Ciao a tutti,
vi segnalo questo interessante link:
http://websdr.ewi.utwente.nl:8901/
dove e' possibile utilizzare "online" un ricevitore SDR per le bande 40 e 80 metri. E' un progetto dell'universita' olandese di Twente curato da PA3FWM
73 de IW0HK Andrea
p.s. queste sono le specifiche tecniche:
Hardware
The present system consists of the following hardware:
* A W3DZZ trap-dipole for the 80 and 40 meter amateur radio bands, on top of the 40 m high "Hogekamp" building of the University of Twente.
* Simple bandpass filters for the 40 m and 80 m bands.
* A quadrature mixer in which the signals are mixed with about 7080.7 kHz. This mixer is a Quadrature Sampling Detector or "Tayloe mixer", the well-known circuit with a four-position CMOS switch, which is also used in many amateur radio SDR front-ends such as the SDR-1000 and the SoftRock.
* Another such mixer operating at 3600 kHz.
* A PC with soundcards to receive and process the signals coming out of the quadrature mixers. The PC is an old Pentium-III at 1 GHz, running Linux and the WebSDR server software.
Software
The system consists of the following software:
* The WebSDR server software running on the server PC.
This software on the one hand does the digital signal processing to produce the audio data streams and the waterfall pictures, and on the other hand is a simple web server to offer this data and some static files to the users.
* A small Java applet running in the user's web browser, to send the audio data received from the server to the user's sound card.
* Another Java applet running in the user's web browser, which fetches the data for the waterfall display from the server and displays it.
* Some Javascript code on the web page, to "glue" things together.
