Rustyaxe’s code, including #ham #radio #communications software
on 02026-09-22very nice Wikipedia article about #electronics #communications #history
on 02026-08-25another review of the #JS8Call #radio #communications #protocols.
on 02026-07-28#PDF of the #FCC’s antepenultimate NOUO from March 25. This one is quite a bit spicier than the Jack Gerritsen and Conifer Communications ones: “The Federal Communications Commission (FCC or Commission) received a complaint from Allegheny County Pennsylvania Emergency Services (Allegheny County) concerning interference to its 911 emergency communications channel operating on 470.4375 MHz in Pittsburgh, Pennsylvania. On July 30, 2025, Agents from the Columbia Office of the FCC’s Enforcement Bureau (Agents) conducted an investigation and determined, using direction finding techniques, that the source of the interference to the Allegheny County system was a signal emanating from the residence of David O. Knudtson (Knudtson), licensee of amateur radio station KD3ASC. After the Agents notified Knudtson of the interference issue, he produced a handheld radio (identified as a BTech UV-Pro). An examination of the radio determined that it had been modified to monitor the Allegheny County channel, and its “Audio Relay” feature had been activated. This feature turned Knudtson’s radio into a simplex repeater that was retransmitting the Allegheny County channel. Knudtson surrendered the radio to the Agents. Subsequently, the Agents verified that the interference to the Allegheny County system had ceased.” #communications #RF #radio #law
on 02026-06-02#PDF of the #FCC’s penultimate NOUO (“notice of unlicensed operation”), from April 1, to Conifer Communications: “The San Francisco Office of the Federal Communications Commission’s (Commission’s) Enforcement Bureau has received a complaint of an unlicensed radio station operating on frequency 10.915 GHz located in Moccasin Peak, California. On September 24, 2025, Agents from San Francisco Office confirmed during an on-scene investigation that Conifer Communications was transmitting on 10.915 GHz from Moccasin Peak, California, with a license that had expired on February 12, 2024, and was not renewed.” #communications #RF #radio #law
on 02026-06-02#PDF of one of the three “notices of illegal pirate radio broadcasting” (NIPRBs) the #FCC issued in April. #communications #RF #law #radio
on 02026-06-02Blog of #FCC enforcement actions, including the Jack Gerritsen Notice of Unlicensed Operation, which seems to be the only NOUO they’ve issued since April 1, when they issued another one. Also they issued three NIPRBs in April (“pirate radio” notices, similar to NOUOs), but two of them seem to have been about two #radio stations in Jamaica, New York, on 90.1MHz and 91.9MHz. #communications #RF #law
on 02026-06-02#PDF #FCC “Notice of Unlicensed Operation” on a #ham #radio band, addressed to a Jack Gerritsen, responding to “multiple complaints from licensees in the amateur radio service concerning an unlicensed radio station operating on 146.415 MHz in Los Angeles, #California and causing harmful interference to licensed operators in the amateur radio bands.” I’m curious whether there’s a public list of all of these? #communications #RF
on 02026-06-02#video on using LEDs as light sensors with the #CH32V003 opamp for visible-light over-the-air updates for his badge. #electronics #hardware #communications
on 02026-05-24IP65-rated card-sized (85 × 65 × 6.5mm, 32g) #Meshtastic #LoRa node #hardware for #RFID tracking with #GPS over kilometers, “SenseCAP Card Tracker T1000-E”. #Pricing of US$39.90. Rechargeable 700mAh battery. Uses “global ISM bands in the 863-928 MHz range”. #electronics #radio #communications
on 02026-04-16in the “power-limited regime” of the Shannon–Hartley channel capacity C = B lg (1 + S/N) bits per second, ln(1 + S/N) ≈ S/N because S/N is very small. Consequently C ≈ B S/N/ln 2 = B 1.44 S/N, 1.44 bits per second per hertz times the signal-to-noise ratio, so if you have additive white noise (whose power is proportional to bandwidth B) your channel capacity is independent of the signal bandwidth for fixed signal power. You start to lose power efficiency once you cram your transmit power into such a narrow bandwidth that ln(1 + S/N) stops being a good approximation to S/N. When S/N = ¼ (-6dB) you’re still getting 89% power efficiency, which rises to 95% at -10dB. #communications #math
