Wednesday, 16 May 2012
Ultra-cheap VHF-UHF Software Defined Radio
Over the last few months various forums and websites I visit have been buzzing with conversations about the RTL-SDR project (e.g Hackaday)
The idea is to take a cheap USB FM/DAB/DTV receiver (for less than £20) that contains a Realtek RTL2832U chipset and an appropriate tuner chip (such as the Elonics E4000) then by using new custom drivers you get yourself a SDR-Radio with a frequency range of around 64 – 1700 MHz
Sound familiar? Yes it is similar to the FUNCube Dongle.
There are a couple of limitations, unlike the FCD the device doesn't have a pre-amplifier so sensitivity might be limited. The IQ sampling is only in 8 bits so the dynamic range will be limited, but because the device doesn't use a USB Soundcard interface like the FCD to pass the IQ samples to the PC the sample rate can be much higher (theoretically 3.2 MS/s) which allows potential decoding of wideband signals which the FCD cannot do.
Over the last few week I have seen a few Youtube videos and read of peoples experiments so my curiosity was piqued and decided to get one to have a go.
There in lies the problem, since news of this hit the internet demand for suitable devices has rocketed and dealers are cashing in and prices have risen and stocks are low. Also as not every USB FM/DAB/DTV receiver has a suitable chipset it is very easy to buy one that won't actually work. There is a list of known working devices here and yesterday while browsing ebay I found a dealer claiming to be selling the Newsky TV28T for around £16 including postage so thought what the hell!
Should be arriving in the next few days so I will keep you posted!
Before I go I should point out that on some forums and discussion groups I visit that some are under the illusion that they are getting a high quality wide band receiver for peanuts and then have complained because they have got a unsupported device or don't understand how the software works. I am under no illusions it will undoubtedly be fiddly, unreliable and inaccurate but it should be FUN!
If nothing else I will have a way of listening to DAB and watching DTV on my PC, which is hopefully better than my last purchase (which I should really dig out and check what chipset it has!)