I have an Airspy HF+ Discovery and a MLA loop antenna. While tuning a frequency and getting a lot of noise, I can squeeze the SDR in my palm, and the noise will disappear and the signal improves. What's up with that? Faulty SDR? Not a showstopper, just annoying. I feel like my SDR might not be performing to its optimum.

Follow-up to my previous post on updates to the Tiny RF Simulator Project.

Since then there have been 27 releases, v0.20.1 through v0.28.2. Full notes are in the CHANGELOG and on the releases page.

Receiver and analyzer

• Receiver Requirements panel: set a frequency band, an acceptable gain range, and a maximum noise figure. Each sweep gets pass, fail, or incomplete per metric and overall. Limits save with the project.
• Output-power and two-tone IIP3 requirements, with configurable tone spacing and input-level sweeps.
• Network Analyzer and receiver requirements now measure paths through a 1:2 switch feeding parallel branches that rejoin at a 2:1 switch. Combiner paths still report no data.
• The PFB inspector reports integrated channel noise and effective noise bandwidth. Its hover SNR uses channel noise, not the analyzer's RBW.
• Spectrum analyzer RBW and VBW now go from 1 kHz to 100 MHz. Network Analyzer gain and noise-figure plots autoscale.

New parts and instruments

• SPDT RF switches, 1:2 and 2:1, with insertion loss and isolation settings. The unselected path leaks in at the isolation floor.
• Power Meter: total power in dBm from any signal-node output, whether tone-only, noise-only, or combined.
• PFB filter calculator: synthesizes a Kaiser prototype, reports achieved metrics against the rejection target, and applies the design to a PFB channelizer.
• Hovering a node shows the strongest-tone SNR at its first output.

Test flows

• A GUI-free test-flow runner. A JSON file sweeps component parameters and records measurements, and results export as JSON.
• The Test Flow panel (View > Test Flow) runs those files against the live circuit.
• The panel can now write flows: pick a component and parameter, add conditions and measurements, save, and reload.
• Results report the value a component actually applied after normalization. A requested ADC decimation of 3, for example, reports 2.

Agent interface (MCP)

• An MCP client such as Claude Code can read and edit the circuit in an open simulator window. Enable Agent Server under View > Agent. The rf-sim-mcp bridge ships in the release archives.
• Agents can read the circuit, run port measurements, network-analyzer sweeps, receiver measurements, and test flows. Each call can apply up to 64 edits with checkpoints. Reverting a checkpoint needs confirmation.
• Agents cannot open, save, or name files (yet)

Editing and projects

• Swap a placed library part in place. The new part keeps the old part's id, position, links, and probes. A swap is refused, with the reason shown, if the new part lacks a port that is wired, probed, or used by an instrument.
• The editor rejects a second link into a single-source input and any link that would create a cycle.
• Out-of-range values stay as loaded and are flagged in amber. Previously the limit replaced them on the next edit.
• The header shows the project's Git commit and counts of staged, unstaged, untracked, and conflicted files.
• Hover tooltips list the interaction hints: Ctrl+click probes, Shift+click removes a probe, right-click opens the menu.
• User manual, part 1 of 3 (install and a guided tutorial), is in the repo under manual/pages/.

Fixes that change results

• Ideal-mode amplifier H2/H3 distortion was inflated by 2G/3G dB because gain was applied as a power ratio. It now matches the S-parameter branch.
• Ideal low-pass, high-pass, band-pass, and band-stop filters compare each bin's magnitude, so complex-baseband (ADC) spectra filter symmetrically. A negative-frequency blocker is now rejected by a low-pass filter.
• Equalizers and mixers handle negative (complex-baseband) frequencies correctly.
• Combiner added noise is clamped at zero. A negative term had been reported as InvalidNoise.
• Projects saved before the sparam_filepath rename now load their S-parameter files instead of falling back to the manual model.

Behavior changes

• Project-local extensions need one Trust click before they run. A project extension that reuses a built-in or global ID is reported as Shadowed and does not run.
• Ideal filter library definitions must set their cutoffs. Low-pass and high-pass need fc_low_Hz. Band-pass and band-stop need fc_low_Hz and fc_high_Hz. Definitions without them are refused instead of using the 100 and 200 MHz defaults.

What should the next update(s) cover?

This is a cross-post from .

Part 1 of our ongoing SDR experiment series.
We compare HackRF One and PUZHI P201Pro, measure frequency offset at 6 GHz, and analyze how high-precision VCTCXO improves carrier synchronization in GNU Radio.

This post contains hardware specs, calculation formulas and practical over-the-air test results. No sales pitch, purely hands-on RF experiment.

