ESP32 restarts while Transmitting LoRa signals

[dinislam_jsr]

I was running a device built with an ESP32, an LoRa Ebyte E32 433T30D module, a Neo 6M GPS module, and an SSD1306 0.96 inch OLED on a breadboard, and it was working beautifully.

However, when I try to run it on a veroboard using header pin connections, the ESP32 restarts during the LoRa module's transmission.

I've provided separate 5V power to the LoRa module and the ESP32 using separate power modules.

The external 5V power is connected to the 5V In pin of the ESP32. The Neo6M and OLED VCC are powered from the ESP32's 3.3V pin.

In this setup, the grounds of the LoRa Module, ESP32, GPS module, OLED, and the power module (LM2596) are all soldered together.

I've made the connections between pins using thick, insulated wire and tested for continuity after soldering. Everything seems fine.

When the ESP32 restarts during transmission, the following text appears in the Serial Monitor:"

Serial Monitor Reset Log
etsÀþþets Jul 29 2019 12:21:46
rst:0x1 (POWERON_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0030,len:4980
load:0x40078000,len:16612
load:0x40080400,len:3480
entry 0x400805b4
reset log

[davefes]

First thing I would check is the amount of current drawn out of the 3V3 regulator by the GPS module and OLED display. Is the ESP32 on a dev board? You really need an oscilloscope to watch for voltage "dips" while things boot-up.

What happens if you leave the GPS module disconnected during boot-up?

[dinislam_jsr]

I've tried disconnecting GPS Module, got the same result.
Also tried without OLED and GPS Module, got the same result.

[davefes]

Just looked at the EBYTE datasheet. 1W output, maybe try reducing the TX power. Have you got a SMA 50 Ohm termination you can try on the antenna connector? Is the ESP32 on a dev board? Might need a schematic showing your connections.