1000 posts on science, engineering and STEM education

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SDR# Sharp Ubuntu

1 minute read

SDR# Sharp compiles and runs using Mono on Ubuntu 18.04 and 16.04

Echolink on Android

1 minute read

How to use Echolink on Android, a robust Echolink option for those times you forgot to bring your radio.

Quickstart BU SCC compute cluster

less than 1 minute read

These comments are specific to Boston University Shared Computing Cluster, but may have corollaries on your compute cluster/supercomputer

Ridesharing walk to pickup

less than 1 minute read

Uber Pool Express in Boston require walk to easier pickup locations. Lyft in Washington, D.C. suggests better pickup points.

eLoran te US Senate bill S.2220 2017

less than 1 minute read

Although not actually requiring eLoran, the bipartisan Senate bill has a finite chance of passing and making an important GPS backup.

Kraken minimum trade size

less than 1 minute read

Cryptocurrency exchanges typically have minimum trade sizes to avoid excessive transaction volume slowing down the system.


Why upgrade to Python 3.7?

2 minute read

Python 3.7 adds performance and features useful for many Python users–here’s a few highlights.

Android Wear 8 Oreo

1 minute read

Describes new features on Android Wear 8 Oreo, especially for LG-W280 Watch Sport.

AGU FM2017 Python lunch notes

less than 1 minute read

Thoughts from leaders in geoscience Python, from numerous government agencies and research institutes.

Install Intel Python 3.6

less than 1 minute read

How to install Intel Distribution for Python 3.6 2018, and comparison to Anaconda Python.

Aspell user dictionary location

less than 1 minute read

The aspell program is used by many software packages as a spellchecker. Here’s how to find the user dictionary file location.

Don’t repair computer power supplies

less than 1 minute read

End users generally shouldn’t repair power supplies. They are a consumable, wearable part that requires expertise to safely repair.

Install Python3 on CentOS

less than 1 minute read

How to install Python 3.6, pip, numpy, etc. on CentOS with EPEL or Anaconda Python.

WSJT-X on Ubuntu

2 minute read

How to operate JT65/JT9/FT8/WSPR powerful weak-signal modes on Linux. Operating strategies described.

Disable Windows error popup

less than 1 minute read

How to disable the Windows program error popup that stops tasks from continuing or restarting.

FMeXtra/VuCAST vs. HD Radio

4 minute read

How field-proven, economical FMeXtra fails vs. HD Radio. Possible FMeXtra rebirth as open FM digital SCA.

No more Amtrak gate dragons

1 minute read

Amtrak is removing gate ticket checks from major stations, and instead scanning tickets once aboard at the station.

Travis CI examples

1 minute read

Quick examples of Travis-CI – a system that runs your self-test on each git push. It can save you from hard to find bugs later.

USA 2G cellular shutdown

1 minute read

Possible 2G GSM shutdown impacts vis cheap replacement 4G modems. US 2G shutdown targeted for 2019.

Free 2-D CAD overview

1 minute read

Comparison of AutoCad drop-in compatible popular free 2-D CAD packages DraftSight, QCAD and LibreCAD.

MURS VHF vs. 900 MHz modems

1 minute read

Long-range license-free modems at VHF (151 MHz) MURS are compared with globally-usable 900 MHz modems.

Amtrak Dunkin’ Donuts coffee

less than 1 minute read

Dunkin’ Donuts coffee first came to Amtrak Acela in April 2017, and has now expanded to Northeast Regional trains from Richmond, VA to Boston, MA.

Making/using wineprefixes

less than 1 minute read

Use distinct wineprefixes to use complicated Windows programs on Linux via WINE.

Install Zello app on Linux

less than 1 minute read

How to install Zello on Linux. Zello mobile & desktop apps allow Nextel-like PTT group communications.

RTL2832 ADS-B decoder

less than 1 minute read

How to decode/log/display ADS-B aircraft transponder data with $20 RTL2832 USB receiver & Raspberry Pi.

