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Registered Member #103
Joined: Thu Feb 09 2006, 08:16PM
Location: Derby, UK
Posts: 845
This is fantastic, and quite addictive! It reminded me of the time when I first got onto the internet in ~1999 and sat there amazed at how much is out there. I'll be spending a lot of time on this
The amount of band it covers in one go is incredible, but I can understand how it's possible to receive in software. What amazes me the most is the idea of creating an antenna that can have a flat response over that much band!
It turns the idea of radio being based on 'resonance' on it's head, as this is non-resonant reception! It shows how resonance is only a means by which we can achieve selectivity, from an engineering standpoint. A good analogy would be human hearing - it can receive sound waves over a relatively large band, all at once, but the processing is done entirely in 'software'. Disclaimer: I've had a bit too much wine, a recipe required some wine and that meant I had to open a bottle!
I was thinking of a simple project that could be based on this. A (fast!) comparator working as a one-bit ADC with a very high sample rate (100+Mhz) could receive the AM broadcast band, and processing in a mid-range microcontroller could provide the 'tuning' and demodulation, with the help of some fast external logic. Not sure if I'm missing something obvious here... it could be fun to try.
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
It's a good way of testing a new antenna, investigating propagation conditions, and so on - as you can transmit and look at the signal strength received in Holland at the same time.
I'm not sure I'd want to trade it in for one of my ancient analogue receivers though - why, I actually expect that a good CW beat note should rise and fall like a flute and need retuning every few minutes, living fossil that I am!
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Wide-band webSDR (Shortwave Digital Receiver) with antenna in Netherlands
