search

ha7ilm / openwebrx

Open source, multi-user SDR receiver software with a web interface
https://sdr.hu/openwebrx
GNU Affero General Public License v3.0
989 stars 476 forks source link

Poor reception? #45

Open ways opened 8 years ago

ways commented 8 years ago

Hi

I'm running this on a raspberry pi 2 (have also tried on 1) with raspbian and an rtl-sdr dongle. When running on my laptop with gqrx the dongle works fine, but when running on the pi with openwebrx I get the waterfall and noise, but no reception. Can't even hear local radio stations. Any idea why?

ha7ilm commented 8 years ago

Hi @ways!

Make sure that you are using the same gain setting (and sample rate) for OpenWebRX and Gqrx.

For OpenWebRX, the default setting is manual gain around 5 dB (rf_gain=5 in config_webrx.py). You can set it to auto gain by rf_gain=0.

The default sample rate is 250 ksps, which will allow you to see 250 kHz bandwidth on the waterfall diagram.

Best regards,

Andras

ways commented 8 years ago

Ok, rf_gain=0 got me some more noise in the graph instead of just white noise. But not much better. Limiting the bandwidth also did something, but still unusable.

ways commented 8 years ago

Is the dev branch better?

ha7ilm commented 8 years ago

No, the dev branch is outdated now.

ha7ilm commented 8 years ago

Maybe you could check what happens if you run rtl_tcp on the Pi, and connect to it via gqrx on the laptop. Does it have better performance (with the same settings) or the same as OpenWebRX?

ha7ilm commented 8 years ago

Also you could try to run OpenWebRX on the laptop and see if the results are different than running it on the Pi.

In theory, the algorithms behind OpenWebRX should not perform worse than other SDR software in terms of reception quality. I think it is more likely that some noise is introduced by the RPi power supply, or something.

leastonce commented 8 years ago

I run an airspy on a pi 3 and it's pretty decent at 2.5Mbps. The audio gets a bit choppy when changing frequency but it's no worse than gqrx on my Mac.

Sent from my iPhone

On 23 Aug 2016, at 20:24, András Retzler notifications@github.com wrote:

Also you could try to run OpenWebRX on the laptop and see if the results are different than running it on the Pi.

In theory, the algorithms behind OpenWebRX should not perform worse than other SDR software in terms of reception quality. I think it is more likely that some noise is introduced by the RPi power supply, or something.

— You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or mute the thread.

ways commented 8 years ago

I'll see if I can get hold of a Pi3. if not, I'll try it on a laptop.

Maribomba-Azure commented 7 years ago

I've got my Pi3 (Ubuntu Mate) and my RTL2832U & HackRF but both give a very weak (not hearable) signal, I've tweaked with the gain for both radio's but no success for even "loud" local repeater/broadcast signals. Tested with same results with full Ubuntu Desktop in virtual machine.

ha7ilm commented 7 years ago

Is the noise weak as well, or it only happens when you tune to a strong signal?

Maribomba-Azure commented 7 years ago

Spectrum is the same, doesn't matter where. Known strong signals are very tiny visible.

Maribomba-Azure commented 7 years ago

img_1685 This is the signal from my HackRF/PortaPack so with a gain of 40 on OpenWebRX I see the signal however I cannot have the correct modulation (which should be NFM/FM for this local repeater). It gives sound but nothing remote to voice?

ha7ilm commented 7 years ago

@Techinput Do you hear the noise if you tune to anywhere else?

Maribomba-Azure commented 7 years ago

I hear the normal noise and I hear the other "noise" for the station that I see