Tech / Special Interest → Ham Radio > Sub $20 SDR Receiver

Sub $20 SDR Receiver

Has anyone played with one of these RTL DVB-T dongles with SDR software? I got one for about $14, and although the image rejection and selectivity leave something to be desired, it's pretty cool for what it cost...

(cell phone pic, sorry)

Funny you should ask, I just started playing with a pair of them this holiday weekend. Since I read contradicting information about which tuner to prefer (E4000 or R820T, both are paired with the RTL2832U chip) and because of the low cost I simply got one of each.

In order to be able to receive HF ham radio as well I also bought an upconverter (which cost more then the two SDR dongles together , so much for a cheap hobby!).

Both dongles came with an antenna but the reception is pretty poor with those (unless all you want to receive is the local FM station). Lacking proper adapters (PAL in one case and MCX in the other) I resorted to using a short piece of wire and got immediately rewarded with a much better reception.

What software did you use ? I installed gqrx on Linux (openSuSE 12.1) and it doesn't look very different from your picture.
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Here's another:

»sdrsharp.com/

I've got one from "nooelec" on eBay, and a Fun Cube Dongle.

The eBay one is pretty amazing for $20. I run sdr# on Windoze, and Linrad on my Linux box.

The Fun Cube Dongle has much better selectivity, but it cost $150!
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SDRSharp under windows on my laptop is what I was using when I took that picture... I'm going to be installing gnuradio on one of my Ubuntu boxes later this week and playing with it there...
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A friend of mine tried SDR# on Linux today. I only saw it briefly but was impressed by the automatic decoding of the RBDS information.

I think I'll give Linrad a try as well.
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Yes. I am currently listening to an E4000 tuned to 103.1MHz here at the office while an R820T here is connected to a computer running ADSB# and tracking flights coming in to JFK along the south shore of Long Island. I am planning to implement ship tracking via AIS next. They are all running on Windows but I have gotten the dongles to work on my Mac running Mountain Lion.

I already have two E4000 based and three R820T dongles. Planning to order three more R820T's as I am finding more uses for them. Comparing the two, I have found the R820T to be better in terms of frequency coverage and sensitivity. While the E4000 covers 56MHz to 2200MHz with a gap, I find the R820T's continuous coverage from 24MHz to 1766MHz to be much more useful. About the only thing I have not been able to do with the R820T is run the kalibrate software against GSM signals on 1900MHz (which the E4000 will do).

Frankly, these devices are great and I wish they were available several years ago!
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I have an 820T dongle paired with sdrharp and an 820T used with sbsplotter and rtl 1090 for adsb.
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Can ou post a link to where you are buying the dongles?

eBay

»www.nooelec.com/store/

I have one of the NooElec TV28T v2 DVB-T USB Stick (R820T) and find the sensitivity to be rather poor. It has a hard time receiving local commercial FM broadcasts above the noise-floor, even with an 18 inch whip antenna.

I have had it replaced by NooElec and the replacement is just as poor as the original.
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Way more fun than laying out big bucks for a all-band radio...
Did notice one thing though...outside antennas are a must have. Even a small amount of building material can create a sort of faraday cage effectively blocking out some of the less powerful transmitters.
Also there's a good possibility that the receiver will pick up a lot of electrical noise from the computer that it's tied to, being real close and all that.
I did a end run around -that- trouble by locating an extended USB cable. This cable is 30+ feet and effectively locates the usb stick receiver way far away and out beyond the EMF field from the computer.
As far as antennas go, best cheap bet is just a long wire.
Old-timer HAM operators used to call it a field day dipole. Not supposed to be permanent install, you'd wind it up at the end of the day.
40-50 feet of plain copper 18AWG will do very well for both daytime and nightime use. Run it between two trees, or lay it on the ground, just keep it away from other metal objects.

Get the nooelec ones. On their site they have a link to their ebay store and thats the cheapest way to get thiers. Their sticks have esd protection on the antenna port which will solve the greatest killer of these being static from an antenna blowing out the front end of the receiver.

I got mine a few days ago but I can't seem to come up with the correct Google phrase to find out how to make it work with SDR# or SDR Console.
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Attention: one thing the SDR software does is create a new "socket" for the USB stick. Physically, the USB port doesn't change but instead, it will not recognize any other USB tuners. (I've got two, an ATI All in wonder HDTV stick and a noname TV stick)
Normally this isn't a problem, but you might want to try running this setup in a sandbox if you have other dedicated tuners that are already installed and working before installing this one....

can you tell me what the sensitivity and selectivity of both models is and if it is user selectable ?
is there a discriminator output on any of these ? (probably can be modified for that with difficulty)
there are no specifications for the 3 devices on nooelec.com
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There's no discriminator output because there's no discriminator.

The stick sends I/Q data to the PC where the software works its magic.

Anything that you'd use a discriminator tap for would be done in software.

Whether that software exists is another matter.....
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thanks.
i should have assumed the radio output would be digital (need more coffee lol)

thanks for the info.
ill go ahead and get both units to toy around with.