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Distribution: Debian Sid AMD64, Raspbian Wheezy, various VMs
Posts: 7,680
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There's an antenna with the USB stick -- it's not much but it seems better than the ones I've had with standard FM radios. The station's an FM stereo (as far as I know but I tried all the settings) in case I missed it going off air or something I just verified that the station is still broadcasting, very clearly, on that frequency. I will have to search for a piece of wire -- sadly I'm not a true geek so don't have some immediately to hand and will likely have to cut something up and strip the wires.
I do know that you mean about the antenna but considering the radio I used to confirm the existence of the local station uses a wire about the same length as the wire to the antenna of the device unless there's something odd going on I think I ought to at least hear something that isn't static.
Distribution: Debian Sid AMD64, Raspbian Wheezy, various VMs
Posts: 7,680
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Quote:
Originally Posted by derive
Ohh, if you have the standard wide-band antenna shipped with the dongle it should be enough!
Well, yes, unless it's broken.
I think the next step is to buy another dongle.
I never could "get" what the SWR meter was telling me when I had a CB as a kid though so I am not good at RF.
A thought occurs: Can one Van Eck phreak using a SDR? Ok, getting well ahead of myself there.
True, it can be broken...
I use home made antennas, but the shipped should be far enough for receiving, just a little bit noisy for me...
In gqrx you should see yellowish areas while tuning even if there is nothing but noise.
I heard that many dongles doesn't have static protection, so it can be bad from the static electricity of the anntennas: https://ncrmnt.org/wp/2012/06/30/rtl...ic-protection/
That's better than a CB, you can broke that easily if you switch to transmit with a bad swr
( if swr is bad, the signal you sent out on the antenna wire reflexed back from the antenna, so your transmitter transistor gets back the voltage and it burns out)
With rtl-sdr you can't transmit, so no problem;
I just bought / received a similar unit today. As a quick test I installed sdrsharp in windows just to see if I could get it to work. Looks like the easiest to setup and did not have any problems receiving a local FM broadcast station with the supplied antenna. The one thing to note is make sure the gain setting is not set to zero or min. Not sure what the other programs use as a scale for gain. sdrsharp also has a wideband / narrowband FM settings. Broadcast radio should be wideband FM.
Will try with linux shortly...
Update: Still have not successfully got the SDR working on my Pi yet. I also have the PLL not locked message and like you all I hear is static....
Distribution: Debian Sid AMD64, Raspbian Wheezy, various VMs
Posts: 7,680
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A big thanks to all.
It seems the antenna is faulty. I tuned to my local FM station, unplugged the one shipped with the device, pushed the test probe from my multimeter into the socket and heard some quiet but distinct voices.
Now I need to work out whether I can repair the antenna or find something to cannibalise to get some wire to make one.
I'll mark the thread solved as the tools seem to install and work straight from the Sid repositories.
I would be interested to hear anyone's ideas of things to play with though and I'll post if/when I get my antenna situation sorted out.
Distribution: Debian Sid AMD64, Raspbian Wheezy, various VMs
Posts: 7,680
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I give up. I have a new device and a new antenna and now I cannot even reproduce the half-heard local station with either device using the new (admittedly bad) antenna nor the lead from the multimeter I was using.
I may try to compile some newer software and try it but it seems SDR doesn't work without a lot of effort and, even then, may not.
Distribution: Debian Sid AMD64, Raspbian Wheezy, various VMs
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So, I managed to stop throwing my toys out of the pram and decided to try to compile things and see whether that worked. I compiled gnuradio, gr-osmosdr and rtl-sdr from the git repositories and, using the following command from here, I managed to listen to a radio station very clearly:
Code:
http://sdr.osmocom.org/trac/wiki/rtl-sdr
So, it seems that the key to this is not using the repository versions of software but spending some time learning how to install from source. Yet another Linux hobby which takes a little longer than one would hope to get into but means learning some useful things.
I won't mark this as solved for a while and may either try to make a more details explanation of what I did when I set things up on my desktop or expand it to include anything else I manage to do.
