Tagged: satellite

TechMinds: Building a 3D Printed 2.4 GHz Dual Feed Helix for QO-100

The Bullseye LNB that we have in our store is great for receiving the QO-100 amateur geostationary radio satellite which is available in some parts of the world. However it cannot be used to transmit to the satellite. Over on his YouTube channel Tech Minds shows us how to build a transmit helix antenna that connects to the Bullseye or other suitable LNB, resulting in a dual feed antenna.

The antenna that was built is based on DO8PAT's "Ice Cone Feed" design. The design requires some 3D printed parts for the mount and housing, as well as a copper wire helix, metal reflector and copper matching strip. The Bullseye fits onto the back of the helix mount. Once mounted on a dish Tech Minds shows that he was able to make contact with a friend via the QO-100 satellite with good signal strength.

2.4 GHz Dual Feed Helix Antenna For QO100

Step-by-step Guide to Creating a GNU Radio Based QO-100 SSB Receiver

Thank you to M Khanfar for submitting his video that shows a step-by-step tutorial on building your own SSB receiver in Windows GNU Radio for QO-100 satellite reception.  His tutorial includes adding several tuning sliders in the GNU Radio GUI as well.

QO-100 / Es'hail-2 is a geostationary satellite at at 25.5°E (covering Africa, Europe, the Middle East, India, eastern Brazil and the west half of Russia/Asia) providing broadcasting services. However, as a bonus it has allowed amateur radio operators to use a spare transponder. Uplink is at 2.4 GHz and downlink is at 10.5 GHz. We note that we are selling a "bullseye" LNB in our store which allows most SDR dongles to be able to receive the signal with high frequency accuracy.

GNU-RADIO QO-100 SSB Receiver

DragonOS: Decoding Iridium Satellites with the Iridium Toolkit and an RTL-SDR

DragonOS is a ready to use Linux OS image that includes various SDR programs preinstalled and ready to use. The creator Aaron also runs a YouTube channel that has multiple tutorial videos demonstrating software built into DragonOS.

In his latest video Aaron explores Iridium reception with an RTL-SDR Blog V3, RTL-SDR Blog Active L-Band Patch Antenna and Iridium Toolkit/gr-iridium. Iridium is a satellite constellation that provides services such as global paging, satellite phones, tracking and fleet management services, as well as services for emergency, aircraft, maritime and covert operations too.

In the video he shows how to edit the config file to turn the bias tee on, how to record Iridium data, how to install the AMBE voice decoder, and finally how to decode the Iridum data with Iridium toolkit and play voice recordings.

DragonOS LTS Decoding Iridium satellites with the Iridium toolkit (gr-iridium, RTL-SDR)

An Art Project Involving GOES-16 & NOAA Weather Satellite Reception with SDR

As part of his Masters in Design Studies studies Daniel Tompkins created an art installation called "signs of life" which was focused around his interest in weather satellite reception with an SDR.

FM radio headphones were given out at the door. Each set was tuned beforehand to receive a broadcast from my pre-programmed station.

Visitors were then invited to walk around the room, contemplating the artifacts of the exhibit. A V-dipole at one end of the room captures the broadcast and displays a real-time spectrogram of the radio waves on a small display.

Across the room, a satellite dish points back, creating an alignment across the projected GOES-16 "full-disk" image animation of the Earth. Along the back wall, a few dozen images show demodulated signals from the NOAA 15/18/19 satellites as they passed over Cambridge, Massachusetts in the months of October and November 2018.

The experience demonstrated my interest in tapping into an invisible (wireless) environment of digital information. A USB, software-defined radio (SDR) dongle helped me reach the satellites.

In listening to the transmission, the visitors are engaging in a shared experience, but are somehow still alone and unable to communicate while wearing their headphones. The performance of the exhibition is designed to be a place which simulates the real disconnection of techno-humanity. The "reflecting pool" of the earth spinning on the floor might provide a metaphorical reflection of humanity and progress.

Daniel Tompkins GOES-16/NOAA Art Installation
Daniel Tompkins GOES-16/NOAA Art Installation

This installation reminds us of the "Holypager" live art piece which used a HackRF to receive and print out live pager messages with an aim to demonstrate the amount of personal data being sent publicly over pagers. Another related art piece was the "Ghosts in the Air Glow" project by Amanda Dawn Christie, which saw the HAARP Auroral research facility used to transmit various art pieces to be received from all over the world by people with HF radios. 

