Thursday, 19 July 2018

How to fix shared folder permissions in VirtualBox

For my SDR experiments, I installed Skywave Linux in a VirtualBox VM. To transfer IQ files, I needed a shared folder between the Linux guest and the windows host.
Skywave Linux running in VirtualBox
Long story short: To allow the user "andy" (in this case) access to the shared folder, he needs to be in the "vboxsf" group. To add that user to this group:

sudo usermod -G vboxsf -a andy

Works a treat.

Friday, 15 June 2018

How to get rid of the canberra-gtk-module error

Canberrra GTK missing

This is more like a "note to self":

The Problem:

I'm running Ubuntu 18.04 in an Oracle Virtual Box for radio experiments with the FL2k VGA adapter.
Gnuradio complained about a missing canberra-gtk module in startup. But I already had the canberra-gtk3 module installed.

The Solution:

It admittedly is a bit of a shotgun solution. I simply did a:

sudo apt-get install libcanberra-gt*

and that was that.

Friday, 8 June 2018

How to receive pictures from the international space station ISS

Spacecom the easy way

Certainly the easiest way to get started with space communications is to listen to transmissions from the ISS' amateur radio station. Actually it is easier than setting up a satellite dish for TV reception.
SSTV Picture received from the ISS


There are three kinds of transmissions that are easy to listen to:

  • Voice contacts, usually with schools. You will probably only hear the ISS, not the school, as the ground station will be out of your range and not use the downlink frequency.
  • Packet Radio / APRS. Needs noise-free reception to get anything at all
  • SSTV - Slow scan television. The word television might mislead the uninitiated. SSTV looks and feels more like colour fax.
All of the above are transmitted in FM. This allows very cheap equipment to be used for reception.


A directional antenna would greatly improve the signal quality. My 4-element Yagi is currently stowed away in the garage (and has been for the last 10 years).


Simple SSTV setup
Settings for the Baofeng UV-5R:

  • The frequency to tune to is 145.800MHz
  • Set deviation (Option 5) "WN" to 5KHz, i.e. WIDE
  • Set squelch (Opion 0) "SQL" to 0, i.e. always open
  • Set to comfortable listening volume
Settings for the App:

  • Mode is PD120 (although PD180 has been used in the past)
  • Disable "Auto Mode" (see above)
  • Enable "Auto Start" (although it will sometimes be triggered by noise)
  • Enable "Save to Photos"
Out of phase - can be corrected in the App

When to listen?

  • There are several web sites and twitter users constantly sending updates when interesting stuff happens. Specifically for SSTV, I recommend the ARISS SSTV Blog.
  • The next thing you need to know is if/when the ISS passes over your location. The ISS Tracker Website can help there, so can the free GoISSWatch App for iOS.

Other options:

I tried receiving the space station with a SDR-RTL DVB-T USB dongle. This is fine for local ham radio repeaters, but  with the very poor antenna that came with it, the ISS barely left a trace in the spectrum.
A Sdrplay RSP2pro should arrive any day now with the mail. I'll see how that compares.

Received 2018-06-07

Legal Caveats:

In some countries, even owning ham radio equipment without an amateur radio license is illegal. Transmitting without the proper permit and knowledge of frequency assignments is not only illegal, but also extremely stupid. Get yourself a ham-license if you want to do that. It is worth the effort.

Friday, 6 April 2018

Resetting an Avaya Conference Phone 1692

Resetting the Avaya / Polycom 1692

The correct reset code for FW 1.4

To get it on the new phone system, I needed to reset an Avaya 1692 to it's default configuration. There are several versions in the manuals. None of them seemed right for the firmware our 1692 was running. What worked for me was:
  1. Hit the "Mute Microphone" key
  2. Type 2723825327# (= craftclear#)
  3. Then confirm the clearing-request in the dialog

craftreset# will only restart the phone.
Avaya 1692
End of the story:
The 1692 is not compatible with the new IPOffice pbx. 

Thursday, 8 February 2018

The all-you-can-possibly-want ESP8266 dev board

All-in-one ESP8266 module

I did a very simple 5-minute example project with this board. The video will be available shortly.
The video is available here now!


The somewhat unwieldly name "Wemos® D1 Esp-Wroom-02 Motherboard ESP8266 Mini-WiFi NodeMCU Module ESP 8266+18650 Battery+0.96 OLED" betrays a very complete ESP8266 development module, that boasts a load of features:
  • USB2Serial bridge (Silicon Labs CP210x USB to UART Bridge)
    If your PC does not automatically detect the driver, you find it here.
  • Power switch
  • LiIon charge circuit
  • 18650 battery holder
    Beware: the holder is too short for my favourite protected 18650 cells. These INR cells should fit instead.
  • "Wemos" labelled ESP-12F ESP8266 module. It does not look like a WROOM-02, though.
  • SSD1306 OLED display
  • 4-way + push "joystick"

Bells and whistles
The Wemos product page does not list a module like that, so it might not be their product at all.
The advertised product name:
Wemos D1 Esp-Wroom-02 Motherboard ESP8266 Mini-WiFi NodeMCU Module ESP 8266+18650 Battery+0.96 OLED does not really fit in quite a few respects.
Leave a note in the comments, if you know more about that.

OLED details

The OLD display is white-ish in colour. It works with the usual SSD1306 library. The protocol is I2C.

