Detecting meteor radio echoes using the RTL-SDR USB dongle
At the recent 2015 Society of Amateur Radio Astronomers (SARA) Conference Ciprian Sufitchi (N2YO) presented a paper titled “Detecting meteor radio echoes using the RTL/SDR USB dongle” (pdf). His paper introduces the RTL-SDR, the theory behind forward scatter meteor detection as well as the practical application of the RTL-SDR to meteor detection. Ciprian summarizes meteor scatter as the following:
When a meteor enters the Earth’s upper atmosphere it excites the air molecules, producing a streak of light and leaving a trail of ionization (an elongated paraboloid) behind it tens of kilometers long. This ionized trail may persist for less than 1 second up to several minutes, occasionally. Occurring at heights of about 85 to 105 km (50-65 miles), this trail is capable of reflecting radio waves from transmitters located on the ground, similar to light reflecting from a mirrored surface. Meteor radio wave reflections are also called meteor echoes, or pings.
In the paper he explains how analog TV transmissions are the best for meteor scatter, but unfortunately these been discontinued within the USA. Instead he has been able to use analog TV transmitters from Canada, who still transmit this type of signal. He shows that about half of the USA could use the transmitter he is using for meteor scatter, which is based in Ontario, Canada.
Ciprian is also running a very cool live meteor detection stream on his website at livemeteors.com. His setup is located in the DC Metropolitan area and uses a directional Yagi antenna pointed at the Canadian analog TV tower which is broadcasting at 55.237 MHz. The receiver is an RTL-SDR dongle coupled with SDR# and the ARGO software.
In US and many EU countries the analog TV broadcasting is gone. However, there is DVB-T/T2 digital channels on different frequencies. Has anybody tried to detect meteors at these frequencies?
In Sweden for example, DVB-T/T2 is currently on 490, 618, 642, 706, 730, 746 and 754 MHz.
You can see the relections from the Primary Radar you need just a dont converter and a software for the measurement.
Perhaps a silly question, but can re-entering spacecraft be “seen” using this technique? (If there happen to be any?)
Yes, reentering spacecraft can be easily “seen” using forward scattering.
When the distance between receiver and transmitter is less than 400-500km, reflections from passing planes are also visible (and are a big nuisance for meteor counting).