GR-HRPT: GNU Radio HRPT Decoder Blocks for NOAA, METEOR, MetOp and FengYun-3 Weather Satellites

Thank you to @Derek33197785 for writing in and highlighting @aang254's work on gr-hrpt, a GNU Radio 3.8 port of HRPT blocks from gr-noaa and other projects. These blocks are for decoding the HRPT signal from weather satellites like NOAA, METEOR, MetOP, and soon FengYun-3. @Derek33197785 writes to us:

[@aang254] made a custom HRPT decoder and ported HRPT blocks for NOAA, METEOR and MetOp to work with gnuradio 3.8 on Linux. Right now it is the only free and open source decoder for MetOp (that works), and he also thinks about implementing FengYun support. I tested the decoder and it works great.

He's also working on extracting the full data from HRPT, not just the AVHRR/MSU-GS imagery but also all the telemetry and other instrument data.

HRPT is a high resolution weather satellite image signal that is broadcast from the same NOAA satellites that provide the more commonly received low resolution APT images at 137 MHz. HRPT is also broadcast by the FengYun-3, Metop and Meteor satellites. However, HRPT transmits at 1.7 GHz, so a high gain dish antenna with motorized tracking mount (or hand guided tracking), LNA and a high bandwidth SDR like an Airspy is required to receive it.

A Metop HRPT Weather Satellite Image (resolution reduced). See @Derek33197785's twitter for the full resolution image.
A Metop HRPT Weather Satellite Image (resolution reduced). See @Derek33197785's twitter post for the full resolution image.

Decoding HIRS Instrument Images from NOAA Weather Satellites

Thank you to Björn Schnabel who has written in to notify us about a website he's created for a program written by Zbigniew Sztanga called NOAA-HIRS-decoder which might be of interest to some RTL-SDR users. Most of us are familiar with the the ability to use an RTL-SDR to receive the APT signal on the NOAA 15/18/19 weather satellites. The APT signal provides a live image of the Earth. If you haven't tried to receive APT yet, we have a tutorial here.

Apart from APT there is also the HIRS instrument data which is transmitted in the Direct Sounding Broadcast (DSB) telemetry signal that is spaced at a slight offset from the APT frequency. According to NOAA, the HIRS instrument is "a discrete stepping, line-scan instrument designed to measure scene radiance in 20 spectral bands to permit the calculation of the vertical temperature profile from the Earth's surface to about 40 km". The SDR# screenshot below shows what the HIRS signal looks like, and to the sides you can see NOAA APT signals.

The NOAA HIRS Signal
The NOAA HIRS Signal (Center Signal)

NOAA-HIRS-decoder makes use of the Project-Dessert-Tortoise NOAA satellite telemetry decoder that we posted about previously which can be used to decode data from most of the other scientific instruments on the NOAA satellites. The HIRS decoder by Zbigniew uses the raw text data produced by the Project-Dessert-Tortoise decoder and converts it into images. Full instructions on setting up the decoder on Windows is provided on the NOAA-HIRS-decoder website, just click the menu icon on the top right of the page, and go to "usage".

The received data contains 10 channels of long wave infrared, 9 channels of medium wave infrared, and one visible light measurement. The software will plot the 20 channels as images that are 56 pixels wide. This is not a high resolution picture, but it is nevertheless valuable data that can be used for scientific or weather prediction purposes.

All 20 NOAA HIRS Channels (Image enlarged from 56 pixels)
All 20 NOAA HIRS Channels (Image enlarged from 56 pixels)

QO-100 Bullseye TCXO Ultra Stable LNB Now Available in our Store for $29.95 with Free Shipping

Back in March we posted about Othernet's release of their "Bullseye" TCXO ultra stable LNB for receiving QO-100 and other Ku-Band satellites. We have decided to now offer these for sale on our store as well.

They cost US$29.95 with free shipping to most countries. We are currently selling it over on our blog store and on our Aliexpress store. The Aliexpress store uses Aliexpress Standard Shipping which may be better for some countries like Poland, Ukraine, etc. As usual, please expect that there could be shipping delays at the moment due to the ongoing global pandemic. Since the US is not covered by QO-100 we will not be stocking Amazon USA.

