Search found 101 matches

by hotpaw2
Mon Apr 08, 2019 12:18 am
Forum: Other SDR Devices
Topic: List of HF SDR Transceivers
Replies: 5
Views: 1521

Re: List of HF SDR Transceivers

Also:

LimeSDR Mini

Raspberry Pi with an RTL-SDR (direct-sampling or with an upconverter) plus a narrow-band HF filter such as the TAPR 20M TX shield for use with PiTX.
by hotpaw2
Thu Apr 04, 2019 3:36 pm
Forum: RTL-SDR Discussion
Topic: Install drivers RTL-SDR on MAC HIg Sierra
Replies: 10
Views: 1719

Re: Install drivers RTL-SDR on MAC HIg Sierra

Never heard of "Touctone", but there are lots of "drivers" (actually libraries) for RTL devices that run on macOS. If you don't want to compile your own librtlsdr library using Xcode tools, you can use the ones built into Gqrx, or these pre-built ones for macOS from a UC Berkeley DSP course site: ht...
by hotpaw2
Thu Apr 04, 2019 3:29 pm
Forum: RTL-SDR Discussion
Topic: Do I have latest linux driver?
Replies: 3
Views: 906

Re: Do I have latest linux driver?

There may be no "best" server, as different forks and different servers have different improvements, some too new or experimental to make it into the Osmocom branch. However, the Osmocom branch is probably the best for general new users.
by hotpaw2
Tue Apr 02, 2019 4:55 pm
Forum: RTL-SDR Discussion
Topic: quick question about RTL SDR dongle
Replies: 5
Views: 1016

Re: quick question about RTL SDR dongle

The bandwidth of an RTL-SDR is far too narrow to allow listening on two widely separated frequency bands. However your server might have enough USB ports to allow plugging in 2 RTL-SDRs, each tuned to a different band, one for 1090, the other for airband, etc.
by hotpaw2
Tue Apr 02, 2019 4:44 pm
Forum: RTL-SDR Discussion
Topic: RTL-SDR Samplerate
Replies: 2
Views: 756

Re: RTL-SDR Samplerate

An RTL-SDR outputs 8-bit IQ components, which, at 2 components per sample, adds up to 16 bits per IQ sample. The lowest sample rate the RTL2832U supports for USB data is 240ksps. To stay under 1 a megabit network cap would require a sample rate of under 1M/16, or 62.5k samples per second (or 0.0625 ...
by hotpaw2
Tue Mar 26, 2019 7:43 pm
Forum: Antennas
Topic: Multi-purpose Dipole loose pivots?
Replies: 1
Views: 703

Multi-purpose Dipole loose pivots?

The two longer antennas on my RTL-SDR Blog Multipurpose Dipole Antenna Kit just flop over to the side.
Can the antenna pivot points be tightened up?
If so, what kind of screwdriver (Phillips, Torx, hex, size?) should be used to tighten them?
by hotpaw2
Wed Mar 13, 2019 8:29 pm
Forum: User Projects
Topic: New SDR app for iOS (iPhone)
Replies: 5
Views: 8779

Re: New SDR app for iOS (iPhone)

An update to my rtl_tcp SDR app for iOS (iPhone) should now be in Apple's App store. https://itunes.apple.com/us/app/rtl-tcp-sdr/id1351164646?ls=1&mt=8 The rtl_tcp SDR version 1.0.7 update includes: - support for the SDRPlay rsp_tcp 16-bit mode for a better signal-to-noise ratio - a much improved co...
by hotpaw2
Tue Mar 12, 2019 5:40 pm
Forum: RTL-SDR Discussion
Topic: FM Radio reception
Replies: 7
Views: 9444

Re: FM Radio reception

The issue is likely the antenna size, orientation, and location in your dwelling. I can make some FM stations disappear just by turning the antenna on my RTL-SDR sideways. Even with more expensive rtl_tcp work-alike SDRs, such as the Airspy HF+ or SDRPlay 2.
by hotpaw2
Sat Mar 02, 2019 4:46 pm
Forum: User Projects
Topic: IQ to frequency spectrum with FFT - half of bandwidth?
Replies: 2
Views: 1118

Re: IQ to frequency spectrum with FFT - half of bandwidth?

Make sure you are sending both I and Q channels to a single complex-to-complex FFT. Use N samples of I and N samples of Q to create N complex samples for a length N FFT. Don't use 2 real-only FFTs or a complex FFT with all the imaginary components zero, instead of Q data. (Read up on complex numbers...
by hotpaw2
Wed Feb 20, 2019 12:54 am
Forum: User Projects
Topic: How exactly are the IQ channels supposed to be calculated/processed?
Replies: 2
Views: 6705

Re: How exactly are the IQ channels supposed to be calculated/processed?

Note that: (x+iy)*(x-iy) = x^2 + y^2 so a * (cos(w) + i*sin(w)) * (cos(w) - i*sin(w)) = a * (cos(w)^2 + sin(w)^2) = a * 1 = a where w = 2 * pi * f * t Both e^iw and e^-iw are used to get e^0, which leaves the original RF signal unchanged. Note that simple multiplication can be used for the first het...