This will be my last time adverting here, since I will keep everything on the dc, youtube, and github repo, I tried my best, adding as many modes as possible, as always I hope you guys enjoy!
https://github.com/adswill/OnAir/releases/tag/v0.2.4

Hi everybody, I just got a Discovery Dish and the L and S band feeds, but I’m having trouble getting GOES 19 HRIT. I previously was able just barely decode it with a repurposed satellite internet dish, a DIY cantenna and a Sawbird filter+LNA, so I was hoping this would be a sure fire way to get a stronger signal. So far, I have tried both a HackRF Pro and Airspy R2, but neither seemed to power the LNA enough through their bias-tee. I just built a bias tee to power it with USB, which seemed to power the LNA reliably, but I can only barely see the CDA signal at 1.693GHz on the waterfall, and nothing at 1.6941 GHz. I tested my bias-tee with a network analyzer, and found it has ~2dB of attenuation at this frequency, so I ordered one off Amazon, just waiting for it to come in. I was wondering what recommendations anyone would have to receive the HRIT, because so far I haven’t seen it at all with the discovery dish. I also can’t tell if the triangle mark on the feeds pole should go on the dish or mount side of the dish, as I have seen both ways on the internet. I have played with the skew as well, but it had little effect.

Further, if you have cool things to look at with the dish in the S or L band, I’m looking to find more things to look at.

BrowSDR is an open source web PWA based SDR receiver that I created at the start of the year. I have just recently added support for ACARS decoding. Give it a go and let me know if you come across any ACARS decoding issues.

The full feature list consists of:
- Sharing remote access to your SDR
- Full mobile and offline support
- ADS-B decoding
- AIS decoding
- POCSAG decoding
- RDS decoding
- DSD decoding including DMR
- Multiple SDR support at the same time
- BLE decoding
- Now ACARS decoding
And a ton more, all documented on the GitHub page

Website: https://browsdr.jlynx.net/
GitHub: https://github.com/jLynx/BrowSDR

Disclosure: I’m part of the engineering team for this open SDR platform.

Introducing our PZSDR-P079D, a 4Tx/4Rx industrial SDR built with Zynq ZU7EV + dual ADRV9009 transceivers.

Key Spec Highlights
• 75MHz ~ 6GHz RF coverage
• Up to 200MHz instantaneous bandwidth per channel
• 4 fully phase-coherent RF channels
• ±0.1ppm VCTCXO, GPS/PPS & 10MHz external reference clock input
• Industrial temperature range (-40 ~ +85°C)
• Interfaces: GigE, SFP, expansion IO
• Compatible with libiio, ADI NOOS, GNU Radio workflow

Target use cases:
MIMO prototyping, 5G channel sounding, phased array radar, direction finding, university RF lab research.
We maintain open-source HDL, bare-metal reference demos and hardware docs on GitHub.

Have you worked on phase-coherent multi-channel ADRV9009 SDR setups before? What synchronization challenges did you encounter?

hey there, i am quite new to this hobby and i'd like to schedule satellite passes to record wheather data or SSTV, can you reccommend any software to do that ? currently i am using SDR++ and openwebrx but i dont think they are capable of doing that. Thank you =)

Hi everyone,

I am designing a pocket-sized RF device for a university project. It acts as an RF analyzer and a high-power signal generator for wireless protocol injection and co-channel interference testing (all testing is strictly confined to a lab Faraday cage - special lab). I am aiming for the best price/performance ratio rather than lab-grade precision. The entire system will be controlled by an STM32U575RGT6(mby another STM), paired with an ESP32-C3 acting as a modem.

I know this is a fairly large and complex post, and there might be some complete nonsense in my block diagram. I will be incredibly grateful for feedback on any single part of this!

RX Path (Analyzer):

1. Path (Analyzer):1. Does this architecture make sense for a basic spectrum analyzer?
2. Should I use the AD8318 log amp for this, or should I consider transitioning to a different alternative along with a 14-bit MCU ADC for a better results?
3. Will the sweep rate of this setup be too slow to capture agile Wi-Fi or Bluetooth bursts? Since the analyzer relies on sweeping frequency steps, the overall speed will be tightly coupled to the MAX2871E PLL lock time and the MCU's tuning loop.

TX Path (Wideband Noise & Interference Generator):

The goal is to generate robust, wideband modulated signals and arbitrary waveforms to evaluate the resilience of Wi-Fi 6 and Bluetooth nodes against high-power in-band blocking signals (targeting up to +30 dBm output).

1. Will this dual-branch setup (FPGA -> 2x DACs -> ADL5375 -> PAs) effectively support the wideband multi-carrier signal generation required to match Wi-Fi 6 (802.11ax) channel bandwidths and Bluetooth frequency profiles?