AIDA tools

less than 1 minute read

Work with AIDA Tools auroral tomography in modern Matlab versions

Zenodo data upload speed

less than 1 minute read

My uploads of large datasets to Zenodo (or other such sites) are often restricted by upload speed.

Basler Pylon 5 API from Python

less than 1 minute read

How to control Basler cameras from Python using the Pylon 5 API via Cython in Linux, Mac, Windows.

Bloomberg Radio now on 106.1 FM in Boston

2 minute read

The FCC’s 2009 ruling allowing AM stations to simulcast on FM permits Bloomberg Radio to escape interference endemic to AM radio with a 99 watt FM transmitter.

What can a harmonic radar do?

2 minute read

Sampling of the numerous questions I get on harmonic radar, from Fortune 100 companies on down over the past decade.

upgrading Scipy via pip

less than 1 minute read

You can install Scipy the quick way via conda, or the general way via pip.

Bluetooth speaker with FM radio

less than 1 minute read

I consider having an FM radio in a Bluetooth speaker essential, as well as having SD card and 3.5mm input. The Simpowel V8 fulfills these needs for under $40.

Fortran gdb/gdb-ia Debugging

1 minute read

How to debug Fortran code for one accustomed to Matlab/Python debugging. Cheat sheet for gdb or Intel gdb-ia debuggers.

Bluetooth Sound on Linux

less than 1 minute read

Quick setup Bluetooth sound (speaker) on Linux PCs and embedded single-board computers, including the Intel Edison.

Making GNU Coreutils wc word count faster

less than 1 minute read

A colleague did some very interesting work in speeding up gnu-coreutils wc. Here’s his code–would anyone want to make a pull request to Coreutils?

Loading WSPR raw audio data

less than 1 minute read

WSPR raw data in the form of audio files is highly useful for radio science analysis. Here’s how to load these files into Python.

Fix inability to type in Spyder IDE over VNC

less than 1 minute read

Some VNC setups are unable to remotely use Spyder IDE over VNC–you can use the mouse, but not the keyboard. Here’s how I fixed this problem using TurboVNC.

Cygwin on Windows 10

less than 1 minute read

Cygwin compliments Windows Subsystem for Linux capabilities. A key Cygwin advantage over WSL is the ability to run as a service.

Overleaf with Github

2 minute read

Use Github with Overleaf, as Overleaf corrupted my document but with Git I could recover it post facto. Using Git a priori stops such corruption.

Tetris on Fortran using Ncurses

less than 1 minute read

Legacy plotting/graphics libraries exist for Fortran, but why not exploit C libraries while doing the work in Fortran? Result is TETRAN game.

Python PyGame installation

less than 1 minute read

How to install PyGame for easy sound playback and live keyboard callbacks in Python.

SMBv1 WannaCry Detection and Mitigation

1 minute read

Unpatched Windows systems may be vulnerable to SMBv1 attacks, of which WannaCry is the latest. Here’s how to detect if you’re patched and how to patch.

Where are Matplotlib release notes

less than 1 minute read

Matplotlib release notes tell you about bugs fixed and features added. They are located on the Github releases page.

Finding your Uber passenger rating

less than 1 minute read

Low Uber passenger ratings make drivers not want to pick you up. How to check and increase your Uber rider rating.

Convert RIS to Bibtex

less than 1 minute read

How to convert RIS citations to .bib BibTeX/LaTeX format quickly. Also how to create PDF from .bib

How to setup Astrometry.net program

less than 1 minute read

How to get azimuth/elevation for each pixel of a sky image using Astrometry.net blind registration of astronomical/auroral images.

Force apt to IPv4

less than 1 minute read

Sometimes a remote host or your ISP is temporarily misconfigured with regard to IPv6. You can force apt to use IPv4 as follows.

Python NI-DAQmx official support

less than 1 minute read

In March 2017, National Instruments released a complete Python API via ctypes for NI-DAQmx–here’s how to set it up.

Numpy N-D rot90 flip

less than 1 minute read

Numpy 1.12 adds pathlib support throughout, and upgrades rot90 and flip to handle N-D arrays–big improvement.