Distribution: Debian Sid AMD64, Raspbian Wheezy, various VMs
Posts: 7,680
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I still can't get gqrx-sdr working -- but rtl_fm works fine. I finally received an adaptor today which allows me to use a decent antenna (well, better than the one shipped with the device) and now the local FM station is picked up very well and rtl_fm lets me listen to the local airport.
So, what I have learned so far is that gqrx-sdr is buggy and the antennas shipped with the cheap USB SDR devices are useless. This means that SDR on Linux is harder than it should be but perfectly doable.
Distribution: Debian Sid AMD64, Raspbian Wheezy, various VMs
Posts: 7,680
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I remembered to day that I have an empty socket attached to a TV/Radio roof antenna and a cable that will attach it to the SDR. I actually managed to get gqrx to play the local FM station but it's very noisy and faint whereas the following is spot-on:
I can also listen in on the local airport by modifying it and things are as clear as I'd expect from this location.
So, I think that just installing everything from the repositories works just fine (though I've a feeling I've a bit of a mix currently installed) but I'll have to search for an alternative to gqrx and start looking into trying to find and decode other things like plane tracking.
Edit: Just played with Dump1090 and, oddly, got better results with the antenna that came with the device* than with the roof-space antenna that works better listening to stations. I now have a program that creates a Flight Radar 24 site on both my desktop and this laptop though so it's all good fun.
So, it seems (probably obvious to some) that the antenna makes a big difference also. This makes me worry I'll be spending a lot of time and a little money (antennae seem cheap enough) trying things out. Still, this seems a fun thing to do so I'm glad I looked into it. Now I just need to find an antenna that's good for ADS-B -- might be fun to then plug it into the Pi and have my own "Flight Radar".
*As I mentioned I bought another device+antenna set but I had pulled apart the antenna for the first device trying out some ideas. So, I now have two USB RTL-SDR devices, one supplied antenna, an adaptor to allow the connection of standard coaxial antennae, an FM Radio Indoor Dipole and an existing roof-space, amplified (need to check on the status of that) TV/Radio antenna.
This antenna works really well for me.
Thick copper wire from Maplins. Measure it, mark it bend it. Connect to the coax centre.
The "groundplane" is made of aluminium foil hot-glued to cardboard, and connects to the coax braid. I have about 10cm of coax before it plugs into my RTL2838.
Mounted in the attic space, I can track planes as far away as Portsmouth and Rotterdam from where I am in central London. Running dump1090, my RPi feeds the data to FR24
Distribution: Debian Sid AMD64, Raspbian Wheezy, various VMs
Posts: 7,680
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Just looking into watching digital TV using the one plugged into my desktop, dist-upgrading an Ubuntu VM as I type.
For the Raspberry Pi I see that there don't seem to be the same binaries on the repositories so looks like I'll have to compile on that -- luckily I now have some experience .
Thanks for the tips regarding the antenna -- due to location I probably don't get the best coverage but I think if I find a good way to cable an antenna I ought to do better than I am at present. I like how I have a mobile ADS-B station that I can try on holiday even though it's not that great at present.
Be warned: the modules used for DVB-TV will conflict with those needed for SDR. You can't have the TV modules loaded if you want to use SDR.
Blacklisting is needed!
Keep your antenna cable as short as possible, losses are very high at 1090MHz. I use a 5m USB extender cable to keep my SDR dongle close to the antenna, rather than run a long length of coax to the RPi.
Distribution: Debian Sid AMD64, Raspbian Wheezy, various VMs
Posts: 7,680
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Quote:
Originally Posted by tredegar
Be warned: the modules used for DVB-TV will conflict with those needed for SDR. You can't have the TV modules loaded if you want to use SDR.
Blacklisting is needed!
Keep your antenna cable as short as possible, losses are very high at 1090MHz. I use a 5m USB extender cable to keep my SDR dongle close to the antenna, rather than run a long length of coax to the RPi.
Seems DVB-TV is harder to do than it was in Ubuntu (though that may just be me googling the wrong things). Am trying out DVD-TV in a VM so I don't conflict with the currently installed software.
I may have to get hold of a few USB extender cables -- for some reason my USB SDR doesn't seem to work through my my USB3 hub.
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