A quick recap – RTL2832U based TV tuners are great for software defined radio work. They’re inexpensive, and can be used to receive and demodulate a fair number of different signals. I’ve even written a few articles about what they can do.
At the present moment, it seems Rafael Micro R820T front-ends are the preferred sort since Elonics went bust – and there’s two main types of R820T based tuners out there. There’s the mini sort which I looked at here, and there’s this – a full size one which resembles the old full size Elonics ones.
The package looks like this. You can almost see everything already from the outside – interesting it says Digital Energy. That just sounds funny. Anyway – there are three main advantages to the full size tuner:
- It’s cheaper. By about 10%, or $1.
- The remote actually has a CR2025 battery in it which you can re-use for something else – the mini one makes do with two AG10’s instead (a bit of a rort).
- It’s got a proper USB connector. The mini one uses gold fingers on the PCB inside the shroud as the connector pins, this means that any movement will cause the tuner to drop out. This is much less likely with this full-size tuner.
The disadvantage of the full size tuner is that it’s bigger. In fact, it’s a bit thick – so it obstructs your ability to use adjacent USB ports effectively.
There’s the rear of the package.
This tuner comes with an interesting burnt CD-R driver CD that contains a copy of BlazeVideo. It’s not a great PVR solution, but it’s not the same as the one provided with the mini-stick either. It’s not really important – with BDA drivers, you can use any tuning software you please, and for SDR work, it’s all irrelevant.
The tuner stick itself has a hole for the LED in the bottom right hand corner, and slotted vent holes that expose the IR receiver in the top left. A cap is provided, unlike that of the mini stick, but it’s easily lost.
Just like most of the tuner sticks, this one has a MCX connector for the antenna. You can grab MCX to F-adapters for some fun, or just chop off the MCX cable from the crappy antenna base and use that with a connector to build your own adapter.
The rear seems to show it is FCC certified, CE certified and is not to be disposed in household rubbish for EU regulations. Uh, I’m not so sure about that, but it’s not exactly that important either.
Inside, we see a few electrolytic caps which might be helpful for power filtering which the mini stick could not accomodate in its size. There is a full size through-hole crystal as well, although it seems that in usage, the mini stick has a much better frequency accuracy requiring virtually no adjustment, whereas the full size stick is about 50ppm. There’s the Rafael Micro R820T tuner we’ve been promised as well, a linear regulator, an EEPROM with the vendor information on it and the IR receiver and LED. The mini stick does not have an LED.
As a bit of a modification, I almost always snap off the IR receiver and LED. I’m not interested in remote control operation and I really just want to save current. This could mean the difference between operation and non-operation at the end of really long USB extensions.
The rear of the stick shows nothing special. Just the through hole mounts for the USB connector, MCX connector, electrolytic capacitors, LED, IR receiver and crystal.
In use, it seems that both stick are comparably sensitive. I could not tell just from looking at ADSB plots whether one stick was better than the other. Furthermore, when working with the same antenna, radio reception of narrow band FM and wide FM seemed quite similar with both sticks.
The mini stick does get extremely hot after usage – unplugging it and touching the MCX connector can be quite painful!
So I suppose if size is not an issue, go for this one!