Search found 177 matches

by hotpaw2
Mon May 10, 2021 12:19 am
Forum: Troubleshooting Help
Topic: Incoherent spikes in direct sampling mode.
Replies: 1
Views: 163

Re: Incoherent spikes in direct sampling mode.

Those could be noise spikes caused by harmonics from a nearby 100 kHz power supply or other noise generator (solar panels, LED lights, USB chargers, etc.). Try running your RTL-SDR from a portable laptop/notebook computer on a picnic table far (1000's of meters) away from the nearest buildings, sola...
by hotpaw2
Wed Apr 21, 2021 3:03 pm
Forum: Off-Topic
Topic: Wide spectrum analyzer
Replies: 1
Views: 995

Re: Wide spectrum analyzer

The TinySA spectrum analyzer goes from 100 kHz to 960 MHz, with over 300 MHz of bandwidth. Seems to be available from various vendors for between $50 to $100. https://www.tinysa.org/wiki/
by hotpaw2
Tue Apr 20, 2021 4:01 pm
Forum: Other SDR Devices
Topic: how good is Luowave's "USRP LW 1"?
Replies: 3
Views: 2046

Re: how good is Luowave's "USRP LW 1"?

For over $200 (USD) less, you can get a direct sampling SDR with slightly higher 76 MHz sample rate 12-bit ADC, and a much faster Gigabit ethernet connection. It's the Hermes Lite 2. Several hundred built. I have a couple. Component quality from Makerfabs seems excellent. If you want more bits for a...
by hotpaw2
Fri Apr 16, 2021 5:21 am
Forum: RTL-SDR Discussion
Topic: How to develop own software for scanning frequencies and checking for radio activity
Replies: 1
Views: 243

Re: How to develop own software for scanning frequencies and checking for radio activity

There are several tutorials on writing programs for the RTL-SDR.
Here's one for Python, mentioned on this site:
https://www.rtl-sdr.com/developing-your ... th-python/
Google will find others.
by hotpaw2
Mon Apr 12, 2021 6:07 pm
Forum: RTL-SDR Discussion
Topic: Why do I need an SDR?
Replies: 3
Views: 1039

Re: Why do I need an SDR?

Depends on if you want to receive local stuff on your own antenna, and not depend on the internet working or someone else's server to be up and running and not busy.
by hotpaw2
Sat Apr 10, 2021 6:12 pm
Forum: RTL-SDR Discussion
Topic: SDR-RTL for longwave and mediumwave
Replies: 3
Views: 591

Re: SDR-RTL for longwave and mediumwave

An RTL-SDR V.3 in Direct Sampling mode might work. But if you can afford to pay for a more expensive SDR, consider the Airspy HF+ Discovery or SDRPlay RSPdx for more dynamic range, less likelihood of overload, and perhaps better sensitivity in the LF and MF frequency ranges,
by hotpaw2
Thu Mar 04, 2021 6:37 pm
Forum: RTL-SDR Discussion
Topic: Why Can't I Grasp This?!?
Replies: 6
Views: 769

Re: Why Can't I Grasp This?!?

The RTL-SDR operating receive frequency has to be set by software. That receive frequency is not stored in the RTL-SDR when power is removed, but has to be set by software each time the unit is started. However, some RTL-SDR units have a band-pass filter in front of the tuner, set to certain aviatio...
by hotpaw2
Mon Feb 22, 2021 5:58 pm
Forum: Antennas
Topic: Best antenna for HF
Replies: 8
Views: 2259

Re: Best antenna for HF

Check the noise floor at your antenna location. If you can see a raised noise floor on your SDR's spectrum display when you attach a small loop antenna, then a larger quarter or half wavelength antenna won't really improve your reception. Physics says that not only will a better antenna pick up more...
by hotpaw2
Mon Feb 15, 2021 7:07 pm
Forum: User Projects
Topic: A potential work-around for multiple RTL devices with their own spyserver
Replies: 5
Views: 4849

Re: A potential work-around for multiple RTL devices with their own spyserver

My overly-simplified method of running multiple SDR dongles without any device ID issues is to use a separate Raspberry Pi for each USB dongle. I co-locate the Pi's and SDRs near my antenna distribution panel. Then I run all the networked Pi's remotely from a Mac.
by hotpaw2
Thu Feb 04, 2021 5:18 am
Forum: RTL-SDR Discussion
Topic: RTL-SDR as a down-converter?
Replies: 1
Views: 409

RTL-SDR as a down-converter?

Has any one tapped the output of the R820T2 to use an RTL-SDR as a downconverter from VHF or UHF to HF? That way one could use an HF-only receiver or direct-sampling SDR to receive higher frequencies than the receiver supports. For instance, one could use an HF SDR with a 16-bit ADC instead of using...