No surprises here.

The PIN assignment is:
  • SDA=GPIO 5
  • SCL=GPIO 4 
The I2C Address ist 0x3c, as it is common for these modules.

4-way switch

To interact with the module, this is super handy.
The Pin assignment is:
  • UP = GPIO 12  (=D6)
  • DOWN = GPIO 13 (=D7)
  • LEFT = GPIO 0 (=D3, FLASH)
  • RIGHT = RESET (!)
  • SELECT = GPIO 14 (=D5)
The RIGHT pin is a bit of a questionable choice. Then again the module does not have a dedicated reset button.


I could not get the module to power up without a battery inserted.
People have reported that some components heat up when charging the batteries. I haven't noticed that yet.

IDE selection

I use the Arduino IDE on Windows whenever possible and the bare bones Espressif build environment on Linux whenever necessary.
  • Set-up of the Arduino IDE for ESP8266 ist >>here<<
  • For the Linux build environment, see >>here<<
In the Arduino IDE, I used "WeMos D1" as board type. and 4M (3M SPIFFS) for this module and did not have any issues with it.

Saturday, 6 January 2018

How to use a TTGO ESP32 module with OLED display and 18650 battery holder

TTGO ESP32 dev module

I got this very complete dev module from Banggood for review.

TTGO ESP32 Development Module


  • ESP-WROOM-32 Module
    (=Wifi, Bluetooth, two cores)
  • USB to serial bridge with Silicon Labs CP210X Chip
    (supported by Windows and Linux)
  • Charge Circuit for an 18650 battery (backside of board)
  • OLED display (SSD1306 or compatible) I2C version
  • LED on GPIO16
  • power switch

Notes from my experiments:


It was no problem getting the module to work with both the Arduino IDE and a generic ESP-32 developmnent environment (as provided by Espressif).
I set up a dedicated virtual machine running Ununtu with VirtualBox under Windows 10.
For the setup I simply followed the instructions provided by Espressif.


Unlike on other ESP32 boards with OLEDs, the OLED's I2C SDA and SCL pins are connected as follows:

SCL - Pin 4
SDA - Pin 5

It does not require an "enable" signal on GPIO16 as suggested in some programs I found. So comment these out if you see them.

Power requirements

When I didn't have a battery inserted, my powered USB hub apparently could not provide enough power when I activated WiFi and the ESP32's brownout detection triggered.
I haven't investigated that further. Either my USB hub dies not provide enough power, or the board's regulator is too weak to handle the current.

Example Project: Web Radio

As my first project, I ran a very simple web radio firmware on the module. The code was easy to find here on Github. A six minute video of my 5-minute project is available on my Youtube channel here.

Friday, 5 January 2018

Firefox FF Protecter malware plugin

FF Protecter [sic!]

Wahrscheinlich jeder, der sich "mit Computern auskennt", hat eine nette alte Dame deren Bitte doch mal nach ihrem PC zu schauen er nicht abschlagen kann.


Allein die Tatsache, dass ich aus dem Hilferuf der Dame nicht schlau wurde, legte nahe, dass irgend eine Form von Scareware am Start war. Unmöglich das am Telefon vernünftig zu qualifizieren.
Also Kinder ins Bett gebracht und ins Auto gestiegen.


Schon der erste Eindruck war deutlich: Firefox hatte sich über den gesamten Bildschirm gelegt und allerhand obskure Warnfenster in etwas unbeholfenem Deutsch aufgeworfen:

Sehr hässlich!
Keines der Fenster konnte mehr geschlossen werden. Der Task-Manager zeigte keine verdächtigen Prozesse, der Firefox Prozess konnte über den Task-Manager beendet werden. Damit war der Spuk vorbei.
Ich checke in solchen Fällen zuerst mit Autoruns, ob Programme im Kontext des Benutzers gestartet werden. Administrative Rechte hat die Dame nicht.
Das ist auch gut so, denn im "Downloads" Ordner lagen einige suspekte Installer für "Recovery" Programme. Hätte die Installation geklappt, wäre die Situation unangenehmer geworden.


Firefox startete nun zunächst wieder unauffällig. Aber nicht für lange: Nach wenigen Klicks poppte über eigentlich unverdächtigen Websites Werbung für Potenzpillen auf. Ein Indiz, dass die Ursache des Problems im Dunstkreis des Firefox liegt. Also mal einen Blick in die Plugins werfen...
Ooops... die installierten Plugins lassen sich nicht anzeigen. Offensichtlich schützt sich da ein Stück Schadsoftware selbst.

Safe mode

Also den Firefox mit gedrückter "Shift" Taste gestartet, schon war der Plugin Manager wieder zugänglich.

FF Protecter

Zwei Einträge passten vom Datum her sehr schön zum Beginn der Probleme. Beide Plugins nannten sich "FF Protecter" [sic!]. Nach deren Deinstallation gab es keine Auffälligkeiten mehr.

Eine Suche bei Google nach "FF Protecter" ergab keine Treffer. Die Suche nach der angeblichen Microsoft Support Nummer 08938034150 hingegen ergab, dass seit Ende Dezember 2017 mit Scare-Popups zum Anrufen bewegt werden sollen.
Was bei so einem Anruf passiert habe ich hier beschrieben.