One common option to supply the small TTGO LoRa boards is to use a small power bank. For supply small devices like these boards I use one really cheap power bank, so cheap it can be obtained for 0.80 euros from China (with no 18650 li-ion cell included, of course).
The 0.80 euros power bank
It seemed to work just fine but powering a 433 MHz TTGO board I noticed the power bank itself radiates a lot of noise in this frequencies. UHF noise from a switching mode power supply is a new record for me!
But... Can it be cleaned?