Search found 86 matches

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: 392

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: 399

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: 262

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...
by hotpaw2
Mon May 20, 2019 11:46 am
Forum: RTL-SDR Discussion
Topic: Raspberry pi 3 b+ and rtl-sdr
Replies: 2
Views: 309

Re: Raspberry pi 3 b+ and rtl-sdr

Would you like to use your Pi with a monitor and keyboard attached? Or headless, as a remote RTL-SDR rtl_tcp server? For the latter, I just use the Raspbian Stretch Lite OS image, boot it up, then download and and run the rtl-sdr install scripts via ssh. There are a bunch of SDR client apps that wil...
by hotpaw2
Thu May 16, 2019 6:24 pm
Forum: RTL-SDR Discussion
Topic: LNA power supply?
Replies: 6
Views: 530

Re: LNA power supply?

Interesting. I've always assumed that unwanted interference was a subset of noise, not a disjoint set.
by hotpaw2
Tue May 14, 2019 7:36 pm
Forum: RTL-SDR Discussion
Topic: LNA power supply?
Replies: 6
Views: 530

Re: LNA power supply?

Yes, a linear regulator can pass supply RF noise through its transformer and drop-out impedance. But it's far less likely to generate RF noise of its own, as do almost all switching power supplies.
by hotpaw2
Mon May 13, 2019 3:40 am
Forum: RTL-SDR Discussion
Topic: LNA power supply?
Replies: 6
Views: 530

Re: LNA power supply?

Most 12V wall-wart power supplies use switching regulated voltage converters. A consumer-grade switching voltage regulator generates tons of RF noise, possibly not even meeting FCC part 15 RF emission regulations with the most cheaply made ones. Best bet, other than a primary battery, would be a lin...
by hotpaw2
Thu May 09, 2019 8:34 pm
Forum: Troubleshooting Help
Topic: I can't hear anything on MW and SW
Replies: 14
Views: 1450

Re: I can't hear anything on MW and SW

How big an antenna?

I barely hear any signals at all below 30 MHz (in Q/Direct Sampling mode) with an indoor whip antenna.

But I do hear some signals if I connect the RTL-SDR up to a 20M long wire antenna in the back yard.
by hotpaw2
Sat May 04, 2019 7:27 am
Forum: User Projects
Topic: rtl_tcp compatible server for the LimeSDR Mini
Replies: 0
Views: 292

rtl_tcp compatible server for the LimeSDR Mini

I recently acquired a new LimeSDR Mini USB SDR module. Not much bigger than an RTL-SDR, 10 MHz to 3.8 Ghz frequency range, 12-bit sampling, full-duplex, capable of a wider bandwidth than a Raspberry Pi can use. In order to test the receive function of the LimeSDR Mini using my existing SDR applicati...
by hotpaw2
Wed May 01, 2019 3:17 pm
Forum: Troubleshooting Help
Topic: About heat
Replies: 2
Views: 280

Re: About heat

Different brands of RTL-SDR dongles seem to require different amounts of power. Some dissipate significantly more heat than others. In my experience, the E4000 dongles run cooler, and one of my smaller NooElec dongles got so hot, it burned itself out.