SDR Newbee looking for help / advise

[gunter breite]

Hi there,

it is now several month that I am trying to get an SDR working.

I started with a cheap Wish Starter Pack which never worked and went into the trash.

I went for an original RTL-SDR (which is also MIC ?) and could not get it to work either (tested on WIN-XP, WIN-7, Raspberry-Buster, Linux-Lite with GQRX + gnuradio, cubicsdr, sdr-sharp). Presuming a malfunction the dongle was returned ....

I am now with a nooelec nesdr-smart which is connected to a powered hub on a Pi 3B+ (Buster).

The device is recognized as (lsusb):

Bus 001 Device 005: ID 0bda:2838 Realtek Semiconductor Corp. RTL2838 DVB-T

I managed to install Gnuradio and GQRX 2.11.5. It is starting but I fail to receive anything. All I get is white background crackling noise and a fully yellow waterfall.

The antenna connected is the telescopic one which came with device, I am trying to receive a local FM Station at 101.3 MHz

An ordinary FM-Radio sitting next to the nooelec-nesdr-smart is receiving this station.

Since this may well have been topic of an earlier post, I'd be happy to be pointed into that direction (or receive any advise & hints otherwise).

On my own I am running out of ideas for what else to check ....

best Regards

Gunter

[Simon Kennedy]

Hi Gunter,

Start by turning the gain down a lot, and experimenting with levels of gain. More gain is not necessarily better.

You can also try running gqrx from the command line and seeing if there are any error messages.

I would also try plugging it directly into the Pi.

Simon.

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[David Ranch]

It should also be noted that the included antennas with these little SDRs are *terrible*.  Yes, they will work but since you're probably running this all inside your home, they will be receiving (aka getting overloaded) with huge amounts of interference from near by computers, appliances, etc.  As such, you will probably only be able to receive the strongest broadcast FM and AM stations.  Start by trying to receive your favorite broadcast stations but if you really want to realize the full potential of your SDR and to listen to many other signals, you'll need a much better antenna at the top of your dwelling.  You can either have the SDR connected to this better antenna it right there at the roof and bring back the data via a long USB "repeater" cable (weather enclosures, etc required) or you need to connect the new antenna all the way back to the SDR via low loss coax.  This GQRX group can offer you many options to perfect your setup but since you're new and just getting started, don't over do it just yet.   One idea for now would be to connect your new SDR to a laptop and go outside.  Get away from buildings, power lines, etc if possible, put that cheap-o antenna on a cookie sheet (RF ground) and they play around.  That will give you a glimpse of what is possible.

--David

KI6ZHD

[righthal...@gmail.com]

My pi-4, Gqrx will manage just barely 6 MSPS. If you ratio the speed difference to the PI3, one gets a slower speed. What speeds have you tried ? What messages are you seeing in the console window ? Message like the following indicate a problem -

New FFT rate: 25 Hz

New FFT rate: 25 Hz

portaudio_sink::work(): Error writing to audio device: Output underflowed

portaudio_sink::work(): Error writing to audio device: Output underflowed

On Friday, November 13, 2020 at 7:24:39 AM UTC-8 simonh...@gmail.com wrote: