Friday, May 31, 2013

Thursday, May 23, 2013

Pocket Android AM/CW/SSB Receiver for WebSDR

This is an Android only application used to remotely control several HAM radio sources:
- Ham Radio Deluxe (through the HP IP Server, CAT only, sound can be done through Skype or other IP phone);
- A FT8x7 transceiver connected through Bluetooth or USB cable (bi-directional CAT only, no sound);
- A SDR multiband server located in KN34bk (multi concurrent users SDR receiver for 80/40/30 and 20m bands.
Current features:
- Works on any Android device, including smartphones, tablets and Google TV, with a minimum resolution of 320x240 and Android version 2.1 or higher (3.1 or higher for USB support);
- Works in both portrait and landscape modes;
- tuning through the rotary knob or by directly entering the frequency from a numeric keypad (in MHz);
- Up/Down buttons to tune with a preset step which depends on the selected band;
- 16 presets (including frequency, mode, info. For each of the 16 memories all parameters are saved (freq, alias, description, band, mode, etc);
- ON/OFF button. When off, the application is disconnected from the server/transceiver;
- select band from the pool of available ones;
- select operation mode (AM/ LSB/USB/CW);
- display: SWR in both graphical and text mode;
- possibility to change application font size to match any device or taste. Font size is then stored in the config file and displayed on the startup screen at next run;
- a FN key to extend the number of memories to 16 and add future functionality to some buttons;
- 16 Memories to store frequency, mode and text info;
- work in both portrait and landscape modes;
- UTC clock included in the interface;

Tuesday, May 07, 2013

ESTcube: radio details

Technical Details: packet downlink

  • Frequency: 437.505 MHz
  • Frequency deviation: 3.5 kHz
  • Modulation: 2FSK
  • Output power: 0.5 W
  • Bitrate: 9600 bps
  • Callsign: ES5E-11
  • Packet format: AX.25 UI frames
  • Data payload per packet: up to 239 bytes
  • Active: during commisioning period - mainly over the Europe, later also periodically sending housekeeping data in bursts after every 3-4 minutes

Technical Details: CW beacon

  • Frequency: 437.250 MHz
  • Modulation: CW
  • Output power: 0.1 W
  • Bitrate: approximately 9 bps, 18 WPM
  • Callsign: ES5E/S
  • Sending period: 3 to 4 minutes
  • Sending format: mostly letter-coded HEX numbers (see conversion table below)

Groundstation requirements

While CW beacon can be received with very simple setup (even small handheld yagi will do) and either CW-capable transceiver or SDR receiver, for packet downlink requirements are more serious. Example minimal setup to receive successfully ESTCube-1 is given as following:
  • Yagi antenna with gain more than 16 dBi, preferably a crossyagi
  • Low noise preamplifier for 70cm band
  • Antenna rotator for both azimuth and elevation
  • Transceiver capable to receive 9600 bps packet
  • G3RUH-type TNC (e.g. Kantronics KPC-9216+) or SDR with appropriate software (e.g. based on
  • Packet data could be received also using a soundmodem program - AGWPE, MixW, Linux Soundmodem, MultimonNG etc

Orbit info

TLE-s will be available via NORAD:
Preliminary TLE-s for ESTCube-1 are following:
1 00000U 00000    13127.17171296  .00000000  00000-0  10000-3 0 00005
2 00000 098.1390 205.7730 0134000 220.5400 211.2631 14.71982716000009

How to send reports to

When sending received data to given e-mail address, please add following information
  • Your name
  • Your callsign (if exists)
  • Skype contact (if desired)
  • Location in geographical coordinates or WWL locator
  • Time of acquisition of signal (UTC) (day:hour:minute:second)
  • Time of loss of signal (UTC) (day:hour:minute:second)
  • CW data as an ASCII string (if recieved)
  • Packet data as binary attachment or decoded AX.25 packets in ASCII HEX (if recieved)

Interesting and useful for us would be also additional information such as:
  • Short description of equipment
  • Signal to noise ratio interval (min-max dB) or
  • Signal strength interval (min-max S level)
  • Qualitative description of radio link (tumbling? abrupt losses?)
  • Other comments