (0x3e) plen 43
      RSSI: -84
2018-11-07 22:54:08.866807 > HCI Event: LE Meta Event (0x3e) plen 43
      RSSI: -83
2018-11-07 22:54:09.376688 > HCI Event: LE Meta Event (0x3e) plen 43
      RSSI: -84
2018-11-07 22:54:09.880479 > HCI Event: LE Meta Event (0x3e) plen 43
      RSSI: -83

2018-11-07 22:54:10.385499 > HCI Event: LE Meta Event (0x3e) plen 43
      RSSI: -78
2018-11-07 22:54:10.884945 > HCI Event: LE Meta Event (0x3e) plen 43
      RSSI: -84
2018-11-07 22:54:11.891446 > HCI Event: LE Meta Event (0x3e) plen 43
      RSSI: -85

2018-11-07 22:54:12.393816 > HCI Event: LE Meta Event (0x3e) plen 43
      RSSI: -79
2018-11-07 22:54:12.900664 > HCI Event: LE Meta Event (0x3e) plen 43
      RSSI: -79
2018-11-07 22:54:13.402499 > HCI Event: LE Meta Event (0x3e) plen 43
      RSSI: -89

2018-11-07 22:54:15.421055 > HCI Event: LE Meta Event (0x3e) plen 43
      RSSI: -79

Reducing the frequency has some effect on the battery lifetime, especially in harsh environments.