Saveitforparts: Hacking an Motorized RV Satellite Dish for Tracking LEO Satellites

Over on the saveitforparts YouTube channel, Gabe has uploaded a new video showing how he's hacking an old motorized Wineguard RV satellite dish for tracking low earth orbit satellites, such as the NOAA and Meteor weather satellites as well as the US Military's DMSP system.

The motorized RV satellite dish was originally intended for tracking TV satellites, but by connecting to the serial port on the control unit, Gabe is able to control the satellite dish through his own code.

In this video I'm creating a motorized satellite tracker for S-Band signals. S-Band includes NOAA weather satellites and the US Military's DMSP system (it's also the radio band for WiFi, which I might look at later).

I'm using a Winegard brand "Trav'ler" antenna designed for use on campers and recreational vehicles. It has a built-in three-axis motor system for pointing at TV satellites, but I wanted to use it for tracking satellites closer to earth. Since a low-orbit satellite like NOAA 18 or DMSP passes overhead in about 10 minutes, I need to move the dish faster and more precisely then it was intended for.

This project is still ongoing, and I don't yet have the code up on Github. When I do, it will be available at https://github.com/saveitforparts/ alongside the code for some similar antennas I've hacked in the past.

The serial cable I'm using is described here: https://saveitforparts.wordpress.com/2023/12/29/another-portable-radio-telescope/

Modifying RV Satellite Dish To Track Low-Earth-Orbit Satellites

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Setting up a Dual RX System with an SDR and Ham Radio Rig via an SDRSwitch

There are two common options when using an SDR together with a ham radio rig. You can either create an IF tap within your ham radio and connect the SDR to that, or connect the SDR directly to the antenna via a switch that switches the SDR out when transmitting.

Over on YouTube, Ham Radio DX has uploaded a video discussing the latter option and revealing its advantages. In the video, he mentions results by HB9VQQ that show that connecting an Airspy HF+ directly to an antenna via an SDR switch from SDRSwitch.com results in 60% more spots on WSPR, compared to using an IF tap from an FT450D ham radio rig.

He goes on to explain and demonstrate his setup and the recommended switch that he is using, which is the SDRSwitch by N2EME, available at SDRSwitch.com. He notes that this switch is recommended due to its very low insertion loss and high isolation specifications and compares it against an MFJ switch, which has some rather terrible specifications.

Add a SDR Receiver to ANY Ham Radio Rig!

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A Detailed Guide to Setting up RTL1090 for ADS-B Decoding

RTL1090 is a popular ADS-B decoder program that works with RTL-SDR dongles. With it, you can receive ADS-B signals from aircraft, decode them, and then pass that data to a mapping program to plot aircraft positions on a map.

Recently, RTL-SDR.COM reader Frank wrote in and wanted to share with us a detailed guide he's written on the process of setting up RTL1090. The guide starts by showing how to set up the RTL-SDR dongle by installing the WinUSB drivers via Zadig. It goes on to show how to download, unzip, and run RTL1090. Guides for RTL1090 V1, V2, and RTL1090 Scope are shown separately.

RTL1090 Scope
RTL1090 Scope
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SignalSurge – An open source bandpass filter with selectable LNA for the VHF and UHF bands

Thank you to Rodrigo Freire for writing to us and sharing his project called 'SignalSurge'. The SignalSurge project started when Rodrigo discovered that adding an RTL-SDR Blog FM Bandstop filter to his Yaesu FT-991A significantly improved his reception in the 2-meter band.

An FM bandstop filter can improve reception by reducing the power of strong broadcast FM signals, which can overload the front end of radios, causing the desensitization of signals on other bands.

This finding led Rodrigo to design SignalSurge, a bandpass filter for VHF and UHF bands, with a selectable LNA. The design includes selectable 2m and 70cm bandpass filters, a selectable 15dB LNA, automatic LNA shutdown when the radio is transmitting, and ESD protection. A 50W relay gives the ability to select between filters and switch the LNA in or out.

The design is entirely open source and available on the SignalSurge GitHub.

