Earlier in the week a video comparing a Discone to a Coax Collinear antenna for ADS-B reception was posted. The author of that video has now posted on his blog a tutorial on how he made the coax collinear antenna. Check out the video tutorial below.
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***PLEASE NOTE THAT THIS TUTORIAL IS OUTDATED.***
Currently, we recommend using the SatDump software instead. A modern tutorial for SatDump can be found at https://www.a-centauri.com/articoli/noaa-poes-satellites-reception.
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Everyday multiple NOAA weather satellites pass above you. Each NOAA weather satellite broadcasts an Automatic Picture Transmission (APT) signal, which contains a live weather image of your area. The RTL-SDR dongle combined with a good antenna, SDRSharp and a decoding program can be used to download and display these live images several times a day.
This tutorial will show you how to set up a NOAA weather satellite receiving station, which will allow you to gather several live weather satellite images each day. Most parts of this tutorial are also applicable to other software radios, such as the Funcube dongle and HackRF and Airspy, but the RTL-SDR is the cheapest option. Hardware radio scanners can also work, provided the radio has a large IF bandwidth (30 kHz +) and a discriminator tap.
Note that if you have success with this tutorial, you may also be interested in decoding Meteor M N2 weather satellites which provide much higher resolution images. Also, an alternative tutorial for decoding NOAA satellites that uses rtl_fm can be found here.
YouTube user GaitUutLiern shows an example of receiving NOAA satellite weather images with a RTL-SDR, SDRSharp, a decoding program called WXtoImg and a QFH antenna.
YouTube user nerdsville shows a signal reception comparison of his discone antenna and his home made 1090 MHz tuned ADS-B collinear antenna in this video. The collinear antenna shows a dramatic improvement over the discone.
ADS-B is a broadcast system which can be used to track aircraft like a radar. More information about rtl-sdr and ADS-B here.
Reddit user soooooil has posted a series of images showing his home made Discone antenna made out of wire coat hangers and designed for a minimum frequency of 130MHz. His thread discussing the Discone is here.
A Discone is a good general antenna for the rtl-sdr as they are extremely wideband, and can be expected to be useful over almost the entire frequency range that is tuneable by the the rtl-sdr.
Another page on a home made Discone also designed for a minimum of 130MHz is here with some brief instructions links to design calculators.
Large ships and passenger boats are required to broadcast an identification signal containing position, course, speed, destination, and vessel dimension information to help prevent sea collisions. This system is known as the "Automatic Identification System" or AIS for short. There are dedicated AIS receivers intended to be used on boats, or by hobbyists, but they can be expensive. A radio scanner, or the cheap RTL-SDR software defined radio (or a more advanced SDR such an Airspy) can be used to receive these signals, and with the help of decoding software, ship positions can be plotted on a map.
This tutorial will show you how to set up an AIS receiver with the RTL-SDR. Most parts of this tutorial are also applicable to other software radios, such as the Funcube dongle, Airspy and HackRF, or even regular hardware scanners if a discriminator tap is used, but the RTL-SDR is the cheapest option.
Safety Warning: This probably should not be used a navigational aid on a boat as the field reliability of the RTL-SDR or other software radios is not proven. This guide is intended for land based scanner hobbyists.
Note, tracking ships with AIS is very similar to tracking aircraft with ADS-B, which is another project that may interest you.
An AIS radar example is shown by YouTube user Vinicius Lenci who uses an RTL-SDR, SDRSharp and ShipPlotter. This video also shows what a strong AIS signal sounds like.
YouTube user VoiceOfShortWave has posted a video of his rtl-sdr dongle receiving HF LSB ham radio transmissions at 3.7MHz with excellent performance. He used a homemade VEE antenna, and also a Butterworth filter to help reduce FM band interference. His other video shows the effect of his butterworth filter with 60MHz cutoff turning on.
The RTL-SDR can be used as a super cheap real time air radar. Modern planes use something called an ADS-B (Automatic Dependent Surveillance-Broadcast) Mode-S transponder, which periodically broadcasts location and altitude information to air traffic controllers. The RTL-SDR can be used to listen to these ADS-B signals, which can then be used to create your very own home aircraft radar system. Compared to dedicated commercial ADS-B receivers which can go for between $200 - $1000, the $20 RTL-SDR is very attractive for the hobbyist in terms of price. However, note that the RTL-SDR probably shouldn't be used for ADS-B navigation in a real aircraft for safety reasons.
ADS-B broadcasts at a frequency of 1090 MHz. It has been discovered by the RTL-SDR community, that the RTL-SDR with R820T tuner has the best sensitivity at this frequency. The E4000 and other tuners perform poorly in comparison. So it is recommended that you obtain an R820T tuner if you want to set up ADS-B decoding with the RTL-SDR. Recently there has also been talk about the R820T2 tuner, which seems to have slightly better performance too. See the Buy RTL-SDR dongles page for more information on where to purchase.
We also now note that recently new higher end SDR's like the $199 Airspy have developed very good ADS-B receivers that are several times more sensitive that the RTL-SDR.
In this video, YouTube user Superphish shows a timelapse of air traffic over New Zealand using RTL-SDR, ADSB# and Virtual Radar Server.
