# TTGO T-Beam topic

**URL:** <https://www.thethingsnetwork.org/forum/t/ttgo-t-beam-topic/15297>\
**Category:** End Devices (Nodes)\
**Created:** [June 25, 2018, 2:58pm UTC](https://www.thethingsnetwork.org/forum/t/ttgo-t-beam-topic/15297 "2018-06-25T14:58:18Z")\
**Posts on this page:** 1\
**Showing post:** 83

<div class="post-metadata">

**Author:** ![rem73](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/rem73/32/35697_2.png) [@rem73](https://www.thethingsnetwork.org/forum/u/rem73)\
**Post date:** [January 31, 2019, 9:42pm UTC](https://www.thethingsnetwork.org/forum/t/ttgo-t-beam-topic/15297/83 "2019-01-31T21:42:14Z")

</div>

Hello,  
After many investigations i have the solution to improve the poor level of transmit power on Lora TTGO version 1 at 868 Mhz ( I suppose it is version 1.) The lora TTGo like this :

> **[US $12.16 15% OFF|TTGO 868MHz/915MHz SX1276 ESP32 LoRa 0.96 Inch Blue OLED...](https://www.aliexpress.com/item/TTGO-868MHz-915MHz-SX1276-ESP32-LoRa-0-96-Inch-Blue-OLED-Display-Bluetooth-WIFI-Lora-Kit/32840258107.html)**
>
> Smarter Shopping, Better Living! Aliexpress.com

There are 2 issues :  
Software :LMIC library is not clear on this side : Check radio.c file, and go to SX1276 power definition ( about line 476 ) : add this at the end of configuration file: writeReg(RegPaConfig,0b01111111) : It suppose you have a hardware witout Paboost connected.

Hardware:Is low cost, interresting but poor RF design. I remove all the parts at he RF filter. I apply the Semtech ref design to changes 8 capacitors and inductors, and use Pa output without Paboost option  
[https://www.semtech.com/uploads/documents/SX1276MB1MAS\_e315v01a\_prod\_folder.zip](https://www.semtech.com/uploads/documents/SX1276MB1MAS_e315v01a_prod_folder.zip)

Measurement are performed with radio laboratory equipement in conducted condition : about ±0,1 dBm absolute accuracy. That’s my job.

Before : 2dBm : about 1,6 mW ( with LMIC modification describe above)  
After : 14dBm : 25mW. ( with LMIC same modification describe above)

Conclusion : some issue around lora TTGO could be the result of wrong parts…Simply apply Semtech refdesign could solve the issue, without hard optimisation, without network analyser and PCB effect compensation.

I don’t check the receiver parts. May be some errors on design again…

You cannot have this kind of issues with RFM95 module.

---

_[View the full topic](https://www.thethingsnetwork.org/forum/t/ttgo-t-beam-topic/15297)._