RTL-SDR (cheap software radio), fun and cool for the kids....

[ARCHIVED THREAD] - RTL-SDR (cheap software radio), fun and cool for the kids....

Posted: 10/23/2014 4:04:14 PM EDT

Might be the wrong forum, but didn't want to GD it up. Anyone using one of these $20 radio receivers?

Got one in the other day and have a very basic understanding of it. Using it to track aircraft via ADS-B signals using fairly automated and free software. The other night me and the 11 year old kid were in the garage using it, spotting aircraft using the software then going outside and spotting them in the sky to verify. I don't live near a large airport but seem to be in the flight path of most of the traffic going from TX/CO to Japan/Korea and CA to Europe. Kinda neat, but i want more use.

I've wandered around the spectrum and stumbled across some voice traffic (EMS and railroad), originally wanted to set it up as a police scanner but found the locals are P25 and possibly encrypted. The software to do that is fairly complicated and got discouraged (may just buy a dedicated scanner). At any rate, had fun with the kid and was a learning experience for both of us.

Posted: 10/23/2014 4:09:33 PM EDT

[#1]

Yeah they are pretty cool for the price.

NC VIPER system here is also in P25 but there is software that will decode it. If they are trunked you really need a separate dongle for the control freq and then another to listen to the other freq. Haven't messed with it in a while but UNITRUNKER for trunking and DSDplus for the P25.

Posted: 10/23/2014 7:06:20 PM EDT

[#2]

Got one earlier this week. Gotta get a few more for unitrunker. It's a great 2.4MHz bandwidth spectrum analyzer. I have found several conversations in the 2M band that I would have never heard otherwise. I need to get a scantenna for it.

Posted: 10/23/2014 7:53:35 PM EDT

[#3]

Yep, I have it hooked to an external discone. Lots of interesting signals out there.

Posted: 10/23/2014 10:40:55 PM EDT

[#4]

And in my measly wisdom, I can't get the freakin software to load,.....

Posted: 10/23/2014 11:04:21 PM EDT

[#5]

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And in my measly wisdom, I can't get the freakin software to load,.....

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Ha! Don't feel bad, I had it running last year on an old XP machine, and now I can't get it to work on a new Win 8.1 or a Linux computer!

Posted: 10/23/2014 11:13:06 PM EDT

[#6]

I have an APRS I-Gate setup using one, running on a Raspberry Pi. It's all in my attic.

The important thing with these dongles is to get the frequency offset correct, then keeping the crystal a uniform temperature (you can swap it out with a TXCO).

Posted: 10/24/2014 8:37:08 AM EDT

[#7]

I have one that I use for airplane tracking (I live under the local flight paths) and enjoy that.

I want to buy a second one and try to figure out the police scanner application.

Posted: 10/24/2014 10:09:20 AM EDT

[#8]

I have several that I bought last year. I am driving two of them right now with Raspberry Pi's; one at my home QTH on the north shore of Long Island and the other at my work QTH on the south shore of Long Island. They feed to an old laptop running Windows 8.1 with Virtual Radar Server 2.0.2. Gives me nice coverage of the metro-NYC area with the home QTH favoring the north and the work QTH favoring the south over the Atlantic ocean. One Raspberry is feeding FlightRadar24.com and both are feeding to FlightAware.com. The power draw is negligible that I leave them running all the time except to update the Raspian OS and modules. For antennas, I use home built 1/4 wave antennas tuned to 1080MHz by a neighbor that used to work at a shop with an RF analyzer. He was able to cut them to be resonant at that frequency.

Overall, they are great gadgets and the price is quite reasonable for what they do.

Posted: 10/24/2014 1:30:26 PM EDT

[#9]

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I have an APRS I-Gate setup using one, running on a Raspberry Pi. It's all in my attic.

The important thing with these dongles is to get the frequency offset correct, then keeping the crystal a uniform temperature (you can swap it out with a TXCO).

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I was doing this…but on a Ubuntu server.

I turned it off due to the instability…and am setting up a scanner based I-Gate off a Bearcat BC560XLT for all of the APRS frequencies it will read.

Posted: 10/24/2014 2:23:14 PM EDT

[#10]

Interesting! I was just coming in to the forum to see if anyone had any information about this and/or had set up something using these components. I ordered my parts today, and they should be here by the middle of next week. Tag for more info!

ETA: Starting out with a RPi (my first time using one, but I'm somewhat familiar with Linux) and the radio package. My initial thoughts were something like this:

Quoted:
I have one that I use for airplane tracking (I live under the local flight paths) and enjoy that.

I want to buy a second one and try to figure out the police scanner application.

View Quote

Posted: 10/24/2014 2:33:58 PM EDT

[#11]

I have had a hell of a time getting it to work on a Linux machine.

Posted: 10/24/2014 3:46:27 PM EDT

[#12]

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I have had a hell of a time getting it to work on a Linux machine.

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I can't get it to work reliably on a Pi (I did have working as a receiver on Svxlink for a bit)…however works just fine on other computers with Ubuntu and Arch running on it.

Posted: 10/24/2014 4:03:18 PM EDT

[#13]

Here are some links that I have found useful:

http://www.rtl-sdr.com/adsb-aircraft-radar-with-rtl-sdr/

https://sites.google.com/site/policescannerhowto/

http://www.rtl-sdr.com/rtl-sdr-tutorial-following-trunked-radio-unitrunker/

Posted: 10/25/2014 8:46:55 AM EDT

[#14]

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I can't get it to work reliably on a Pi (I did have working as a receiver on Svxlink for a bit)…however works just fine on other computers with Ubuntu and Arch running on it.

