Measuring Power Line Noise in the Neighbourhood with the RTL-SDR “Driveby” System

Over the last few months Tim Havens has been developing a portable RTL-SDR based scanner that he intends to use for geo-tagged noise floor readings. He hopes to use such a system to map sources of RF noise related to power lines so that he can contact his power company to resolve them.

Tim’s system uses a powerful Odroid XU3 which is a Linux based mini embedded computer that sells for $179 USD. The Odroid XU3 has dual quad core ARM CPUs which is enough power to run rtl_power with 5 RTL-SDR dongles simultaneously. Rtl_power is an RTL-SDR tool which allows you to scan and record the power levels in the frequency spectrum. By using 5 dongles he is able to scan the 49 MHz, 50 MHz, 144 MHz, 222 MHz and 432 MHz bands simultaneously.

From a previous post Tim writes:

The idea behind this project is to be able to MAP real-world Geo-tagged noise floor readings.  This can be used for the primary purpose I intended for this application (mapping of problematic sources of RF Noise related to power lines in the area so that I can approach the local power company to resolve them) or any other sort of RF signal MAPPING.  Such as cellphone/cellsite coverage or FM broadcast coverage (and dead spots) among other things.

RTL dongles are CHEAP, and reliable, although not 100% stable (they drift a bit for the first 5 minutes of warm up) they can be used to measure changes in the RF Noise Floor (once warmed up).  While they don’t really seem to be able to be calibrated to anything less than -87db all we’re really looking for are relative changes to the noise floor while driving around a particular location (there is probably some complex math that could applied to these measurements that could be calibrated).  So for this project these inexpensive receivers are really just fine.

While rtl_power is scanning, the Odroid uses a GPS receiver to tag the timestamped noise readings with GPS coordinates. Then by driving around with the system and combining the GPS coordinates with the noise floor readings from rtl_power he is able to create a heatmap showing exactly where in his neighbourhood noise levels peak, indicating a power line RF noise problem to be fixed by the power company.

Some more information about the hardware build of his system can be found on a previous post.

Powerline Noise Mapped with RTL-SDRs and GPS
Powerline Noise Heat Mapped with RTL-SDRs and GPS Logging
The Insides of the Driveby System
The insides of the driveby system

Tim also has uploaded a video to YouTube showing his system running a stationary test demonstrating the hardware and some of his custom software before everything was boxed up.

Driveby App stationary test

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Jeff Kelly

Wondering if there is simple way to take a band noise sample every hour so I can document the noise level on a band over a month or more? In other words the noise level for 144MHZ is S9 (or the db equiv). Over time I will be able to get some understanding about the band noise.
I think rtf_power should be perfect for this.

Any suggestions?


Tim R. Havens

Hey thanks for noticing my blog on this stuff. I was beginning to think I was posting to the world wide ‘either’ LOL.

This has been a fun project. I tend of over build stuff for the joy of it. There are probably thousands of ways to do this better. I just used what I already had on hand from previous projects for the most part.

This is still a project in-flux… I was finally able to get things on the road yesterday and here are the first results of the Driveby System mentioned in this article.

Thanks again for noticing rtl-sdr guys!

I’m always open to new ideas as well so please anyone interested contact me! I’d love to hear from you.


Two Airspy units can do a better job and should cost less.

Pat Barthelow

Very useful system. Congratulations! All could benefit also by supplementing this system, or kind of system with the Bible here, from the Navy Postgraduate School, Free download