# 868Mhz -138 km! it is possible!

**URL:** <https://www.thethingsnetwork.org/forum/t/868mhz-138-km-it-is-possible/37250>\
**Category:** Uncategorized\
**Created:** [May 22, 2020, 8:28am UTC](https://www.thethingsnetwork.org/forum/t/868mhz-138-km-it-is-possible/37250 "2020-05-22T08:28:48Z")\
**Posts on this page:** 1\
**Showing post:** 34

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**Author:** ![arjanvanb](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/arjanvanb/32/46626_2.png) [@arjanvanb](https://www.thethingsnetwork.org/forum/u/arjanvanb)\
**Post date:** [August 16, 2020, 3:46pm UTC](https://www.thethingsnetwork.org/forum/t/868mhz-138-km-it-is-possible/37250/34 "2020-08-16T15:46:33Z")

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> [@LoRaTracker](#):
>
> the air time for a 28,29 and 30 byte packet is the same

Ah, @cslorabox explained:

> [@Battery efficient LoRa revolution counter](https://www.thethingsnetwork.org/forum/t/battery-efficient-lora-revolution-counter/39135/13):
>
> there is granularity imposed by the 4/5 coding - the actual airtime doesn’t increase with each byte, but rather jumps each time a new coding group must be added, so you “pay” in airtime for the number of coding groups sent, even if the last one is only partially filled

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