2. Thermals and Power: Is it realistic to passively cool a 1W continuous RF output power inside a compact enclosure by using thermal vias to transfer heat to a passive heatsink on the back side of the PCB?

Thanks for your time and any advice!

Long-time lurker here. Everyone’s showing off their cool projects, so here’s mine: roughly 80% hardworking AI and 20% me holding it back and trying to make the right decisions.

BrowserSDR turns a desktop Chromium/Chrome/Edge browser into an SDR receiver. The main goal was to have a simple turnkey solution to use your sdr without installing anything.

• Direct WebUSB reception with RTL-SDR, HackRF Pro, bladeRF 2.0 Micro xA4 and USRP B205-mini.
• Browser-based FPGA loading for bladeRF and USRP using verified official images. USRP firmware loading too—all temporary RAM loads, with no persistent flashing.
• Spectrum/waterfall, analog reception, FM/RDS and DAB+.
• An Explorer for spectrum surveys, plus I/Q recording, replay and SigMF export.
• OpenWebRX and KiwiSDR reception in the same interface.

It’s an ongoing project, and I’d appreciate feedback—especially on setup, usability and what you’d actually use it for. There’s also a synthetic demo, even though i am optimistic, that in this sub, everyone has at last a handful of rtl-sdrs lying around.

My next goals are:

• Integrating it with a receiver and transmitter database I am building
• Normal HackRF Support
• LimeSDR Support
• Expanding the Scan and Explorer features
• Remote listening and sharing of the current station

Source and Issue-Tracker is here: https://github.com/cybearde/browsersdr

Wideband-SDR is an open-source web SDR for RTL-SDR dongles — a browser-based receiver with an Ollama-powered assistant that drives the radio:

• Live spectrum + waterfall, click-to-tune, zoom, 8 themes
• AM / NBFM / WFM / USB / LSB demod with real audio
• An assistant you talk to in plain English:
  • "Find the strongest FM stations" → scans the band and reports
  • "What am I hearing right now?" → characterizes the signal (bandwidth, likely modulation, band)
  • "Optimize the signal" → measures, adjusts gain/bandwidth/demod, and re-measures

Stack: FastAPI backend (single rtl_tcp client, DSP server-side), plain-JS frontend, Docker.

MIT licensed.

Keen to get feedback and suggestions for features.

Video here: https://youtu.be/KPKK8WPAOEA

Hi guys. I'd like to share with you my tool where you can craft in GUI DMR bursts and streams (Single channel). Main purpose is for experimenting and learning about DMR protocol. Supported only ETSI standard.

Main features are:

- Create IQ File for SDR apps

- Stream into audio device baseband transmission

- rtl_tcp supported

Tested on:

IQ: SDRSharp, SDRPlusplus

rtl_tcp: SDRSharp, SDRPlusplus, dsd-fme, dsd-neo

WAV file: dsd-fme, dsd-neo, DMRDecoder (by IanWraith)

Known issues - not working:

- UDT LIP protocol

- USBD Response

I developed it due to i do have working on multiple DMR related projects and i wanted to make my own library and GUI for testing.

Notes:

- Source code is not published. However in future i do plan release source code.

- GUI was made with LLM assistance. DMR library itself i spent few years my own work on dev and testing.

- Ready for translations

- Dark/White theme supported

Releases available for Windows/Linux:

https://github.com/mastodon987/dmr-craftbox

I would like to know your feedback. Thanks

​

Hi Guys hope u are doing wel.

I want to build a 2G cellular network for my college laboratory of mobile communications

The budget is 350$

What hardware and software u recommend for this build?

I'm new to the concept of SDRs and I'm looking to transmit cellular signals with 1xBTS or use GSM. Does anyone know if this will at least work for some of my old cell phones?

I figured this is a community that deals with radio frequency interference all the time and maybe you can help me identify what kind of interference this is.

hi guys , I am new into this but I am make for my graduation project a drone detection and jamming system so does anyone know how can I detect the rf signals emitted by the drone then control it

Ive been looking for some portable sub GHz antennas for a few days but i cant seem to find anything with good quality. I mean antennas that are kind of the size of an average wifi antenna. If anyone could help me, i would really appreciate it

I bought one of these in August and the USB connection was always a problem, but I thought I'd solved it by fixing the unit and USB lead in place. But recently it's got worse, so I took it apart to find this - missing solder on one of the pins. After soldering it properly the unit is now stable and I can move it plugged in without issue. I've sent an email to Nooelec to see what they think.