SignalSurge Schematic
SignalSurge Schematic
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Saveitforparts: Testing a 3D Printable Satellite Antenna for NOAA, Meteor and other Polar Orbiting L-Band Satellites

Over on the saveitforparts channel, Gabe has uploaded a video showing a 3D-printable helicone antenna for receiving weather images from polar-orbiting L-band satellites like NOAA and Meteor. This antenna has become popular in the community as it is relatively easy to build, lightweight, and small enough to be handheld. The 3D model files are available on Thingiverse.

In the video, Gabe shows that initially, he had multiple failed print attempts on the helical scaffold due to the legs warping. He was able to solve this and get a working print by slightly modifying the 3D model to have additional center supports. He then goes on to show the rest of the build, which involves coiling the helix antenna, cutting the reflector out of sheet metal, screwing together the reflector supports, and mounting the reflector mesh.

Finally, he shows that he was able to get successful image reception from NOAA HRPT satellites using hand tracking, with a phone running an RTL-SDR and SatDump for tracking and decoding.

This 3D-Printed Satellite Antenna Is Fantastic!

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Demonstrating the Effect of Square Wave Harmonics with a HackRF and RTL-SDR

Over on YouTube Paul from 'Tall Paul Tech' has uploaded a video that explains and demonstrates the effect of square wave harmonics using a HackRF and RTL-SDR.

Paul starts by using GNU Radio to explain how square waves are created from a set of sine waves, and how a signal can essentially turn into a square wave if it is too strong and clipping the analog to digital converter (ADC). The result for your SDR is that harmonics of strong signals can show up at incorrect frequencies.

Later in the video, Paul shows this effect using a HackRF and RTL-SDR.

Effect of harmonics and interference from clipping and square waves

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Sn0ren Tests out the KrakenSDR

Over on his YouTube channel, sn0ren has uploaded a video showing his experience with the KrakenSDR. If you weren't already aware, KrakenSDR is our 5-channel coherent radio based on RTL-SDRs, and it can be used for applications like radio direction finding. It can currently be purchased from Crowd Supply or Mouser.

In the video, sn0ren explains radio direction finding in general and then goes on to show how to set up and use KrakenSDR. Sn0ren writes:

Wireless communication is inherently anonymous. There is no way of knowing who transmitted a signal if they do not identify. And there is no way of knowing where that signal is transmitted from. Unless you actively track it down. KrakenSDR is a radio direction finding device that uses an array of antennas and synchronised receivers to track down the position of a given radio transmission and lead you directly to its physical location.

Track Down Radio Transmitters / KrakenSDR

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Saveitforparts: Receiving the Bitcoin Blockchain from the Blockstream Satellite Network

Over on his YouTube channel 'saveitforparts' has uploaded a new video showing how he was able to download the Bitcoin blockchain via the Blockstream Satellite network. The Blockstream satellite network allows people in remote communities without an internet connection to receive the entire Bitcoin blockchain via satellite. With the blockchain Bitcoin users can confirm if a payment to them has been made.

After several failed attempts, he was finally able to receive and decode the signal using a fold-out satellite dish with an LNB and an RTL-SDR Blog V4. He also attempts to use the encrypted messaging feature on the blockstream satellites. However, while the message appears to have been received, he was unable to actually view the message due to an error. He writes:

A while back I heard about the Blockstream Satellite network, which claims to offer real-time streaming of the Bitcoin blockchain to anyone with a satellite dish. While I still don't understand cryptocurrency, I thought the satellite part of this sounded interesting!

It took a while to locate the correct satellite (Galaxy 18 in North America), and to get the software working, but eventually I was able to start downloading the blockchain file. What to do with it next, I have no idea!

I also tried sending messages through the satellite, but unfortunately I wasn't able to decode them on the receiving end. I gave up on this since I didn't want to spam everyone on the global network!

You can find out more about the Blockstream Satellite system on their website: https://blockstream.com/satellite/

And you can find instructions on using the system here:https://blockstream.github.io/satellite/doc/sdr.html

I used https://www.dishpointer.com/ to help align my antenna.

I also used https://www.lyngsat.com/ and https://www.satbeams.com/ to identify which satellites I was detecting.

I Found Bitcoin On A Satellite In Space

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