Coefficient of variation from uranyl slide

less than 1 minute read

A uranyl microscope slide provides spatially uniform fluorescence, enabling flat-fielding/normalization of the illumination and optical system at once.

How to install VisPy OpenGL for Python

less than 1 minute read

VisPy uses PyOpenGL for beautiful, fast 3-D and 2-D plotting from Python and Numpy arrays. Here’s an easy way to setup VisPy–you don’t need a discrete GPU.

How to install Glumpy OpenGL for Python

less than 1 minute read

Glumpy uses PyOpenGL for beautiful, fast 3-D and 2-D plotting from Python and Numpy arrays. Here’s an easy way to setup Glumpy–you don’t need a discrete GPU.

CW Radar using Red Pitaya and GNU Radio

2 minute read

The simplest waveform a radar can use is a continuous unmodulated tone. Here is an example GNU Radio-based CW software defined radar using Red Pitaya.

Install Andor Neo SDK3 in Windows

less than 1 minute read

It’s straightforward to install the Andor Neo SDK3 in Windows, and compile with MinGW instead of Microsoft Visual Studio.

Calibrating the PiRadar range and Doppler

2 minute read

Calibrating a radar requires controlled conditions. That’s very difficult at HF, so we can use low-band VHF with the procedure and material described.

Convert PDF to SVG

less than 1 minute read

How to convert PDF to SVG vector graphics for high resolution diagram on a webpage without download.

Switch from IDL to Python

1 minute read

Python is a high performance language for data analytics tasks common to science and engineering. Simple guide to transition from IDL to Python with examples.

Radar transponder for radar calibration

less than 1 minute read

When you need a point target in high clutter environments, a radar transponder is good to consider. Here’s how to make a software-defined transponder.

Basic PiRadar functionality test

1 minute read

Essential verification of radar system elements can take place separately at a distinct frequency to save cost and time.

rsync to EXFAT drive

less than 1 minute read

gives correct rsync command line options to sync with ExFAT formatted drive.

pgrep pkill fulltext process name search

less than 1 minute read

pgrep only searches the first 15 characters by default. Adding the -f option makes pgrep search the whole process name, which is normally preferable.

Control Dropbox from Linux Terminal

less than 1 minute read

If your remote graphical desktop doesn’t have the Dropbox dæmon running, you can control Dropbox easily from an SSH prompt.

Project Fi technical aspects

3 minute read

Project Fi uses three LTE carriers plus VPN WiFi. Here are some practical details on how the Project Fi aggregating MVNO works.

PySide in Anaconda3

less than 1 minute read

How to correct a Matplotlib ImportError when using QT/PySide.

Build POV-Ray 3.7

less than 1 minute read

How to compile POV-Ray on Linux and an example.

Compile Matlab code to run on any PC

1 minute read

How to compile Matlab code to an executable, so that Matlab isn’t needed to run the .m file. The free Matlab Compiler Runtime is needed on the non-Matlab PC.

Fixing Ubuntu no Wifi on resume from suspend

less than 1 minute read

Ubuntu 16.04 has a long-standing NetworkManager bug where on some PCs Wifi doesn’t work upon resuming from suspend. Here are some workarounds and notes.


Qi charging review

1 minute read

Qi falls short compared to modern quick-charging from USB-PD.

Completely undo errant git remote push

1 minute read

For any Git remote repo (e.g. Github/Gitlab), you can undo (delete from git history) the last or previous pushes to eliminate huge/numerous/wrong files pushed.

Disable text wrapping in nano

less than 1 minute read

How to turn off Cygwin nano default word wrap. This avoids breaking configuration files and Python scripts.

Setup Red Pitaya for GNU Radio

less than 1 minute read

You need Pavel Demin’s custom Red Pitaya image on a micro SD card, and GNU Radio on your PC to start.

OMTI auroral imager at RISR data download

less than 1 minute read

The OMTI imager data has led to a number of publications used with the RISR Resolute Bay Incoherent Scatter radar. Here is how to get that OMTI data.