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I have had a hell of a time getting it to work on a Linux machine.

I can't get it to work reliably on a Pi (I did have working as a receiver on Svxlink for a bit)…however works just fine on other computers with Ubuntu and Arch running on it.

Sounds like you have a power issue with the Pi. The polyfuse limits the USB current. Either get yourself a powered USB hub, back feed through the USB ports or (what I plan to do) replace the polyfuse with a 1.6A variety (voids the warranty BTW). DUMP1090 kept freezing up or the Pi stopped communicating over the Ethernet and required rebooting. I am temporarily backfeeding one Pi and it has been running continuously 7 days without a hiccup. Definitely a polyfuse issue.

Posted: 10/25/2014 8:53:27 AM EDT

[#15]

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Sounds like you have a power issue with the Pi. The polyfuse limits the USB current. Either get yourself a powered USB hub, back feed through the USB ports or (what I plan to do) replace the polyfuse with a 1.6A variety (voids the warranty BTW). DUMP1090 kept freezing up or the Pi stopped communicating over the Ethernet and required rebooting. I am temporarily backfeeding one Pi and it has been running continuously 7 days without a hiccup. Definitely a polyfuse issue.

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Gen1 Model Bs had polyfuses on the USB outputs. Easy way to fix this is to go to get a powered hub. I had this issue with my Gen1.

The gen2 devices are a little better, but still have a polyfuse on the input port.

The B+ has an input polyfuse, but it's a little higher capacity, and mostly removes the issue, as long as the surge current is less than the polyfuse.

Posted: 10/25/2014 10:23:03 AM EDT

[#16]

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Quoted:

Gen1 Model Bs had polyfuses on the USB outputs. Easy way to fix this is to go to get a powered hub. I had this issue with my Gen1.

The gen2 devices are a little better, but still have a polyfuse on the input port.

The B+ has an input polyfuse, but it's a little higher capacity, and mostly removes the issue, as long as the surge current is less than the polyfuse.

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Quoted:

Sounds like you have a power issue with the Pi. The polyfuse limits the USB current. Either get yourself a powered USB hub, back feed through the USB ports or (what I plan to do) replace the polyfuse with a 1.6A variety (voids the warranty BTW). DUMP1090 kept freezing up or the Pi stopped communicating over the Ethernet and required rebooting. I am temporarily backfeeding one Pi and it has been running continuously 7 days without a hiccup. Definitely a polyfuse issue.

Gen1 Model Bs had polyfuses on the USB outputs. Easy way to fix this is to go to get a powered hub. I had this issue with my Gen1.

The gen2 devices are a little better, but still have a polyfuse on the input port.

The B+ has an input polyfuse, but it's a little higher capacity, and mostly removes the issue, as long as the surge current is less than the polyfuse.

I've got 1 Gen 1 B and 2 Gen 2 B's. So that could be the problem. The dongle itself is what I've had stability issues with. I'd buy one that's more stable…but $200 starts getting a little pricey.

Posted: 10/25/2014 11:20:26 AM EDT

[#17]

Just use a USB extension out of the hub to get it away from the RFI sources in the hub and Pi itself.

I've considered some kind of potting compound to stabilize the temperature, and help with RFI ingress a little bit.

Posted: 10/25/2014 10:06:42 PM EDT

[#18]

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Just use a USB extension out of the hub to get it away from the RFI sources in the hub and Pi itself.

I've considered some kind of potting compound to stabilize the temperature, and help with RFI ingress a little bit.

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Someone mounted their RTL dongle in a tin full of mineral oil…I can't remember who.

Posted: 10/25/2014 10:34:18 PM EDT

[#19]

Mines pretty stable after about 10mins. I use it as my spectrum scope for my 7600.

Posted: 10/27/2014 10:09:37 AM EDT

[#20]

Anyone want to throw up some screenshots, pics, specs, and/or capabilities, of their home made SDRs on regular computers or RPis? I would love to see what everyone is doing with them and how they're using them.

ETA: Or do we already have a thread that I'm missing?

Posted: 10/27/2014 10:23:02 AM EDT

[#21]

Supposedly there is software out there that will decode MotoTRBO. Has anyone played with it and does it work. My local SO is switching from analog VHF to MT VHF.

Posted: 10/27/2014 10:29:35 AM EDT

[#22]

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Supposedly there is software out there that will decode MotoTRBO. Has anyone played with it and does it work. My local SO is switching from analog VHF to MT VHF.

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DSDPlus.

http://wiki.radioreference.com/index.php/DSDPlus

Posted: 10/27/2014 10:35:10 AM EDT

[#23]

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Supposedly there is software out there that will decode MotoTRBO. Has anyone played with it and does it work. My local SO is switching from analog VHF to MT VHF.

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work is MotoTRBO and yep - you need a decent computer for it though (my "portable setup" - shitty old small dell laptop couldn't decode realtime)

Posted: 10/27/2014 4:02:49 PM EDT

[#24]

Thanks for the answers gents. I was hoping I could get the software working on a Pi so I could monitor to and from work but it sounds like the Pi might not have enough HP.

Posted: 10/27/2014 4:03:34 PM EDT

[#25]

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Quoted:

Anyone want to throw up some screenshots, pics, specs, and/or capabilities, of their home made SDRs on regular computers or RPis? I would love to see what everyone is doing with them and how they're using them.

ETA: Or do we already have a thread that I'm missing?

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Trackin' planes. I'm like a little kid in that I get a bigger kick out of this than I should.

That and decoding the P25 system here in town for police/fire/etc. I have also heard that that you can decode POCSAG pagers like hospitals commonly still use, but I'm not sure of the legality of that one