Tagged: c-band

Video Demonstrating C-Band AERO Aircraft Tracking

AERO is essentially the satellite based version of aircraft ACARS. AERO's L-band signals contains short ground to air messages with things like weather reports and flight plans. The C-band signals are the air to ground portion of AERO and more difficult to receive as they require an LNB and large dish. However they are much more interesting as they contain flight position data, like ADS-B.

Over on YouTube Tomasz Haddad has uploaded a video of C-band AERO being received from the Inmarsat 3 F2 (Atlantic Ocean Region – East (AOR-E) 15W satellite. He uses a 1.80m motorized satellite dish with Kaonsat KS-N201G C-band LNB, a Prof 7301 PCI satellite card (to power the LNB) and an RTL-SDR V3. The C-band LNB translates the high C-band frequencies down to L-band which is receivable with an RTL-SDR. He notes that the LNB drifts quite a lot as it is not frequency stabilized.

With the signals received by his setup he's able to use the JAERO decoding software together with Virtual Radar Server to plot aircraft positional data using Virtual Radar Server. The plotted aircraft are mostly all in the middle of the ocean or in remote areas, which is where C-band AERO is normally used due to the lack of ground ADS-B stations.

Inmarsat 3 F2 15W C Band AERO Reception Using Jaero And Virtual Radar

Potentially Receiving up to 10 GHz with an RTL-SDR and Multiple SUP-24000 Downconverters

Back in 2016 KD0CQ discovered that a $5 DirectTV device with model name SUP-2400 could be used as a downconverter with an RTL-SDR for receiving frequencies of up to 4.5 GHz. A downconverter is a device that converts high frequencies such as 4.5 GHz down into a frequency actually receivable by the RTL-SDR. The SUP-2400 is able to be modified into a useful downconverter by opening it up and manually removing some mixing harmonic filters.

In his latest post KD0CQ shows how you could combine four modified SUP-2400 downconverters to create a quarduple conversion mixer which allows you to receive up to 10 GHz. The post goes into the mixing math and practicalities of this idea. KD0CQ writes that some amplification will most likely be required to push the signal through, and in the past he’s managed to receive up to 7.5 GHz.

The SUP-2400 Directv upconverter that can be converted into a downconverter.
The SUP-2400 DirecTV device that can be converted into a downconverter.

Using the SUP-2400 Downconverter with an LNA and RTL-SDR to Receive 2.4 GHz Video

Earlier in June YouTube user T3CHNOTURK posted a video demonstrating him receiving signals above the maximum 1.7 GHz range of the RTL-SDR by using a modified SUP-2400 downconverter. Back in April it was discovered by KD0CQ that a $5 DirecTV SUP-2400 circuit could be modified and turned into a downconverter for use with the RTL-SDR.

Now T3CHNOTURK has uploaded a new video showing more demonstrations of the RTL-SDR + SUP-2400 combo in action. This time he adds a PGA-103 based LNA to boost the signal strength, which gives him better effective range. In the video he shows reception of a wireless keyboard once again, and then goes on to show him receiving 2.4 GHz analog PAL video using the RTL-SDR program TVSharp. The picture is not particularly clear, but it is a decent demonstration.

RTLSDR, TVsharp 2.4 Ghz video receiver moded SUP-2400 & pga-103 LNA

A Demonstration of the RTL-SDR Receiving WiFi and 2.4 GHz ISM with a Modded SUP-2400 Downconverter

Back in April we posted about how KD0CQ found that he could receive signals up to 4.5 GHz with an RTL-SDR by using a $5 downconverter for DirecTV called the SUP-2400. The RTL-SDR can only receive up to a maximum frequency of about 1.7 GHz, but the SUP-2400 downconverter can be modified to convert frequencies at around 2.4 GHz down into a range receivable by the RTL-SDR.

When we first posted the story the instructions for modifying the SUP-2400 to use as a downconverter weren’t uploaded yet, but they are now. The modification requires decent soldering skills as it involves desoldering a few small SMD components and bridging some points with wires.

Over on YouTube user T3CHNOTURK has uploaded a video showing the downconverter in action. With the SUP-2400 downconverter and RTL-SDR he is able to receive some WiFi at 2.447 GHz as well as signals from a wireless keyboard at 2.465 GHz

RTLSDR Receiveing wifi & 2.4 ghz ism band with moded SUP-2400 Downconverter

Receiving up to 4.5 GHz with an RTL-SDR and a $5 Directv Downconverter

KD0CQ has recently been experimenting with trying to receive signals at frequencies of up to 4.5 GHz with an RTL-SDR and downconverter. Since a typical R820T/2 RTL-SDR’s maximum frequency limit is about 1.7 GHz, an external downconverter circuit is required. A downconverter converts high frequencies down into the range receivable by the RTL-SDR. For example a downconverter with a 2.4 GHz local oscillator would convert a 3.5 GHz signal down to 1.1 GHz, which can be easily received by an RTL-SDR.

The secret to doing this cheaply is revealed by KD0CQ. He shows that a very cheap $5 Directv SUP-2400 upconverter can be converted into a 2.4 GHz downconverter simply by removing some filters. He writes that he hasn’t uploaded the full set of steps to modify the SUP-2400 yet, but he intends to do so in the near future.

There is also a discussion about this mod on Reddit. Several posters have been discussing what applications a cheap downconverter could open up. Some mentioned applications include receiving various satellites in the C/S bands, DECT cordless phones @ 1.9 GHz, SiriusXM satellite radio @ 2.3 GHz, ISM @ 2.4 GHz, RADARs, RC aircraft control/telemetry/video and ham beacons.

The SUP-2400 Directv upconverter that can be converted into a downconverter.
The SUP-2400 Directv upconverter that can be modified into a downconverter.
$5 Microwave Downconverter for the RTLSDR KD0CQ

YouTube video showing Inmarsat C-Band AERO Reception

Last week we posted how programmer Jonti had successfully implemented a C-Band AERO decoder into his JAERO software. C-band AERO signals are the earth downlink portion of AERO. Planes transmit data upwards towards the satellites and then the Inmarsat C-band transmitter re-transmits the information back to a basestation on earth. This is different to the L-band AERO signals which are signals transmitted from the satellites to the aircraft. C-band signals are interesting because they contain plane position info, and so can be used to track aircraft much like what is done with ADS-B reception, but over a much larger area. However, C-Band signals are much more difficult to receive as they are at 3.616 GHz and require a 1.8m or larger satellite dish.

Over on YouTube user AceBlaggard has uploaded a video showing an example of C-Band signals being received with an Airspy SDR and being decoded with the new version of JAERO. About the hardware used AceBlaggard writes:

Hardware is a 1.8M PF dish and Titanium Satellite C1 PLL LNB feeding a Prof-Tuner 7301 sat card which loops out to an Airspy SDR.

Inmarsat C Band aero feed.