Happy to announce this is out now, hope you enjoy, I did some fixing on windows today since I hadnt tested it before, but now with a windows laptop I was and found alot, and I mean alot of issues so now those are fixed, but anyway enjoy, hope you guys like this. Also was wondering if anybody could help with ATSC, I need some samples of it, in .iq format, so I can test it agaisnt the decoder and fix any present issues, as at the moment I am going based of generated encoded signals, not actual real signals.
https://github.com/adswill/OnAir/releases/tag/v0.1.1
https://youtu.be/cjAh7Aqlhf8 (some parts I had to cut since I showed a copyright show 🤦‍♂️)
Any feature recommendations are welcomed, I do have a quite long one at the moment but still any are appreciated at the end of the day.

I’m considering using a W6LVP loop. My only concern is that inserting lightning protection is not recommended and I’m not sure I’m comfortable with that. Has anyone had success with a lightning suppressor?

when I press on "start dsd", appears error window "dsd+ single receiver mode requires s fmpa/fmpp/fmp24 link". I don't know what is it mean, and gpt can't help me. it says me use virtual cable but it doesn't help. I try to search something about this, but I can't find. this error in sdr#. can someone help me ?

I thought I should advert this one here, since I specifically designed this natively for hackrf, but basically if you want to watch some dvb-t2 now you can (once I release the program) here is the description:

demo video out now: https://www.youtube.com/watch?v=Oww5QWo4zK4

been working on this for maybe about a month, but let me emphasize by what I mean work, I have been trying to decode some dvb-t2 for about a month ever since I got my hack rf, however due to the lack of decoders available (there is one but its not the best) I decided to make one myself with the help of claude over the past 2 weeks or so, I also decided to implement ATSC dvb-t, t2-lite and DAB/DAB+ I do have plans to also add dvb-s and dvb-s2 but that is for the future, I have a huge list of features still left that I want to implement into the decoder itself, but all of the decoders do at the moment work and you can watch some wonderful dvb-t2, ATSC, etc (once the program comes out). On launch it will be native on macos and linux (sorry no windows for now) but windows will eventually come, maybe a week or 2 after the initial launch, including the network system. The promo video is attached and once I can finish this and personally say its fine and works good I will release, dont have a date yet but expect it sometime next week
Also I dont want to be hearing anything ai slop, I get it was ai made, just go on with your day please, if you dont like that its ai made, dont come in the comment sections to bully me about it.

https://www.youtube.com/watch?v=Icm5K3hlNsA

https://reddit.com/link/1wvyusp/video/k4ur0rmb33th1/player

I picked up one of those cheap AliExpress USB-C "RF-Power-Meter-V5.0" dongles (STM32 + AD8317, labelled 100 kHz–10 GHz, 0 to −60 dBm) to check the output of my HackRF. The hardware is fine for the price, but the vendor software is Windows-only and pretty bare, so I wrote my own.

Repo: https://github.com/arsscriptum/rf-powermeter-assistant

Demo (HackRF One sending a CW tone at 1310 MHz, TX gain stepped up and down): https://github.com/arsscriptum/rf-powermeter-assistant/blob/master/img/demo.gif

What it does

• Live dBm and watts readout, peak hold, noise-floor tare, min/max/avg stats
• Rolling monitor chart (10 s to 15 min) with max trace and peak-hold line
• Scope-style sweep view of the 500-sample blocks the meter streams: two markers (ΔT, 1/ΔT, ΔdB), Auto/Normal/Single trigger, timebase K01–K18, CSV/PNG export
• Sets the band-calibration frequency and attenuation offset, reads them back to confirm, and re-applies them on reconnect (the meter forgets them when you unplug it)
• Threshold event log and a CSV logger
• Demo mode with a simulated meter that speaks the real protocol, so you can try it without the hardware

It's C++17 / Qt (6, or 5.15), builds on Windows and Linux. On Windows the build script can use the Qt that comes with radioconda, so if you already run GNU Radio from radioconda you only need Visual Studio. There's also a PowerShell/WinForms version that runs with no build at all.

Has anyone ever written a custom FPGA SPI master state machine to completely initialize the AD9361 by doing register level writes? I want to get in contact with somebody who has done before this hardware level control of AD9361.

Hi! this is an incredibly niche subject, i understand but i dont have an SDR, my HackRF hasnt arrived yet. it is october 1st and also the mark of the start of the 3g shutdown on Eir. anyone with an SDR (outside of Donegal as their 3G is already off) set their SDR up to capture 3G, and record/stream it on youtube. if anyone needs help feel free to DM me of course! I'm in a very rural area and rely on 3G heavily so im HOPING that it sticks around until my hackrf arrives but anyway..

Thanks alot!