Globo 4



Power supply

  Flight 2(bis)
  Flight 3(bis)
  Flight 4
  Other 'ballooners'

Logo LU2HDX Club de Radioaficionados Lago San Roque


This fourth experiment is, mainly because of lack of time, a combination of old and new hardware. The beacon transmitter has shown to be reliable and was applied again. The transmitter antenna is the same with small modifications.

Larger differences are: instead of a 35 mm-camera, this payload uses a webcam, and transmits the images in SSTV (Slow Scan Television). This should have been the next step after a test in the Globo 3 experiment, but the test image generator on that flight failed. This payload will have an experimental receiver in the aeronautical bands, and will try to establish measurements using VOR signals of different airports.

Here's an index to the different areas of development. Parts were developed at the university by students of mine, as indicated in each module.


I'll gradually add the info as it becomes available. Please be patient...

Power Batteries Comparing the cells on the market, and having a few surprised while doin' it

Switching power supply The battery voltage will be transformed into standard +5V bus using a switching regulator
Beacon Transmitter The small (150 mW) beacon transmitter

Antenna Omnidirectional antennas do have a few secrets left
VOR Navigation VOR navigation

Simulation Simulating the received VOR signal to test the circuits and a few mp3 files with test signals.

Receiver Step-by-step contruction history

Antenna Lightweight horizontally polarized omnidirectional antennae are a project onto themselves.

Airports Listing of Argentinian airports and their nav aids

Sensors Sensors


Electronic compass Compass A last minute addition to the project: a 3D fluxgate magnetometer.

Principle How does it work (incomplete)

Cores tested Results from a few core materials tested

More materials a configurations More materials tested, and several test with silicon steel.

Circuit The final configuration selected, and the controller

Results Measurements, and calibration data
Camera Camera and circuits Camera, associated circuits, and experiences

weeCam Experiences with cheap parallel webcams - Alaris weeCam.

Generating audio How to generate precision audio with a low-cost microcontroller

Information on SSTV Norms, comparisons, and other info on Slow Scan Television.


(c) John Coppens ON6JC/LW3HAZ mail