Heltec WiFi LoRa 32 V4

ESP32-S3 board with an SX1262 and a power-amplifier front end rated 28 dBm. Needs its TX power set with a UK antenna in mind to stay under 500 mW e.r.p.

Specifications
Maker	Heltec Automation
MCU	ESP32-S3R2 (2 MB PSRAM); a V4-R8 variant uses ESP32-S3R8 (8 MB PSRAM)
LoRa radio	SX1262 with a PA/FEM front end
Max TX power	28 +/-1 dBm (high-power version); a 22 dBm low-power variant is also listed
Connectivity	Wi-Fi 2.4 GHz, Bluetooth LE
Flash	16 MB
Screen	0.96 inch OLED (optional)
GPS	None onboard; 8-pin SH1.25 GNSS connector
Battery	1.25x2 lithium connector, 3.3-4.4 V; solar input 1.25x2, 4.7-6 V
Deep sleep current	Under 20 uA (Heltec claim)
Vendor price (USD)	$17.90-$27.50 on heltec.org depending on configuration and warehouse (read 2026-10-29); no UK price verified

What it is

The Heltec WiFi LoRa 32 V4 is the follow-on to the V3. It keeps the SX1262 radio and ESP32-S3 but adds a power-amplifier front end, 16 MB of flash, a solar input and an 8-pin GNSS connector for an external GPS module. There is no GPS onboard. The OLED is optional.

Heltec's high-power version is rated 28 +/-1 dBm. A 22 dBm low-power variant is also listed. Meshtastic's firmware comments for the board describe the front end as giving about +7 dB at 21 dBm drive, with the amplifier compressing near its maximum.

Revisions. Heltec's wiki says V4.2 uses a GC1109 PA/FEM and V4.3 uses a KCT8103L FEM, and Heltec's product page is titled "WiFi LoRa 32(V4.3)" and says the board "now comes with the latest ESP32-S3R8 version", so check which variant you are buying and match your firmware to your board variant. If you build firmware yourself, select the matching FEM option. There is also a V4-R8 variant with an ESP32-S3R8, a different pinout and different firmware, which is not interchangeable with the standard V4.

Who it suits

Best for: someone who wants a V3 with a solar input and a stronger transmitter, and who will set TX power on purpose.

Not for: anyone who fits a gain antenna and leaves TX power at its maximum; that breaches 500 mW e.r.p. in the UK. Meshtastic's default TX power setting (0) means "region maximum", which is 27 dBm in EU_868. Set an explicit value no higher than 29.1 minus antenna gain (dBi); treat cable loss as zero unless you have measured it. Also not ideal for battery-only repeaters, where an nRF52 board draws less.

UK 868 MHz notes

Heltec sells the V4 in 863-870 MHz and 902-928 MHz versions. Choose the 863-870 MHz (868) version. We did not capture Heltec's exact SKU wording, so check the listing. See Buy the right frequency.

The arithmetic (ours): e.r.p. = TX power in dBm + antenna gain in dBi - 2.15 - cable loss. Cable loss is taken as 0 below.

Conducted TX	Antenna	e.r.p.	25 mW sub-bands	500 mW slot (869.40-869.65 MHz)
28 dBm	0 dBi	25.85 dBm = 385 mW	Over	Within
28 dBm	2 dBi	27.85 dBm = 610 mW	Over	Over
27 dBm	2 dBi	26.85 dBm = 484 mW	Over	Within
27 dBm	3 dBi	27.85 dBm = 610 mW	Over	Over

To stay within 500 mW e.r.p. the conducted power must be no more than about 29.1 dBm minus the antenna gain in dBi (less any cable loss allowance). With a 2 dBi antenna that is about 27.1 dBm.

Ofcom IR 2030 v1.16 (published 7 April 2026) is the source for the limits.

Firmware

Meshtastic: supported. Use the V4 firmware (firmware-heltec-v4-*); V4-R8 needs its own build.
MeshCore: supported. heltec_v4 and heltec_v4_r8 are in the MeshCore repository, and "Heltec v4" is in the flasher catalog.
RNode / Reticulum: listed. The Reticulum manual names the Heltec LoRa32 v4.0, but RNode_Firmware has a single model for it described as 850-950 MHz, 28 dBm, with no separate 868 MHz model. We have not confirmed that the 863-870 MHz hardware tunes correctly under RNode, so test before you rely on it.

Flashing: Flash Meshtastic, Flash MeshCore, RNode and Reticulum setup.

Known quirks

V4 and V4-R8 firmware are not compatible. Pick the one that matches your board.
Select the right FEM option for V4.2 versus V4.3 when building firmware yourself.
The V4 dropped the CP2102 USB-serial chip and uses native USB, so the driver advice for the V3 does not apply.
Attach the antenna before power.

Power

Heltec claims a deep-sleep current under 20 uA. We found no credible receive or idle measurement for the V4, so no reliable figure is published here. A third-party MeshCore low-power firmware repository says "other boards save a similar 2-3 mA" off their idle figure, which refers to boards generally rather than the V4. It does give two V4 figures: "a Heltec V4 repeater idles at about 13.5 mA with the bridge running" (the repeater's ESP-NOW bridge), and "~23 mA mean current measured on Heltec V4.3 Companion" with its GPS module in duty-cycle mode. These are the repository's own statements, not audited, and neither is a receive-only figure. Measure your own node. See Power.

Guides: Flash Meshtastic, Flash MeshCore, RNode and Reticulum setup, Power, Antenna placement
Tools: Link budget calculator, Solar node sizing
Other boards: Heltec WiFi LoRa 32 V3, Heltec Wireless Tracker, Seeed XIAO ESP32S3 + Wio-SX1262
Comparison: Meshtastic vs MeshCore