Thank you to Ivan (LU8MIL) from the ‘Radio Bunker’ YouTube channel for writing in and sharing ESPica32, a standalone ESP32-based radio that tunes into any public KiwiSDR in the world with no PC or phone needed. The name is a tribute to the Spica, a pocket transistor radio that was hugely popular in Argentina.
The build uses just four parts: an ESP32-WROOM-32, an SH1106 OLED display, a rotary encoder, and a MAX98357A I2S amplifier with a small speaker. A single encoder controls frequency, volume and mode (LSB, USB, AM, CW and FM). A web page served by the ESP32 handles Wi-Fi setup, KiwiSDR server selection and full remote control, and also includes a diagnostic for tracking down audio dropouts.
Ivan notes that distant KiwiSDRs initially cut out because the ESP32 couldn’t keep up with uncompressed audio. Switching to the KiwiSDR’s ADPCM compression fixed this, and a Kiwi in Argentina now plays cleanly from Germany at about 260 ms ping. The Arduino IDE sketch and wiring diagram are available on Ivan’s Todo-SDR blog, and the Spanish-language video below shows the build and a demo (English subtitles are available).
🎯 EL PROYECTO DIY QUE TODO RADIOESCUCHA DEBERÍA CONOCER: ESPica32
Back in July, we posted about Demod, an iOS and iPadOS SDR receiver app that works as a client for rtl_tcp, SpyServer, and KiwiSDR. The developer, Alphonse, recently wrote in again to share updates. Alphonse writes:
Since the launch, Demod has added:
OpenWebRX support on top of KiwiSDR, SpyServer and rtl_tcp. Public receivers are browsable on a built-in map, so it can be tried without any hardware.
FT8, CW and RTTY decoding on the phone.
Identify. Tap an unknown signal and it measures it, checks the shortwave broadcast schedules against the receiver's location and the time, and names the likely station and how far away it is.
Live on-device transcription and translation of what you're listening to.
CarPlay, and a "car radio" Seek that jumps to the next real signal for the current mode and stops there (the next AM station, SSB voice or CW signal). It also works from headphones and the steering wheel.
A band scanner, recording and 15-second rewind of live radio, and Siri ("Tune Demod", "Ask Demod what this signal is").
A three-pane iPad layout, a mains-hum filter, an auto-contrast waterfall and squelch that works on every source.
Android: Demod is now on Google Play, with the same receiver support and decoders. Android Auto support coming soon.
Alphonse has also decided to share with the community 15 free codes for each platform that let you download the app for free. These codes are first come, first served, so if a code no longer works, it will have already been claimed.
iOS (iPhone/iPad) — redeem in the App Store app: tap your profile photo → Redeem Gift Card or Code. Or tap the link directly:https://apps.apple.com/redeem?ctx=offercodes&id=6782193839&code=CODE1 KTKAWEXFT36F, LWPN4RNLTFMK, HMJKF39KLPN9, FM7JEHP7H7XA, 3F9PALW93KYM, MJ7TH3E9E3W9 ,P7P3NJR66XKT, K7WKYKNNRPMY, 94WLYNRLKNFR, 4XE7WAYHX4PN, 3KLPHAE9TTHX, MY64T9JWW3HA ,TXWWHNPMNYAX, LPJALTHR966K, EMRLANKKF7L6
Android — redeem in the Play Store app: profile icon → Payments & subscriptions → Redeem code. Or tap the link: https://play.google.com/redeem?code=CODE1 3SD4H680XKNUGNP9V6SXT8U, 68XKMWQEGUXLW2T6W41XEUR, 2N8E2KY22V9L49D92NQ86DX, VHG4UJPUJ6DGRVZGYGA331Z, 3N48JPPJ8F5RUA9S2E55C2N, 7N4BMSA3X1J893QQGC9H6ZM, VVQBLBGFBJED9GU7Y3UZQZK, NTC82UE8KT1RMSFF9GW1LVA, LBLKS33KUG3PQML1KYVK2P2, 9THCT76YXV61HAFK9ZY22J7, CMF62T6LA46V6PVCUZ4BYZG, S895G4U1E5FZ3QZA255FPU1, QQR944S4BUCA1XKCEBAJPPU, PDYWFXGWUJBV9C9UACTJ065, EXZRMG3RB3XJUEB42Z6KTZH
Back in April we posted about the release of Echo, a free iOS app designed for browsing global web-based KiwiSDR, OpenWebRX, WebSDR, and FM-DX software-defined radios. Mark, the developer of Echo, has written in to us again and wanted to share news about the release of the Pro (paid) version of Echo.
Echo Pro adds several features such as recording, on-device transcription and translation, iCloud sync, and the ability to access recordings across Apple devices. The transcription and translation service may be quite interesting, as it allows you to record an entire foreign radio program to text, and translate it to your language for later reading.
