RF is all around us ... starting your own station frequency survey

Foundations of Amateur Radio

As a self-proclaimed radio nerd I'm aware of the various amateur bands. Depending on your license, your familiarity will likely vary. I've never been on 6m for example, but I have a good working relationship with the 10m band.

Amateur bands aside, there's plenty of other activity across the radio spectrum. It occurred to me that I've never actually stopped to take note of what specifically I can hear from my own station. Think of it as a station frequency survey.

Obvious sources are AM and FM radio broadcasters. Then there's the aviation frequencies, the local control tower, arrival and departure frequencies as well as Perth airport ground on occasion. There's the ATIS, the Automatic Terminal Information Service. There was a time when I could hear various aviation non-directional beacons, or NDBs, that are near me, but many of them were switched off in 2016. I haven't yet found a current list of which of the 213 remaining navigation aids that form part of the Backup Navigation Network across Australia are still on the air.

As it happens, there's currently some horrendous noise on HF with several new potential sources that I have not yet identified, a pool pump, a bank of solar panels, plasma TV, you name it.

Staying with aviation, I've briefly played with Automatic Dependent Surveillance-Broadcast, better known as ADS-B, or ADSB, on 1090 MHz. If you have a PlutoSDR, I updated the dump1090 program to use Open Street Map several years ago. You can find it on my VK6FLAB GitHub page. If you want to see some very interesting visualisations for ADSB, have a look at the adsb.exposed website.

Further up the frequencies are things like 2.4 and 5 GHz Wi-Fi. In a previous life, before I was an amateur, I played with Ku-band satellite frequencies in the range between 12 to 18 GHz, specifically DVB-S, or Digital Video Broadcasting - Satellite.

While that's an impressive list of things, it leaves an awful lot of unexplored territory. For example, the local trains and public transit authority, the fire and emergency services, the volunteer bush fire brigades, water bombers and the like.

I've not even looked at local digital services like DVB-T, that's the terrestrial standard, or the local radio version, DAB+, or Digital Audio Broadcasting.

Then there's pagers, and countless marine services and channels, the ubiquitous CB frequencies and a couple of pirate ones, and global services like GPS, weather satellite and other Earth monitoring services.

Note that I'm specifically highlighting things that I can hear at my station, or more precisely, should be able to hear. I'm in the process of figuring out which particular tools I need to actually have a stab at hearing and decoding things like weather satellite.

I wouldn't be me if I didn't try this with my hands tied behind my back. I'm limiting myself to things I can hear using the antennas that I already have. I don't, well not at this stage, want to start building and installing more antennas, probably because in the not too distant future I plan to finally erect a replacement HF antenna, but that's a story for another day.

As for now, I'm plotting noise levels using a tool called rtl_power. I'm working on figuring out what extra noise has joined my environment. I'm also starting to make a concerted effort to document specifically what I've actually heard. Not so much a continuous log, more of a one-way log if you like, some might call it a shortwave listener log.

What RF sources have you heard in your shack and how many of them did you document?

I'm Onno VK6FLAB