An eclectic selection of technology with some cookery
I have a basic RTL-SDR dongle I had the idea to use as a poor mans spectrum analyser. Out of intrest I thought i’d try it out as an SDR radio first to see what I can pick up and as a quick memory refresh regards radio. Researching how to set this up I discovered there’s a great dearth of information about running SDR software on Apple Mac computers. I thought I’d put my notes together in the hope it my help someone else.
I used a RTL-SDR blog v3
One thing to note is for anything between 500kHz to 25MHz put the dongle (RTL-SDR) in to Direct sampling Q branch. Also don’t forget to put it back or you might find Short wave broadcasts appearing in 100MHz bands.
I got 3 Client working on my Mac
By far the best, relatively easy to use (as SDR goes) and so far very reliable. the only down side being its on Mac ports not Home Brew so needs sudo to install! I have a rather uneasy feeling every time I use Mac Ports. I have to say I do like the ability to scroll the spectrum if a signal is a few MHz away.
sudo port install SDRPlusPlus
Health warning! Any package manager that requires “sudo” can be very bad for your systems health!
Looks pretty comprehensive although both my Mac and dongle got very hot when using it.
brew install --cask cubicsdr
Simple and easy to use, possibly a good starting point but lacks the features of other tools.
brew install --cask sdrdx
Although a PC only tool I did give it a quick go on an old PC as it has lots of good reviews. Personally I struggled to get a good broadcast FM signal out of it where as SDR++ did a much better job on the same PC. As for the install process, lets just say I’m sticking to my Mac, argh drivers.
I use an old (mid 2000’s) indoor VHF TV / UHF TV / FM antenna, although not an obvious choice it seems to get good signals across a wide spectrum and I happened to have it to hand. I’ve had it working on the following bands with reasonable signal quality:
It has two 1m ish telescopic vertically antennas and a directional loop antenna. It has a built in amplifier with adjustable gain. I’ve since built some custom antennas which are better but it was a good starting place.
Fancy using your RTL-SDR to decode data from a 433.92 MHz sensor (Car tyres for example).
The RTL repository is here. This can be used to decode data from various devices and not just on 433MHz.
brew install rtl_433
For frequency allocations see the ITU Frequency Bands allocated to Terrestrial Broadcasting Services page
I’ve not been able to pick this up, I suspect this is down to my Antenna choice.
I found this still to be quite interesting although it seems in decline.
The SDR software dose a good job of receiving these signals with very good sound quality. Much better than DAB and some internet streams so still worth listening to.
SDR++ does not pick these up directly however you can install a dedicated piece of DAB software to decode the signals. I used welle.io.
sudo port install welle.io
Health warning! Any package manager that requires “sudo” can be very bad for your systems health!
Worked really well although it listed the configuration of each stream and made it clear why DAB can sound so terrible. 32kHz sample rate on 40kbit/s AAC or 80kbit/s Mpeg 1 layer II any one?
I’ve not explored this.
There are a few things of interest, mainly in the amateur band such as FT8 and down links from the International Space Station. Otherwise I’ve only found this of interest to test out equipment I own to confirm it’s operation.
For a list of amateur bands see the ITU Radio regulation site.
Not entirely sure I can take the frames site seriously. Most countries then have band allocation lists with more detail and some contries have additional bands such as the UKs 4m band.
There are also broadcasts from the International Space Station which may be of interest.
One thing that was of interest was listening in to the FT8 protocol and seeing how far away you can pick a signal up from. I managed to pick up stations pretty much the other side of the plant from me. You will need the following software.
brew install Soundflower
sudo port install SDRPlusPlus
brew install wsjtx
brew install gridtracker
UK channels CB channels only permit FM/PM only
I used to have 2-way radios that used this band but as I belive it’s mostly used for baby monitors now so I’ve not investigated. From memory you where lucky to get 10m with a reasonable signal.
Not sure I’ve ever head of anyone who owned the equipment let alone used it, Given the 10mW power it’s not surprising. I’ve included this out of curiosity.