Архив за 26.05.2019

KerberosSDR • Re: Power connection question

have not observed any throttling. i will then propose the current meter i have is smoothing the readings. power source is a RAVPower 4-USB supply and has proved to be an improvement over the 'official' Raspi power supply. also using a short USB cable to the Raspi.

Statistics: Posted by kb3cs — Sun May 26, 2019 11:33 pm

Unusual signal seen on 13260.3 khz today. Any ideas as to what this may be?


This evening I was scanning through the HF spectrum, and I came across this signal, and I'd like some feedback on what this may be: http://www.cathalferris.com/files/sdr/13260khz_20190526_odd_signal.JPG

I'm a relative newbie to the world of SDR, so please do bear with me.

I'm located in one of the eastern suburbs of Limerick, no major industrial areas within 2km of the house. It appears to be a relatively low RFI area based on what I've seen so far.

I've got an RTL-SDR v3 dongle on a Raspberry Pi 3b+ (running current raspbian). On that Pi I'm running Airspy's spyserver to get the data to any of a few other devices on my home network.

For an antenna, I'm using about 7m of speaker cable, split into the two strands, and set up as a dipole at the side of the house. The ends of the cable are wound around the tips of the RTL-SDR antenna kit and extend away in a roughly NNE/SSW direction parallel to the ground. The centre conductor of the coax cable going to the dongle is attached to the northerly leg, if that's of any relevance

Using the v3 dongle in direct sampling mode has let me tune into a number of SW stations around the 9kHz and 12 kHz regions, and I can hear lots of Morse in the 20m band. So, I'm reasonably sure that this setup is working and valid. Plenty of noise and interference, but not too bad.

I changed the bandwidth in SDRConsole to ~21kHz get a better waterfall of this signal. I'm decoding this signal on a Dell core i5 laptop, and I'm able to see this signal in other SDR applications as well. SDRSharp also shows the same waterfall pattern, as do those applications running on another laptop.

Here's a 60 sec recording of the data for those that want to play along at home:http://www.cathalferris.com/files/sdr/26-May-2019%20204058.608%2013.258MHz.wav

I'm not entirely sure what this signal is. It's centered on 13260300 Hz with a bandwidth of 10kHz. The waterfall pattern has me puzzled, the smoothness and "liquidity" of the signal suggests it's not a trunked data. I've done a bit of looking around and not had any ideas that are close to what this is.

All of the fun with SDR over the past month or so has led me to ordering myself an Airspy R2 and Spyverter, and a few other bits and pieces like an LNA and an FM block. It'll be interesting setting all of those up.

Anyone got any ideas as to what this odd signal could be?

submitted by /u/cathalferris
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RTL-SDR Discussion • Using SDR and computer to send data over internet

Hello, I'm new to radio communications, and I apologize for my lack of understanding. I use a high-accuracy RTK GPS system for auto guidance on agricultural equipment. This system uses a minimum of 2 GPS receivers - 1 stationary as a base station, and one rover on each vehicle using the guidance (multiple vehicles can use the system at the same time). All receivers have 900mhz radios on them so they can send GPS corrections to each other. As long as the receivers are within about 12 miles of each other, full accuracy is maintained.
The issue I have is that the 900mhz radios only give me a fraction of the system's 12 mile accuracy range. Rolling terrain and trees block the 900mhz signal once I get only a couple miles away from the base station. The radios would work great if they were always in line of sight with each other, but that's not very practical.
Here's what I would like to do:
1. Receive the 900mhz base station signal with a nearby internet-connected laptop and SDR
2. Send the data over the internet to another internet-connected laptop with second SDR in the vehicle cab
3. Transmit the data at 900mhz to the vehicle receiver using the second SDR, just as the base station would if the vehicle was in radio range with the base station.

I don't need to manipulate the 900mhz signal. I just want a pass-through pipeline of data over the internet, so the exact same signal being broadcast from the base station is broadcast from the SDR in the vehicle cab to the rover receiver.

Seems like this could be achieved somehow with SDRs, but I don't really even know how to get started. I would appreciate any input on if this is possible, and if so, what is the best way to do it economically. Thanks!

Statistics: Posted by rty — Sun May 26, 2019 10:52 pm

KerberosSDR • Re: Power connection question

kb3cs wrote:
Sun May 26, 2019 1:04 pm
interesting, as i have a Pi3B+ and have yet to observe it pull more than 2A with any of the workloads i have presented it so far.
If the Pi3 doesn't get enough power, but still enough to run, it will simply throttle down the CPU. That makes the update rate of the Kerberos software very slow.

If I use even a 2.4A supply with the Pi3, Raspbian displays the yellow lightning symbol on the top right, and it will never throttle up.

Statistics: Posted by rtlsdrblog — Sun May 26, 2019 10:06 pm

Yaroslav Proshkin

Прохождения на си-би

Прохождения на си-би (00:01:25)

There are more satellites besides noaa and meteor that can be captured?

There are more satellites besides noaa and meteor that can be captured?

I've seen images of the whole earth in other posts and I would like to know if apart from these common satellites you could capture more

PD: I'm in Europe :D


submitted by /u/echo7722
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Advice on how to get raw data from USB

I am learning to program (in Java) and would like to communicate and receive data with my old RTL dongle. Is there any info out there for how to do this (or rather, info for someone who is not a 25 year C vet)?

submitted by /u/0x43_0x57
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Comment on Manual Installation of SDR# by anonym8

Works great for me. I suspect that most these comments are malfunctioning people. Computer only does what you tell it.

RTL-SDR Discussion • Re: ExtIO_RTLSDR# — custom ExtIO for RTLSDR

A little update v1.0.0.2:
- fixed RTL device initialization (previously it has some uninitialized state at startup)
- changed level scale to be equal with 8 bit ExtIO mode (this ExtIO uses FLOAT sample format in order to support DC filter)
- reduced DC filter damping factor for a little (for better DC filtering with fast changing signal)

Statistics: Posted by qrp — Sun May 26, 2019 5:52 pm

Is there an equivalent to GOES that you can access from europe, africa? I knoe about meteosat, but it seems like they are encrypted

submitted by /u/PayDaPrice
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