Tagged: satellites

Talks from the AMSAT-UK RSGB 2017 Convention

The Radio Society of Great Britain (RSGB) and AMSAT-UK recently presented a number of talks at their latest convention held in October of this year. Some of the talks are SDR related and are interesting for those interested in satellite reception. A couple of interesting SDR related talks are presented below, and the rest of the talks can be accessed on their YouTube page.

Software defined radio for the satellite geek - Alex Csete OZ9AEC

In this talk Alex Csete (Oz9AEC) who is the programmer behind the popular GQRX software that is often used with RTL-SDRs discusses his latest work and some of his experiences with writing software for SDRs.

Going to space the libre way - Pierros Papadeas, Libre Space Foundation

In this talk Pierros Papadeas who is the founder of the Libre Space Foundation discusses their SatNOGS project. SatNOGS is a project that uses RTL-SDRs in custom 3D printed home made satellite tracking ground stations. It aims to enable easy access to live satellite data online by significantly increasing ground station coverage.

Testing a 16x RTL-SDR V3 WebSDR System for the Satcom Band

Over on Twitter Denis (@uhfsatcom) has recently been teasing us with photos of his 16 dongle RTL-SDR V3 setup. The system looks like it's designed to be a satcom band WebSDR receiver. 

The satcom band is around 240 - 270 MHz and mostly consists of various military satellites that act as simple repeaters which are often hijacked by pirates. WebSDR is a piece of software that allows for online web streaming of SDR radios. Users from all over the world can listen in if made public. Denis has also uploaded a short video showing a test of 8 dongles running and receiving the satcom band on his WebSDR system.

We look forward to hearing more updates on this project!

Modded SUP-2400 Downconverters now Available at RXTXDX.com for $25

Last week we posted about KD0CQ’s interest check on his ready to go modded SUP-2400 downconverter. Interest was strong so the unit is now available for sale on a store he’s just set up at RXTXDX.com. The ready to go unit costs $25 USD including a 9V battery plug and F->SMA or MCX adapter.

Last year KD0CQ discovered that the SUP-2400 is a cheap $5 – $10 DirecTV (US satellite TV) module which can be hand modded into a downconverter for the RTL-SDR. A downconverter allows you to listen to frequencies above the maximum frequency range of the RTL-SDR by converting frequencies down into a range receivable by the RTL-SDR (or of course any other SDR). The modified SUP-2400 allows to you listen up to just over 4 GHz.

The SUP-2400 modification is moderately involved and requires soldering and desoldering SMD pieces, so this product is great for anyone who just wants a cheap and low cost downconverter which is ready to go. And at $25 USD it’s still very good value. Shipping within the USA is $7.75, and internationally it is about $13.50.

The modified SUP-2400 Downconverter
The modified SUP-2400 Downconverter

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.

Building an S-Band Antenna for the HackRF

Mario Filippi, a regular contributor to our blog and to the SDR community recently wrote in with an article showing how he built an S-Band (2 – 4 GHz) antenna for use with the HackRF. Of course the antenna can be used with any other SDR that can receive in this range, or with an RTL-SDR and downconverter. We post his article below.

S -Band Antenna for use with the HackRF One
Author: Mario Filippi, N2HUN

Ever since purchasing a HackRF One, which receives from 1 MHz – 6.0 GHz I’ve always wanted to explore the world above 1 Gig, specifically the 2.0 – 2.7 GHz portion of the S-band. This portion of the band is populated with satellite communications, ISM, amateur radio, and wireless networks. A good, homebrew antenna for S-band was needed, so with parts mostly from the junk box, a 2250 MHz S-band right hand circularly polarized omni-directional antenna was built. Below is a step by step tutorial on building this antenna. Plans were from UHF-Satcom’s site.

The final S-band antenna
The final S-band antenna

Continue reading

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.

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

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.