QO-100 / Es'hail-2 is a geostationary satellite at at 25.5°E (covering Africa, Europe, the Middle East, India, eastern Brazil and the west half of Russia/Asia) providing broadcasting services. However, as a bonus it has allowed amateur radio operators to use a spare transponder. Uplink is at 2.4 GHz and downlink is at 10.5 GHz. Most SDRs do not tune all the way up to 10.5 GHz, so an LNB (low noise block) is typically used, which contains the feed, an LNA, and a downconverter which converts the 10.5 GHz frequency into a much lower one that can be received by most SDRs.

In order to properly monitor signals on QO-100 an LNB with a Temperature Compensated Oscillator (TCXO) or other stabilization method is required. Most LNBs have non-stabilized crystals which will drift over time with temperature changes.  This means that the narrowband signals used on QO-100 can easily drift out of the receive band or cause distorted reception. It is possible to hand modify a standard Ku-band LNB by soldering on a replacement TCXO or hacking in connections to a GPSDO, but the Bullseye LNB is ready to use and cheap.

The Othernet TCXO Ultra Stable LNB for QO-100 and Ku-Band Satellites
The Othernet TCXO Ultra Stable LNB for QO-100 and Ku-Band Satellites

The official product details read:

The Bullseye LNB is the world's most precise and stable DTH/consumer Ku-band down converter. Even a VSAT LNBF costing hundreds of dollars more is no match for the performance of the Bullseye 10K LNB. Each unit is calibrated at the factory to within 1 kHz of absolute precision against a GPS-locked spectrum analyzer. Under outdoor conditions, the stability of the LNB is well within 10 kHz of offset. As a bonus feature, the  Bullseye 10K provides access to its internal 25 MHz TCXO through the secondary F-connector. This reference output can be used to directly monitor the performance of the TCXO over time. 


  • Bullseye 10 kHz BE01
  • Universal single output LNB
  • Frequency stability within 10 kHz in normal outdoor environment
  • Phase locked loop with 2 PPM TCXO
  • Factory calibration within 1 kHz utilizing GPS-locked spectrum analyzers
  • Ultra high precision PLL employing proprietary frequency control system (patent pending)
  • Digitally controlled carrier offset with optional programmer
  • 25 MHz output reference available on secondary F-connector (red)


  • Input frequency: 10489 - 12750 MHz
  • LO frequency 9750/10600 MHz
  • LO frequency stability at 23C: +/- 10 kHz
  • LO frequency stability -20 - 60C: +/- 30 kHz
  • Gain: 50 - 66 dB
  • Output frequency: 739 - 1950 MHz (low band) and 1100 - 2150 (high band)
  • Return loss of 8 dB (739 - 1950 MHz) and 10 dB (1100 - 2150 MHz)
  • Noise figure: 0.5 dB

We note that an external bias tee power injector is required to power the LNB as it requires 11.5V - 14V to operate in vertical polarization and 16V - 19V to operate with horizontal polarization. The bias tee on the RTL-SDR Blog V3 outputs 4.5V so it is not suitable.

There has also been an excellent review by @F4DAV and a video review by Techminds which we show below.

Ultra Stable Bullseye LNB For QO-100 Es Hail2 10 kHz

Understanding PLLs and their Importance when Receiving/Transmitting on QO-100

Over on YouTube Andreas Speiss has uploaded a video that explains what the geostationary QO-100 satellite is, and explains about the parts needed to receive and transmit to it. In particular Andreas goes into depth explaining the low noise block (LNB), and the PLL inside it. A PLL or phase locked loop is a common design used in RF electronics as it allows us to increase the frequency of crystal oscillators.

This PLL explanation ties into the fact that most commercial LNBs available do not have a stable enough crystal oscillator to properly receive or transmit the narrowband amateur radio signals used on QO-100. A PLL can increase the frequency of a crystal, but it will also increase the frequency drift and jitter/phase noise of the crystal. He notes that in later videos he'll show how to modify the LNB to improve these factors. We note that a commercially available stable LNB is the Bullseye LNB which we have posted about previously.

QO-100 Satellite Receiving Technology. And Explanation of a PLL