Remove default limited Ubuntu web browser

less than 1 minute read

The default Ubuntu web browser is set by default to open links. I find it uselessly limited, so here’s how to remove the Ubuntu web browser.

SoundBot Bluetooth headphones

2 minute read

Detailed review of Soundbot SB240 and SB220 Bluetooth headphones–noting some problems with modern Bluetooth source devices.

Mount broken .vdi VirtualBox disk image

less than 1 minute read

How to rescue a .vdi disk image if your VirtualBox OS won’t boot anymore with this procedure. This allows rescuing virtual machine files you created.

Android Wear autonomous via Wifi/LTE

1 minute read

How to use Android Wear smartwatches semi-autonomously with non-Android, non-iOS devices. For example Android Wear with BB10 or Windows Mobile device.

How Paging Coasters work

2 minute read

Technical explanation of paging coasters in the 27 MHz and UHF bands, including antennas and interference.


Societal Engineer’s e-Bookshelf

less than 1 minute read

eBooks relevant to computer engineers and other STEM fields incl. education, humanitarian and public services.

Matlab missing compiler error

less than 1 minute read

Fix Matlab errors on loading shared libraries loadlibrary() by telling Matlab your compiler path.

People Who Scale

less than 1 minute read

Blog series on people who scale in business and life, helping pick the most robust and reliable business partners.

Micro SD mounting read-only

less than 1 minute read

Troubleshoot faulty SD cards vs. adapters by swapping out. Sometimes the cards fail in a no-read mode.


Compacting VirtualBox VDI files

1 minute read

How to reduce the size of huge VirtualBox VDI images. Compact the virtual machine file size dramatically with this procedure.


Shots heard around the city

less than 1 minute read

Shotspotter is used in several major cities to help localize anomalous impulsive sounds.

Quote of the Day

less than 1 minute read

Quote from Aristotle on how to realize the Earth is a sphere, in ancient times.

$100 VHF/UHF Wouxun UV3D walkie talkie

less than 1 minute read

The Wouxun dual-band 2m/220 and 2m/440 handheld radios are not perfect, but for half the price of comparable “big name” HTs are worthwhile.

ImageJ-Win64 won’t start

less than 1 minute read

If ImageJ won’t start on Windows, try the one-time command ImageJ-Win64 –cp jars/javac.jar and thereafter the ImageJ icon should work normally.


HP50g vs. TI-89

1 minute read

Comparison of graphing calculators HP 50g and TI-89.


Mathematics of Auroral Viewing

1 minute read

When you observe aurora borealis or aurora australis, what you see is a line integral of the optically thin aurora. Here’s the math.


Proposed HF TOA experiments

less than 1 minute read

A group is proposing experiments to determine limits on HF skywave direction finding. Let’s put the SDR-IQ to some experimental use!





Developing a radar for education

less than 1 minute read

with my first research internship upcoming, we will try to develop a radar on a cost scale practically never seen before.



Yaesu VX-7 Technical Review

3 minute read

Technical review of dual simultaneous receive, quad-band transmit and very compact size Yaesu VX-7.


Aftermath of Northeast power blackout

2 minute read

A few deaths, productivity losses and brownouts from Northeast power outages. No central coordinating standard being held up to compulsorily.



Nextel acquires 900 MHz SMR spectrum

2 minute read

Nextel spent a quarter billion buying 900 MHz Arch Wireless spectrum. FCC authorized 5 MHz more of 800 MHz for CMRS, when will it be our turn to be acquired?



CD-R is NOT for archival purposes

2 minute read

As CD-R writers become commoditized, some people don’t realize CD-R have a short lifetime, and even standard CD’s don’t live forever.


Wireless WAN in the Midwest

2 minute read

Wireless data or wireless WAN (WWAN) is growing rapidly. Going beyond two-way paging and package tracking to email for business.




Galaxy Saturn Turbo for 10m

2 minute read

How to use CB “export” gear legally for 10m amateur radio. This example is for the Galaxy Saturn Turbo.