Category: Amateur Radio

Happysat Reviews the QO-100 Bullseye LNB

Thank you to Happysat for reviewing the QO-100 Bullseye LNB which we have available in our store, eBay and Aliexpress. The Bullseye LNB is an ultra stable TCXO (temperature compensated oscillator) based LNB which makes it very good at receiving the narrowband signals on the QO-100 amateur geostationary satellite.

Standard LNBs that are sometimes used for QO-100 are not designed for narrowband signals and hence do not have temperature compensated oscillator which can result in the signals drifting in frequency significantly as the ambient temperature fluctuates. Happysat also notes that the extra stability seems to have increased signal strength on the more wideband DATV reception as well.

First test's on Es-Hail Narrow SSB transponder compared to my old regular sat-tv LNB clearly is showing more signal stability overall.

It does need some time for both the tuner and LNB to get stable, but that's only a few minutes.

Weather conditions shows less "drifting" of the pll where the old LNB was very sensitive of temperature changes, clouds before the sun did have immediately effect on the signal stability.

Some days with storms reception was impossible on SSB Narrow band.

Winter is coming over here so it gets a lot colder and more storms, but I don't expect any problems with this LNB.

Wideband testing DATV reception also shows a more stable signal although its a wider signal then narrowband, it also did increase the signal, e.g. a signal lock happens much faster.

More information about Happysat's setup and his use of the Bullseye QO-100 LNB can be found on his QO-100 website.

Other reviews of the Bullseye LNB include a YouTube video from TechMinds and F4DAV's in depth review on his website.

The Bullseye LNB for QO-100

DragonOS: QRadioLink Radio over IP with an RTL-SDR

DragonOS is a ready to use Ubuntu Linux image that comes preinstalled with multiple SDR program. DragonOS-Focal (the build with the latest updates) has recently been updated to include the latest version of an interesting program called QRadioLink. We've posted about QRadioLink a few times in the past, but if you haven't heard about QRadioLink before this is the description from the website:

QRadioLink is a GNU/Linux multimode SDR (software defined radio) transceiver application using the Internet for VOIP communication (radio over IP), built on top of GNU radio, which allows experimenting with software defined radio hardware using different digital and analog radio signals and a Qt5 user interface.

Its primary purpose is educational (demonstrating radio communications to children at schools), but it can also be customized for low power data communications on various ISM frequency bands. It can also be used as an amateur radio SDR transceiver for experimentation.

The latest DragonOS YouTube video author Aaron demonstrates the use of the QRadioLink Radio over IP feature, when combined with an RTL-SDR and umurmur server. Umurmur is a minimalistic mumble server, which is a Voice over IP (VoIP) application. Aaron runs the RTL-SDR and mumble server on a remote LattePanda single board computer, which then broadcasts music received via the RTL-SDR over a VoIP internet link to a laptop.

DragonOS Focal QRadioLink Radio over IP w/ RTLSDR (GNU Radio, umurmur, lattepanda)

Bullseye TCXO LNB for QO-100 33% Off Sale Ending Soon

On September 15 we began our 33% off stock reduction sale for the Bullseye LNB. The Bullseye is an ultra stable LNB for receiving QO-100 and other Ku-Band satellites/applications. We'll be ending this sale on Wednesday, so if you'd like to purchase a unit please order soon to avoid missing out on the sale price. The current sale price is US$19.97 including free worldwide shipping to most countries. 

To order the product, please go to our store, and scroll down until you see the QO-100 Bullseye TCXO LNB heading. Alternatively we also have stock via our Aliexpress store or on eBay.

For more information about the Bullseye and some reviews please see the original sale post.

The Bullseye LNB for QO-100

TechMinds: The Langstone Project – SDR Transceiver with PlutoSDR

Over on his YouTube channel Tech Minds has uploaded a video introducing and demonstrating the Langstone Project. Langstone is a standalone homebrew SDR transceiver project by Colin Durbridge (G4EML) which at its most basic implementation is based on an Adalm PlutoSDR, Raspberry Pi 4 and 7" LCD touchscreen. 

In the video Tech Minds shows how to install the Langstone Pi4 software on the SD card, and then demonstrates it in action. He also notes that the output power of the PlutoSDR is too low for any real communications, however it is possible to add an amplifier and appropriate band filtering. To help with that, the software makes us of the GPIO pins on the Pi4 which can be used to switch in optional band filters.

Langstone Project - SDR Transceiver using an Adalm PlutoSDR

33% OFF Sale: Ultra Stable Bullseye LNB for QO-100/Es’Hail-2

Back in May we started selling the Bullseye LNB on our store, which is an ultra stable LNB for receiving QO-100 and other Ku-Band satellites/applications. We have recently managed to secure a good deal from the supplier. However, our storage warehouse is now low on space and we are hence running a 33% off stock clearance sale with the unit now priced at only US$19.97 including free worldwide shipping to most countries. 

