SX1308 LoRa baseband + SX1255/7 chipset -142.5 dBm @ 300 bps Sensitivity Maximum transmit power is 27 dBm.
Antenna for LoRa

heltec indoor miner
1.5m (60″) table-top external antenna “) Ethernet cable
IEEE 802.11a/b/g/n/ac 10/100M Wi-Fi Double frequency 2.4 GHz/5 GHz with inbuilt antenna
Bluetooth V5.0 EDR and BLE with an inbuilt antenna
CPU Quad-core Cortex-A53 64-bit 1.5 GHz RAM 2 GB DDR4 ROM 32 GB eMMC 5.1 12V DC power, 500mA maximum, 160mA normal (2W). An external 120/220V AC adaptor is supplied. 5.5mm/2.1mm barrel connection
Package Case Dimensions: 120 mm x 115 mm x 35 mm ” (4.72″ x 4.53″ x 1.38″)
Dimensions: 120 mm x 122.5 mm x 40 mm (with feet, and including LoRa antenna connector)
Case made of 6063 aluminum alloy; top made of tempered glass
Female RP-SMA Antenna Connector (RP-SMA mating)