Архив за 07.12.2017

Comment on Several new Airspy HF+ Reviews by Max

AirSpyHF+ vs netSDR Shootout | RadioHobbyist.org

Troubleshooting Help • Re: Static or noise at Raspberry Pi’s

Now i've tried something else which has influence on these signals. I used an good usb extension cable which gave more static but little lesser static. If I hold the usb metal in my hand, at the dongle side, the static reduces a lot and the real signals become a lot more clear. The 'spooky' signals are still present, but way less.


This post says there is some sort of design flaw with the sdr dongle. To reduce RFI they advise to not connect the usb shield. Maybe this has something to do with it.
https://www.rtl-sdr.com/tip-reduce-radi ... e-rtl-sdr/
http://sinnet3000.blogspot.nl/2013/03/r ... l-sdr.html
http://www.radioforeveryone.com/p/reduc ... noise.html

Morgen maar even proberen..

Statistics: Posted by sjonkeesse — Thu Dec 07, 2017 11:09 pm

RTL-SDR Discussion • Re: LF antenna and ampflication. How?

The reader is just a single ic, you cannot pick up the signal from it but you need another transceiver beside that can receive, save in a buffer and trasmit with more power. But then what do you use to receive this more powerfull signal?
Is the standard receiver always listening or just for a fracion of a second after it has sent a request? I have never seen a RFID receiver for passive tags, i suppose that it is not continuosly trasmitting but you need to press a button to send the request and only then it starts receiving. For how long?
Every single sequence has to be tested but at the end I don't think that you can make a small portable device to do this.

Statistics: Posted by m_a_x — Thu Dec 07, 2017 9:36 pm

Monitoring a band and saving signals above a threshold for offline analysis

I've been playing with rtl_433 and I was wondering if there is something similar but instead of monitoring just a frequency (or a set of frequencies), is able to monitor a band (like, for example, the entire 2m ham radio band) and saving only the signals that crosses certain strength threshold (I tried to record all I/Q samples but that consumes a lot of disk space). Then, you can demodulate them later using GNU Radio.

submitted by /u/Antifa_-_-_y
[link] [comments]

radio beacons?

i'm experimenting with radiolocation using SDR and these transmitter modules. they work pretty well, but i'm interested in trying other frequencies, say in the 150-300 MHz range. any suggestions regarding what to look for, or how to go about making my own?

submitted by /u/chronopoul0s
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Comment on The Open Source OVI-40 SDR Transceiver by DF8OE

Sorry – that is only a small part. You do not need common software. All is implemented in firmware. It will be “standalone”. And that is the base why mcHF and OVI40 *are SDR transceivers*… You can extract IQ -data for external use. But if you only want to listen SSB, AM, FM, CW – you do not need external software.

Troubleshooting Help • Re: Static or noise at Raspberry Pi’s

I've tried it all, i've used three different pi's (1x zero, 2x model 3). Because of the differences in result between models, I thought maybe I can trie some other boards. So I just tried an Asus Tinker Board. This board has a dedicated chip for the usb connection, where the raspberry pi's has a shared chip for usb and ethernet.

This time I tested three devices at the same time at the same place; macbook, pi model 3b, asus tinker board.

All devices runned a version of keenerd's rtl-sdr library. I ran this command for each device:


rtl_power -f 383M:385M:1k -i 1 -g 50 -P output.csv
With these results:

... so there are additional signals visible with the pi and thinker board, at different frequencies.

The naked sdr sticks are the same as the one with the case.

Even known at this picture they are all standing next to each other, I also tested this with greater distance.

Statistics: Posted by sjonkeesse — Thu Dec 07, 2017 8:22 pm

RTL-SDR Discussion • Re: Before / After comparison?

how about one of those two?

Statistics: Posted by dlritter — Thu Dec 07, 2017 8:12 pm

Comment on The Open Source OVI-40 SDR Transceiver by KC3KCQ

It used UHSDR so I assume the functionality will be similar to that of the mchf/rs-918. Which the later can be used as an SDR frontend, outputting IQ data to common software like HDsdr and SDR#.

You can read more about it at the following link:


“SDR Programs for use with IQ Data”

Comment on Recent Updates to the JAERO L-Band and C-Band AERO Decoder by Tim

No, I launch it from the same desktop shortcut.
So same version app…… what brand of virtual cable you using? Perhaps I can test it out on one of my virtual machines.

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