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tracker.json defaults should be more LoRa byte saving #56
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A first, partial stop gap solution for issue lora-aprs#56. Unfortunately, JSON does not provide syntax for comments.
as already written in the PR: the current configuration is just an example to show what the firmware is capable of. please see it as an example configuration and not a "must follow". every ham is responsible for his own data and should minimize airtime as much as possible. |
An empty
"path": ""
instead of"path": "WIDE1-1"
intracker.json
works perfectly fine if you are only interested in putting your beacon on the map. This saves 7 LoRa Bytes, which increases the chances of an error-free reception of the full packet.Local
WIDE1-1
digipeating from LoRa is anyhow very rare and not allowed in most countries without a digipeater license.The same gains hold true for an empty
"message": ""
intracker.json
. Currently we are wasting 12(!) Lora Bytes to"message": "LoRa Tracker"
. In the professional LoRa world, this is considered borderline criminal…Actually, there should be no option at all for a
"message"
in a LoRa tracker, and if still, then an occasional (e.g. 1 in 10) APRS Status Report (p.80) stands better chances of being received correctly. APRS-IS takes care of this information in a transparent manner.Furthermore, sending altitude data should be made optional and
false
by default. This saves a whopping 9 LoRa Bytes on air, since its format is/A=001234
. GPS reported altitude is anyhow prone to errors and for objects on the ground, the altitude can be inferred from a geographical map.Finally, on the tracker firmware level, the Destination Address could be simplified to a mere
AP
instead ofAPLT00
. That is another 4 LoRa Bytes saved, or 6 bytes if you let the iGate fill in this information. Limit the marketing of the firmware to the iGate."enhance_precision": true
adds another 5 Bytes, and because of the addition of a space actually 6 Bytes.In total, there is an immediate potential to save 7 + 12 + 9 + 6 + 6 = 40 Bytes on air, of which 25 Bytes without any firmware change; only through more sane
tracker.json
file defaults.Mic-E APRS compression (pp. 42-56) could shave off still more Bytes…
LESS IS MORE with LoRa,
because LoRa employs forward error correction (FEC) coding on a physical hardware level.
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