Problem with ESP32 lora V4 range

[medusa]

Hello Heltec Support,

I’m using Heltec LoRa esp32 V4 boards on 915 MHz and I’m seeing extremely poor LoRa performance compared to LoRa esp32 V3. With the same antennas and the same LoRa PHY settings and code, the V4 range is unusably low.

To isolate it, I ran a minimal RadioLib TX/RX test (no mesh, no OLED, no WiFi/SPIFFS logic).

Test setup:
Frequency: 915.0 MHz
BW: 125 kHz, SF: 12, CR: 4/5, SyncWord: 0x12, Preamble: 8, CRC ON

Measured results (about 1 meter):
V3 to V3: RSSI ≈ -16 dBm, SNR ≈ +4.2 dB
V3 to V4: RSSI ≈ -71 dBm, SNR ≈ +4.0 dB
V4 to V4: RSSI ≈ -127.5 dBm, SNR ≈ -14 dB

The V4 to V4 result (-127 dBm at 1 meter) is basically near noise floor!
The LoRa antenna is connected to the LoRa IPEX connector, not the 2.4 GHz IPEX
The same 915 MHz antenna used on V3 is used on V4.

Does the V4 require any additional RF control or configuration?
Is there a known issue or revision difference in the V4 LoRa RF front-end that could cause severe attenuation?

[UniquePete]

When not using the Heltec LoRa software (the LoRaWan_APP software does this stuff ‘invisibly’), there are a few extra controls that have to be set—from a PM with @bns on this very subject:

It took a bit or ferreting around through the LoRaWan_APP code to find the relevant control details, but the essentials appear to be as follows:

#define LORA_PA_POWER  7
#define LORA_PA_EN     2
#define LORA_PA_TX_EN  46

pinMode(LORA_PA_POWER,OUTPUT);
digitalWrite(LORA_PA_POWER,HIGH);

pinMode(LORA_PA_EN,OUTPUT);
digitalWrite(LORA_PA_EN,HIGH);

pinMode(LORA_PA_TX_EN,OUTPUT);
digitalWrite(LORA_PA_TX_EN,HIGH);

[bns]

Oh, is THAT where I left that code

[medusa]

thanks , the boards are working now.