Tagged: fsk

Update to the RTL-SDR Transmitting at 1270 MHz

In our previous post we featured a video by OH2FTG which showed an RTL-SDR transmitting at 1270 MHz. Now OH2FTG has written in to give us some more information about the RTL-SDR transmitter. He has done a short writeup explaining how it’s done on his website. It turns out that the RTL-SDR is actually capable of transmitting a FSK morse beacon using it’s leaky oscillator.

In the video, code written by another ham OH2EAT is used. OH2EAT’s code essentially changes the frequency on the transmitting RTL-SDR at up to 300 times a second using a modified driver. This is used to create a Frequency Shift Keyed (FSK) transmission.

The modulating transmitter code is not yet available as it is not yet ready for release. In the future OH2FTG hopes to build an amplifier to boost the signal output for further experiments.

Decoding Efergy Energy Monitor Signals with RTL-SDR

An Efergy energy monitor is a wireless device with an LCD screen that shows how much power your household is using. The device is useful for helping reduce power usage by determining what appliances cause the largest power draw.

Nathaniel Elijah has posted on his blog about how he was able to create an RTL-SDR based decoder for the FSK data transmissions sent out by the Efergy energy monitor. His program receives and decodes the transmissions, saving the data to an excel file for later analysis.

Gough Lui from the Goughs Techzone blog has also attempted decoding these energy monitors as well, and has written a large writeup on his experiences.

Update: Gough Lui has been working on extending Nathaniels software and now has it working in Windows, and sending broadcast UDP packets of the received data.

Decoding an Efergy Energy Meter with RTL-SDR
Decoding an Efergy Energy Meter with RTL-SDR and a Raspberry Pi