To order the product, please go to our store, and scroll down until you see the QO-100 Bullseye TCXO LNB heading. Alternatively we also have stock via our Aliexpress store or on eBay.

What is QO-100 and an LNB?

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 also has the world's first amateur radio repeater in geostationary orbit. 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.

What's special about the Bullseye LNB?

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 significantly over time on the order of 300 PPM 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. Software drift compensation can be used to an extent, but it works best if the LNB is somewhat stable in the first place. 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 ready to use with a built in 1PPM TCXO and is cheap.

Reviews

In the past Tech Minds has reviewed this product favourably in the video shown below. In a second video he has also shown how the Bullseye can be combined with a transmit helix in order to create a dual feed uplink + downlink capable antenna.

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

F4DAV has also reviewed the unit on his website, concluding with the following statement:

As far as I know the BE01 is the first affordable mass-produced Ku-band TCXO LNB. These early tests suggest that it can be a game changer for amateur radio and other narrowband applications in the 10 GHz band. The stability and ability to recalibrate should allow even unsophisticated analog stations to tune to a 5 kHz channel and remain there for hours at a time. For SDR stations with beacon-based frequency correction, the absolute accuracy removes the need to oversample by several hundred kHz or to scan for the initial frequency offset.

There are also several posts on Twitter by customers noting good performance

Official Feature List + Specs

Features

  • 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)

Specifications 

  • 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.

Setting up a Raspberry Pi for Ham Radio with RTL-SDR

Over on his blog F4GOH has posted a rather comprehensive tutorial consisting of seven PDF documents showing how he's set up his Raspberry Pi for ham radio and other RF projects. The PDF's essentially form a book that starts with the very basics like preparing an OS for the Pi SD Card, powering on the Pi, finding the IP address and connecting to it with SSH or VNC.

The tutorials move on to installing and using various ham radio programs like Fldigi, WSJT-X , GQRX, GNU Radio, before going on to teach some more Linux concepts. The final two PDF tutorials cover the installation and use of OpenWebRX for remote RTL-SDR use, R2Cloud for decoding weather satellites, and finally Radiosonde Auto RX for decoding radiosonde's on weather balloons.

[Also seen on Hackaday]

Raspberry Pi for Ham Radio

Comparing Shortwave Antennas with an RTL-SDR and FT8 Monitoring

Eric had an inverted L and T3FD antenna set up in his backyard and he wanted to test both at the same time to see which received HF better overall. Rather than relying on subjective 'by ear' measurements he decided to use the digital FT8 mode as his comparison signal. FT8 is quite useful for this purpose as the decoded data includes a calculated signal-to-noise (SNR) reading which is a non subjective measure that can be used for comparisons. It also contains information about the location of the signal which can be used for determining the DX capability of the antenna. 

To perform the comparison he used two or our RTL-SDR Blog V3 dongles running in direct sampling mode, and also added an additional low pass filter to prevent excessively strong TV and FM signals from overloading the input. Each antenna is connected to it's own RTL-SDR, and a modified version of GQRX with remote UDP control is used to switch between multiple FT8 frequencies so that multiple bands can be covered in the experiment. WSJT-X is used for decoding the FT8 packets.

After logging SNR values for several days he was able to plot and compare the number of packets received by each antenna, the maximum distance received by each antenna. His results showed that his inverted L antenna was best in both regards. He then performed a relative comparison with the SNR readings and found that the inverted L performed best apart from at 14 MHz, where the T3FD performed better.

In further tests he also compared the antennas on which signal headings they were receiving best from. The results showed that Erics inverted L was receiving best from one direction only, whereas the T3FD received signals from more headings.

Eric's post includes full instructions on the software setup and also Python code which can be used to replicate his experiments. We think that this is a great way to objectively compare two types of antennas.

Antenna directionality measurements via FT8 received headings

Using a PlutoSDR and Mixer to Transmit 70cm DATV to a 23cm Satellite Receiver

Over on her YouTube channel, SignalsEverywhere, Sarah has uploaded a new video showing how she uses a PlutoSDR, HackRF and mixer to transmit DVB-S digital amateur TV to a standard satellite set top box. In this video the idea is to get a little more range by using the PlutoSDR to transmit in the 70cm band, then upconverting that to the 23cm band right at the satellite receiver. Transmitting at the lower frequency yields a higher power output from the PlutoSDR and less cable loss. The mixer consists of a passive mixer chip and a HackRF is used as the mixer LO signal source as a temporary test solution.

Digital TV Transmitter 70cm ATV to 23cm Satellite Receiver Using a Mixer/Upconverter