Архив за 03.07.2019

Other SDR Devices • HackRF choppy audio and no FFT Signal for FM

I just got a HackRF One (real, not clone) and am following the tutorial on Great Scott Gadgets (https://greatscottgadgets.com/sdr/1/) but when i plot the FFT all i see is a peak wherever i put my center frequency and no other signal peaks.

[Image of FFT centered at 97.9MHz](https://imgur.com/a/9ChyUO8)

This peak is at any location i change the center frequency to so i think its just DC noise from the ADC going into the FFT

When I play the audio all i hear is choppiness and i get "aU" (audio Underrun) in GNU Radio

[Here is my GNU Radio FlowGraph](https://imgur.com/a/DF9U0xR)

I tried reducing the sample rate variable to 8M, 4M, and 2M but got no luck. I tried reducing the audio sample rate below 48kHz and also still have the same result.

On my Baofeng radio i can hear plenty of FM stations around but i can't see their spikes on the FFT. I don't understand why.

Is my computer not good enough to run the hackRF and GNU Radio? I'm running on Ubuntu install on an HDD, not a VM.

Intel® Core™ i7-2630QM Processor (6M Cache, 2.00 GHz)
Intel HM67 Chipset
12GB DDR3 1333MHz, DDR3
Nvidia GeForce GTX 560M

I really dont understand why i can't even see the FM signals

Here is the output of `hackrf_info`

hackrf_info version: unknown
lbhackrf version: unknown (0.5)
Found HackRF
Index: 0
Serial number: 000000000000000087c867dc2a1f3b5f
Board ID Number: 2 (HackRF One)
Firmware Version: 2018.01.1 (API:1.02)
Part ID Number: 0xa000cb3c 0x00624766

I'm using the ANT-500 antenna (https://greatscottgadgets.com/ant500/)

Statistics: Posted by Byte_Farmer — Wed Jul 03, 2019 11:08 pm

Remote SDR over Hosted Server?

I'm not sure if anyone has tried this or not but I'm trying to see if there is any way to use a hosted server (such as from digital ocean) to help distribute the bandwidth of a remote SDR.

The idea is similar to how shoutcast works, you run a small application on your local pc which sends SDR data to the hosted server, then clients connect to that hosted server which distributes the data that it pulled from your local machine.

In this way I could support hundreds of clients or more while only having a small 100-200kbps load on my local network.
I ask because I'm looking to stream an SDR that may require more bandwidth than is possible from my location.

I've been trying to think if there was a way to duplicate and hand out this data but have come up with nothing. I thought about tunneling over SSH and forwarding my local port to the server however... that's just going to lead all those client connections back to my local pc and won't help with bandwidth. Any thoughts?

submitted by /u/Corrosive_One
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A question about turnstile antennas and circular polarisation

A question about turnstile antennas and circular polarisation

I want to make a turnstile antenna and I calculated all the required measurements via this guide, but before I start building I want to know if everything is correct.

Today I went searching on how I adjust it for the RHCP signal from the NOAA and Meteor satellites, after reading wikipedia I discovered that I need to place it in 'axial mode', but I couldn't clearly understand what they mean by that. Do I need to hold the antenna at an angle, if yes, what angle? Or do I need to wire things differently? The images in wikipedia weren't clear enough.

I calculated these things:

Design made in paint

Also, the guide I used said that the reflector arm length is calculated with the wavelength and the driven element is 5% shorter. Is this correct? In my mind it would make sense if the driven element is calculated with the wavelength and the the reflector is 5% longer, but I'm new to antennas so I don't know if I'm correct.

I kinda want to do this right the first time as I can't waste a lot of money on rebuying everything.

Also tagging u/VA7EEX because he already made a turnstile antenna, but the thread is archived.

submitted by /u/melvin2204
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KerberosSDR • Re: Update rate not showing

I did comment it again, out of curiosity, and it still works. So I'm not sure why both work. I'll just leave it commented out since that's how it supposed to be. Not sure what went wrong. I followed the instructions thoroughly.

Statistics: Posted by stasia327 — Wed Jul 03, 2019 4:53 pm

Why are my images so dark?

Anyone have any tips? All my images look like this: https://imgur.com/a/4f8vMud

I'm using a V-dipole with a RTLSDR. No LNAs or filters, I'm just getting started and haven't bought any of that yet. I pipe the audio from SDR# to WxToImg with VB audio cable.

Do I need to find an area with less interference? I don't know what the problem is or how to go about getting a clearer image.

submitted by /u/ColTaylon
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Hello Hi guys I am searching Antenna To increase frequency range BladeRF Any site you recommend…

Hello Hi guys I am searching Antenna To increase frequency range BladeRF Any site you recommend buying from it

(Feed generated with FetchRSS)

Comment on SDRSharp Users Guide by ozzie.freddo

To the right of the frequency selector at the top there is a setting that gives three options that will solve your problem…they allow Centre Tuning, Free Tuning or Sticky Tuning. You seem to be on Centre Tuning.

KerberosSDR • Re: Update rate not showing

I'm positive.

I actually followed the instructions for the Debian PC on my Ubuntu VM so I cloned the software straight from GitHub.
It's working now just fine.
I'm getting an update rate, my spectrum displays are up, it syncs the tuners, etc.

Statistics: Posted by stasia327 — Wed Jul 03, 2019 11:48 am

Has anyone received MetOp-C LRPT yet?

MetOp-C has been activated today and according to WMO OSCAR it has an LRPT transmitter. Did anyone receive this yet? I'm going to try to receive it today at 10:20 UTC and try to decode it with the available decoders.

submitted by /u/melvin2204
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KerberosSDR • Re: Update rate not showing

stasia327 wrote:
Mon Jul 01, 2019 3:48 pm
So I have found a bug that's been causing all my suffering in hydra_receiver.py


Traceback (most recent call last):  File "/home/abourlas/kerberossdr/_signalProcessing/hydra_signal_processor.py", line 163, in run    self.module_receiver.download_iq_samples()  File "/home/abourlas/kerberossdr/_receiver/hydra_receiver.py", line 206, in download_iq_samples    return iq_samples    NameError: name 'iq_samples' is not defined

it should be


return self.iq_samples.
I noticed that this is commented out on the GitHub page; however, the version of software I have is straight from the newest image.
Hmmm but that line is meant to be commented out, and it's commented out in the premade images. Are you sure you didn't accidentally uncomment it at some point?

Does the program work normally now ?

Statistics: Posted by rtlsdrblog — Wed Jul 03, 2019 10:09 am

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