With each read the system saves some useful information about the passing, understanding this can help to better interpret your data and identify potential problems.
Since Active Transponders contain more onboard circuitry and communicate on the 2.4GHz channel they are able to store and send more information with each passing, understanding the Hits / RSSI values is also slightly different as explained below.
- Hits - The number of times the transponder has seen the loop pattern (which is repeated at 150 times per second), up to the strongest Loop Strength.
- RSSI (only useful for V2 Transponders and beyond, not applicable to Basic Transponders) - There are two radio links involved, 125kHz Loop and 2.4GHz Antenna for data communcation. We want to know the quality for both, which is why the system reports two values packed into one figure.
- X refers to the 2.4Ghz received signal strength where -90dBm is the weakest and -58dBm is the strongest signal
- Y refers to the Loop power where 1db is the weakest and 16db is the strongest.
- Loop - The Loop ID of the device which recorded the passing.
- Channel - The Channel ID of the device which recorded the passing.
- WUC - Wake-Up-Count of the transponder is the number of times the transponder has been activated by a loop.
- Batt - The battery voltage of the transponder, we recommend retiring transponders with < 2.2v.
- Temp - The internal temperature of the transponder.
- SFlag - Will be between 64 and 127, or greater than 192, if the passing was stored on the transponder or the V3 Transponder issued a warning.
| Guidelines for detection strength | Hits | 2.4GHz RSSI (X) | 125kHz Loop (Y) |
| Perfect (could not be better) | 20..60 | better than -75dBm (-58dBm best for passing) |
8dB...16dB |
| OK (nothing to worry about) | 10...20 | -80dBm...-70dBm | 6dB...10dB |
| Not Great (still working, but could be better) | 5...10 | -85dBm...-75dBm | 4dB...8dB |
| Barely Detected (setup should be checked) | 1...5 | -90dBm...-80dBm | 1db...4dB |
How to improve detection quality:
- 2.4GHz: Make sure the receiving antenna has a direct line of sight to the transponder. If this is not the case, try replacing the receiving antenna (elevating it) and/or use our Range Extender.
- 125kHz: Make sure there is a direct line of sight between the loop and the transponder. When mounting the transponder on metal/carbon, please use our Chip Holders to leave some space between the transponder and metal. Also check the loop width, loop power (detection height) and transponder placement.
Calculation of RSSI Values
Active Box FW 2.4 and older: This value represents the maximum loop strength (Loop_Strength, see below) a transponder saw while recording the passing.
From FW V2.5 and newer: This value represents both, the maximum loop strength and the 2.4GHz strength the passing was received by the Active Box. The 8-Bit Value is bitwise devided XGGGLLLL (x must be ignored, G = 2.4GHz, L = Loop)
- 2.4GHz_Strength = -90 + 4 * GGG [dBm]
2.4GHz received signal strength at Box Antenna where -90dBm is the weakest and -58dBm is the strongest signal - Loop_Strength => 1 + LLLL
Loop Power in positive dB values from 1..16 where 1 is the weakest and 16 is the strongest
Examples:
16: 00010000 => 2.4GHz=-90+1*4 [dBm] and Loop=1+0 => -86dBm/1 77: 01001101 => 2.4GHz=-90+4*4 [dBm] and Loop=1+13 => -74dBm/14