Search found 113 matches

by hotpaw2
Sat Aug 10, 2019 6:06 am
Forum: Other SDR Devices
Topic: Any good full-duplex SDRs?
Replies: 8
Views: 3303

Re: Any good full-duplex SDRs?

The LimeSDR Mini is available from the CrowdSupply online store: https://www.crowdsupply.com/lime-micro/limesdr-mini I had no problems ordering one, just like from any other online store. The unit arrived about a week after ordering, and worked right out of the box. The LimeSuite software library fo...
by hotpaw2
Fri Aug 02, 2019 10:09 pm
Forum: User Projects
Topic: I need some advice in creating IQ processing software
Replies: 6
Views: 1783

Re: I need some advice in creating IQ processing software

A few million IQ samples per second isn't really fast on any modern CPU (including those on mobile devices and Raspberry Pi's) which can perform Billions of floating point operations per second. You may have to use a moderately optimized FFT library, but there are many libraries (other than FFTW) av...
by hotpaw2
Fri Jul 19, 2019 2:36 pm
Forum: RTL-SDR Discussion
Topic: Data buffering of rtl
Replies: 3
Views: 1164

Re: Data buffering of rtl

Even a Raspberry Pi 3 running rtl_tcp doesn't buffer 5 seconds of data on a fast network. Depending on the sample rate, maybe 1 second or less, mostly from the USB transfer bursts. The SDR software maybe needs to buffer another half second, depending mostly on network and OS latency jitter. Audio ou...
by hotpaw2
Mon Jul 15, 2019 4:56 pm
Forum: Off-Topic
Topic: What (besides sw compatibility) is needed for SDR?
Replies: 2
Views: 1360

Re: What (besides sw compatibility) is needed for SDR?

USB hardware devices are allowed by the USB spec to have completely different profiles. Just because the connector looks the same does not mean that the profile supported is the same. A USB flash drive is quite different from a USB audiophile DAC. Different USB profiles. And you can only communicate...
by hotpaw2
Sun Jul 14, 2019 4:12 pm
Forum: Other SDR Devices
Topic: SDR radio kits to assemble?
Replies: 2
Views: 1472

SDR radio kits to assemble?

Are there any electronics kits available, requiring assembly from schematics, PCB(s) and components, for SDR experimentation? Or do all the surface-mount components required make this too difficult?
by hotpaw2
Mon Jul 01, 2019 4:26 pm
Forum: Troubleshooting Help
Topic: Spikes on HF frequency
Replies: 8
Views: 3126

Re: Spikes on HF frequency

Those periodic spikes and waves look like the symptoms of electronic switching RF noise. This kind of RF noise can be generated by LED lights, power supplies, network equipment (cable modem, WiFi/ethernet hubs, etc.), PCs, monitors, printers, and etc. Not only in your place, but from inside any near...
by hotpaw2
Mon Jul 01, 2019 12:38 am
Forum: Troubleshooting Help
Topic: Has anyone managed to get a Raspberry Pi 4 working with an RTL SDR?
Replies: 11
Views: 6280

Re: Has anyone managed to get a Raspberry Pi 4 working with an RTL SDR?

A bunch of us are probably still waiting for more Pi 4's to be in stock and ship.
by hotpaw2
Tue May 28, 2019 1:06 pm
Forum: RTL-SDR Discussion
Topic: Using SDR and computer to send data over internet
Replies: 3
Views: 1253

Re: Using SDR and computer to send data over internet

Whether possible depends on the protocol used by the 900 MHz radios (e.g. any message response latency requirements, etc.). If possible, it would require some full duplex SDR radios, such as the Hack RF, LimeSDR, Ettus Research, and etc. which are more expensive than RTL-SDR plug-ins.
by hotpaw2
Fri May 24, 2019 6:59 am
Forum: RTL-SDR Discussion
Topic: Sigmira: Sr. Citizen Woes
Replies: 4
Views: 1273

Re: Sigmira: Sr. Citizen Woes

Why not ask the sigmira developer? Probably knows a lot more than anyone here.
by hotpaw2
Tue May 21, 2019 3:15 pm
Forum: Troubleshooting Help
Topic: Signal chain w/ RTL-SDRBlog Dongle v3 + RTLSDRBlog Wideband LNA & FM Filters?
Replies: 2
Views: 888

Re: Signal chain w/ RTL-SDRBlog Dongle v3 + RTLSDRBlog Wideband LNA & FM Filters?

Actually, there is a trade-off. One solution does not fit all. A short coax run between the antenna and the LNA or SDR radio means less signal attenuation. But, unless you are on the very top of a hill and off-the-grid, one usually gets better reception and less RF interference by putting the antenn...