on 02026-01-16#HN debate on, nominally, whether #Briar is useful in #Iran during the current internet #censorshp blackout, but mostly about random other topics related to #decentralization of #communications such as Meshtastic and Bitchat
on 02026-01-16#video #toread by Tim Hunkin on the Secret Life of the #Radio. #electronics #communications
on 02025-12-12public-domain #video from 01944 explaining FM #radio with a simple tank-circuit transmitter (Hartley oscillator?) with a capacitive microphone in parallel with the tuning cap. His example is 40MHz with a ±40kHz max deviation (80kHz swing), which he says is the Army’s maximum deviation, plus a 10kHz guard band on each size. But in reality they used “reactance tubes” and phase modulation rather than capacitive mics for their transmitters. He says the key difference for an FM receiver is amplitude limiting (a “limiter”), plus of course FM demodulation itself, with a “discriminator”. The limiter is a vacuum-tube device that might have a transistor analogue. The discriminator is a tank, a diode, and a (bypassed) load resistor, tuned so that the “rest frequency” is at the steepest part of the tank’s Gaussian response, so basically you’re just turning FM back into AM and demodulating the AM. #electronics #history #radio #RF #communications
on 02025-12-12#video #toread about common-base amplifier design in #electronics #hardware for #RF #communications
on 02025-10-14#50-things to do with an #RTL-SDR #SDR, mostly using SDR++. #DSP #communications #toread
on 02025-10-10“The Russian Meteor-M orbiting satellites (there are two of them) have fair resolution and broadcast at 137.9 MHz with a signal strong enough to capture with a simple QFH antenna (fixed, omnidirectional) that you can easily build yourself. Their camera scans like a raster and transmits real time images as it passes overhead. The free SatDump software works fine for decoding.” #space #radio #communications
on 02025-08-27electrically long and short #antennas and loading coils and whatnot. #electronics #communications #radio
on 02025-08-24a really comprehensive artice about 1-bit #DACs and #sigma-delta modulation. #DSP #communications
on 02025-08-13#CNLohr #video of an #ESP8266 generating a #bitbang #NTSC signal modulated to 61.25MHz so his TV can receive it. #toread #communications
on 02025-08-12#video on Nordic RF #communications #electronics that can feasibly run off some largish photodiodes used as solar cells. “Ultra low power energy harvester from BPW34. Super small and durable power supply for wireless nodes” on hackaday. Also “Solar-powered flashing LED heart pendant PCB coil” by bobricius in 02018. This guy, "Pocket Concepts", got 300mV out of his BPW34 photodiodes, and used it to transmit a temperature datum over #Bluetooth #BLE to his motherfucking phone. His #Nordic chip uses about 50μC of charge (over the 2.25V to 3.6V range) to run for the necessary 20ms, so he needed 37μF, which looks like maybe it’s a tantalum cap. It gets enough power from his fridge light to send a transmission every few seconds (so, say, 0.4% duty cycle, so he’s getting tens of microwatts). But a slightly larger amorphous cell is even better because it works even in a dimly lit room. #electronics #solar #photovoltaic #energy-harvesting
on 02025-08-09#JS8 is a digital #radio #communications mode derived from #FT8; "JS8call" is GPLv3 software for it derived from WSJT-X. “Jordan Sherer designed 8-FSK modulation”. For #QRP. Super low bandwidth.
on 02025-06-12#USA regulator FCC permitting ultra-low power (whatever that is) on a 1GHz wide band in #6GHz #radio #communications
on 02024-12-13discussion of #USA regulator FCC permitting ultra-low power (whatever that is) on a 1GHz wide band in #6GHz #radio #communications
on 02024-12-13