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.
A new digital noise reduction plugin for SDRSharp has been released. It is packaged as part of the SDRSharp binaries. Head to the SDRSharp downloads page, and download and use the automated installer for rtl-sdr under the heading “Important note for RTL-SDR users”.
Then in SDRSharp, simply click “Enabled” in the Digital Noise Reduction plugin window and adjust the slider until you get good results. In testing I found significant improvements in noise reduction.
Blogger and Amateur Radio enthusiast N4JTC has posted a guide on setting up a satellite receiving station with the rtl-sdr. Originally the guide was intended for receiving the PhoneSat test satellites, but they have now gone offline after a week as planned. But, the guide is still useful for any current and future satellites.
The recent launch of the PhoneSats got my SDR and satellite juices flowing again. This time I decided to automate things because work seems to get in the way of my satellite listening fun. I found a combination that works great and incorporates FREE software and inexpensive hardware.
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.
YouTube user ek6rsc has posted a video showing one week of meteor scatter observation at 59.25MHz using the rtl-sdr and the HROFFT software. More information about meteor scatter observations can be found at the page of The International Project For Radio Meteor Observation. The rtl-sdr is handy as a cheap monitoring tool for purposes such as this. From Wikipedia meteor scatter is described as follows.
Meteor burst communications (MBC), also referred to as meteor scatter communications, is a radio propagation mode that exploits the ionized trails of meteors during atmospheric entry to establish brief communications paths between radio stations up to 2,250 kilometres (1,400 mi) apart.
Digital Audio Broadcasting (DAB) is a digital method for broadcasting radio stations. The rtl dongles official driver has DAB decoding capabilities. But when the rtl dongle is used as a software radio, this capability from the original drivers can not used.
SDR-J is a SDR package for Windows and Linux which is capable of receiving FM radio and decoding DAB radio completely in software. YouTube user Superphish shows a video of SDR-J decoding and playing DAB music with a rtl-sdr dongle.
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 opilarczyk has posted a video comparing HF performance of the rtl-sdr with the direct sampling mod at 7MHz with WebSDR, an online SDR streaming site. The comparison shows how the direct sampling mod is extremely susceptible to broadcast FM interference.
