Tell me, while I was waiting for the car, this map appeared on the dongle graph. Tell me, we have a digital weighing machine. If there's a theft going on with the remote, how can we catch it?

The battery on my old laptop died, so I gutted the pack and wired salvaged lithium cells to a BMS inside the chassis. It powers an ESP32 and an Ra-02 (SX1278) LoRa module running Meshtastic 2.7.15, through a buck converter set to 5V. There’s also a small battery level indicator on the lid.
Phone connects over Bluetooth fine, and I’m using the laptop itself as a Linux box to flash and configure.
• Clean up the wiring (it’s a prototype mess right now)
• Add an inline fuse
• Test range with a proper antenna
Any suggestions on power design or antenna placement are welcome. First time putting a node inside a laptop shell.

Some of you saw my earlier posts about getting raw I/Q out of the Semtech LR2021 (the LoRa chip on the LilyGO T-Display-P4). Spent the last couple days poking at the limits and figured I'd share what I found.

The tuning range is way wider than the datasheet says - 100 MHz to 2.74 GHz and streams 16-bit I/Q. Which is the most significant finding, but I’ll go more into detail below and have lots of info on the repo - https://github.com/SAMS0N1TE/lr2021-sdr

Live decoding (P25, POCSAG, FM) is in LakeShark if you want the handheld side: https://github.com/SAMS0N1TE/LakeShark

Datasheet claims 150 to 960 MHz and 1.5 to 2.5 GHz. I didn't have a signal generator handy for every band so I used the board's own 40 MHz clock harmonics as markers. Tune to N+10 kHz, then N+30 kHz, and if the tone moves by exactly 20 kHz it's real RF and the synth is locked. Every step from 120 to 2720 MHz tracked except 2440, which was just buried in wifi. Below 100 MHz image cal fails and you get nothing. 100 MHz works (still flags IMG_CAL but tracks). 2740 MHz works, and at 2756 and up the PLL won't lock. So that gets you the top of FM broadcast, all of airband, the 1 to 1.5 GHz gap, and 2.5 to 2.7 GHz. Keep in mind these are leakage markers, so this proves the chain works there, not how sensitive it is. Also one board, one antenna. Your module might be different.

Sample rate tops out at 250 ksps. The I/Q rate is 4x whatever LoRa bandwidth you set. 125k and 250k are clean. 500k overflows the FIFO in about 2 ms and 1M in under 1 ms. That's not really the chip's fault, 500 ksps of 16 bit pairs is 2 MB/s which is the entire 16 MHz SPI bus before overhead. A tighter read loop or a narrower sample format (if the ROM has one) might push it. I've done 6+ minute runs at 125k with zero loss, haven't done long runs at 250k yet.

For gain I ran a weak HackRF carrier at 433.92 and stepped through manual gain. Steps 1 to 5 see nothing, 12 or 13 is where you want to be, boost adds maybe a dB. Chip AGC matches step 13 on weak signals but was about 20 dB worse SNR on a strong one, so a host side AGC picking a fixed step would beat it. Image rejection came out around 41 dB.

BLE works natively. The chip has its own Bluetooth LE packet engine and I hadn't touched it until now. Set it up for LE 1M on the advertising channels and it just started pulling ads. About 500 to 800 valid packets in 10 to 12 seconds per channel, 24 to 32 distinct devices. Coded and 2M heard nothing but nothing nearby was using them, so those are untested, not broken. There's also 802.15.4 (Zigbee/Thread), FLRC, wM-Bus and LoRa ranging in there that I haven't tried yet.

Repo has the probe tools, raw CSVs and the method if anyone wants to reproduce on their board. Would really like to know if other LR2021 modules hit the same edges.

Features

• 📡 Automatic scanning: hops across your frequency ranges (118–137 MHz by default) and stays on a range while someone is talking.
• 🎙️ Records every call: each transmission is saved on its own, with a short pre-roll so the first word isn't cut off.
• 🗣️ Voice detection: a built-in speech detector separates real voice from data bursts, dead carriers, tones and noise.
• 🎧 Play in the browser: click a waveform to seek, or turn on auto-play for new calls.
• 💾 MP3 and WAV: voice calls are saved as MP3 automatically; any recording can be downloaded as MP3 or WAV.
• 🌈 Spectrum page: live spectrum, waterfall and activity history, plus a spectrogram of every signal that was not recognised as voice.
• ✈️ Voice only: ACARS and VDL2 data channels are ignored by default.
• ⚙️ Web settings: device, gain, ranges, thresholds and MP3 options, all from the browser.
• 🖥️ Single native program: C++17, no Python, runs as a desktop app or headless server on Windows and Linux; open it from any phone or PC on your network.