Search found 101 matches

by hotpaw2
Sat Apr 08, 2017 6:25 pm
Forum: Troubleshooting Help
Topic: IP Address Format & Source
Replies: 4
Views: 4241

Re: IP Address Format & Source

Is the RTL-SDR plugged into your PC's USB port?

Are you trying to connect from your Android phone to a server on your PC?

Is your PC running a firewall?
by hotpaw2
Sat Apr 08, 2017 6:17 pm
Forum: User Projects
Topic: Using satellite doppler effect to determine position
Replies: 4
Views: 5104

Re: Using satellite doppler effect to determine position

This requires a frequency reference much more stable than the amount of satellite doppler shift. Not sure the oscillator ppm spec on an RTL-SDR meets this criteria. Maybe by wiring in an external higher quality frequency reference?
by hotpaw2
Sun Mar 19, 2017 5:14 pm
Forum: Troubleshooting Help
Topic: "usb_claim_interface error" occurred
Replies: 9
Views: 20949

Re: "usb_claim_interface error" occurred

"rtl_test" does not work on Raspberry Pi3 properly. >usb_claim_interface error -6 >Failed to open rtlsdr device #0. I got a similar error under the latest Raspian, I found I had to change the build script to use this line: cmake ../ -DINSTALL_UDEV_RULES=ON -DDETACH_KERNEL_DRIVER=ON Not sure why...
by hotpaw2
Wed Mar 15, 2017 4:51 pm
Forum: RTL-SDR Discussion
Topic: How to count and identify carrier frequencies?
Replies: 13
Views: 7615

Re: How to count and identify carrier frequencies?

The source of the interference would be interesting. Any idea how to locate them with simple tools? If you are using a USB RTL-SDR, the simplest tools to start with to find the source(s) might be 2 cables and some ferrites. Use a USB extension cable to move the RTL-SDR as far away from any computer...
by hotpaw2
Thu Mar 09, 2017 1:27 am
Forum: Troubleshooting Help
Topic: rtl-sdr/tcp
Replies: 6
Views: 8515

Re: rtl-sdr/tcp

That error message might imply that you have a firewall enabled on the computer running rtl_tcp. You might want to look up the command to turn off the firewall for port 1234 (or whatever port you are using). One huge reason to use rtl_tcp is that opening a network socket may be far simpler than tryi...
by hotpaw2
Wed Mar 08, 2017 6:21 pm
Forum: RTL-SDR Discussion
Topic: Why does LTE use so much bandwidth?
Replies: 4
Views: 3664

Re: Why does LTE use so much bandwidth?

IIRC, LTE uses a variation of OFDM, which is the equivalent of splitting up and spreading the data out over many many channels simultaneously. That provides both bandwidth and resistance to interference and multi-path nulls, and might be easier to demodulate if have a chip that can do tons of very f...
by hotpaw2
Wed Mar 08, 2017 5:48 pm
Forum: RTL-SDR Discussion
Topic: How do I use RTL-TCP?
Replies: 10
Views: 17983

Re: How do I use RTL-TCP?

Basic use of the rtl_tcp protocol is extremely simple. Open a generic bidirectional TCP socket (default port 1234). Uplink control is by sending 5 byte units, 1 byte command, 4 bytes of data (32 bit integer in little-endian format). You can get by with as few as 4 or 5 commands. Here are a few of th...
by hotpaw2
Wed Mar 08, 2017 5:34 pm
Forum: RTL-SDR Discussion
Topic: Replace vehicle radio with rPi and RTL-SDR?
Replies: 3
Views: 3118

Re: Replace vehicle radio with rPi and RTL-SDR?

A vehicle radio has lots of front-end filtering (band-pass for the broadcast spectrum of interest) and shielding (from vehicle generated RFI and power-bus noise). Adding all that to a rPi + RTL-SDR would likely be required to get a decent signal. A cheap FM tuner hat for the rPI might be another pot...
by hotpaw2
Wed Mar 08, 2017 5:19 pm
Forum: Other SDR Devices
Topic: anyone done a comparison with the flights aware pro stick?
Replies: 2
Views: 3485

Re: anyone done a comparison with the flights aware pro stic

I have one of each. The FlightAware USB dongles have a front-end RF amplifier (LNA) built-in, which increases their sensitivity (thus range), but also how easily they can get overloaded by any other nearby RF signals. I can see that in some of my waterfall plots. So it's recommended that you use the...
by hotpaw2
Wed Jan 18, 2017 9:08 pm
Forum: RTL-SDR Discussion
Topic: Running a dongle on a networked PC ?
Replies: 13
Views: 9594

Re: Running a dongle on a networked PC ?

For my iOS devices, nothing else was available, so I've coded my own SDR software completely in Swift 3, including all the filters, some demodulators for AM and FM, and some spectrum viewers. Nice any plans to put your app on the iOS store? I've been working with at least one other developer who is...