Echo Pro costs either US$4.99/month or US$39.99/year. More information about the app is available at echosdr.com.
Thank you to Val (LZ2XA) for writing in and sharing with us a program he's created called "Cat2Web," which is designed to keep a ham transceiver and a public browser SDR, such as a KiwiSDR tuned to the same frequency and mode, in both directions. This is useful for amateur radio operators, as they could easily determine if their signal is being heard by a distant public remote SDR station.
Cat2Web (C2W) is a small Windows app that keeps a ham transceiver and a public browser SDR — WebSDR, KiwiSDR, OpenWebRX/OWRX+ — tuned to the same frequency and mode, in both directions.
Besides standard CAT (via OmniRig), it controls FlexRadio 6000/8000 directly over the network (SmartSDR TCP, no CAT cable) and SunSDR via TCI, and it can pull a SpyServer/Airspy stream and demodulate it itself. It also lets you pick the audio output device for the SDR sound, and stores a frequency offset per bookmark.
We note that the program is not open source and has a €20 lifetime license price tag attached to it. However, a demo is available with full sync, but limited bookmarks.
Thank you to Muayyad for sharing news about the release of his iPad/iPhone-compatible application, 'DXLens', designed for listening to remote shortwave SDR receivers. DXLens also comes with features like aggregated shortwave schedules from multiple sources, and propagation data and reception forecasting to help users choose the right global receiver for the conditions. He writes:
DXLens is a newly released iPhone/iPad application built around connecting the shortwave schedule and SDR listening workflows.
A listener can begin with a broadcast from EiBi, Aoki/NDXC, or HFCC, inspect the schedule-source evidence and transmission path, review modeled propagation context and assumptions, and then request compatible public SDR receivers for the frequency.
From there, DXLens provides a native listening workspace with live spectrum and waterfall, frequency/mode/bandwidth controls, receiver switching and reconnection, SDR presets, signal/session information, and local recording.
The app also includes Path Atlas, ionospheric and space-weather context, RF Environment tools, Model Audit, alerts, Custom listening views, and a structured reception logbook.
An important design boundary is that scheduled activity, propagation modeling, public receiver availability, and actual reception are kept separate rather than being presented as equivalent evidence.
The app appears to connect to the KiwiSDR network, and also has support for personal rtl_tcp based receivers.
At the moment, the app appears to be free, with no in-app purchases. DXLens is available on the Apple App Store.
Thank you to 'Radio Silence Dev' for writing in and sharing the beta release of his iOS native app, Radio Silence, designed for listening to public KiwiSDR receivers around the world on an iPhone or iPad.
The app streams live audio from the KiwiSDR network, with a live directory showing each node's signal quality, load, and online status. If a receiver drops out mid-session, the app will automatically fail over to another one. There is also a tap-to-tune live spectrum waterfall.
Radio Silence also includes CW, RTTY and FT8 decoders, which all run on-device rather than on the receiver, printing text under the dial as it comes in. Audio keeps playing with the screen locked, and captures are saved to a logbook tagged with frequency, mode, node, S-meter reading and UTC timestamp, with export to ADIF, CSV and WAV. Captures can also be shared as QSL-style reception report cards stamped with the solar flux and Kp index at the time of the catch. NAVTEX and SSTV decoders are in development.
The developer notes that the app is written to be a good citizen on the KiwiSDR network, releasing its channel slot when listening stops and handing it back automatically if playback is left running unattended. Streaming uses about 22 MB per hour.
Radio Silence is free during the beta, and listening is set to remain free at launch, with any future subscription covering software features only. Beta invites can be requested via radiosilencesdr.com.
Radio Silence: Waterfall ViewRadio Silence: Decoding FT8
Back in June, we posted about VibeSDR, an AI vibecoded free and open-source mobile SDR client for rtl_tcp and UberSDR/KiwiSDR/OpenWebRX servers developed for iOS and Android. Recently, Stuart Carr (Stuey3D) wrote in again to let us know that VibeSDR is now available on the Apple App Store for £2.99 and is soon to be available on the Android Play Store too.
In terms of updates, Stuart also notes that he's now developed VibeServer, which provides a more network-efficient way to share RTL-SDRs remotely via an Android phone. VibeServer compresses the data and transfers it at 120KB/s instead of the full 4.8MB/s required by rtl_tcp.
Stuart has also developed an Apple Watch Buddy app version of VibeSDR which runs directly on an Apple Watch, allowing you to view and listen to the spectrum on your wrist. The watch version is still in beta, but Stuart notes that you can join the free beta on TestFlight.
Finally, Stuart has provided us with 20 free promo codes to give away for the Apple App Store version of VibeSDR. To win a promo code, simply comment on this post (making sure to enter an email in the email field), reply to the X post, or comment on the Facebook Post (note that for Facebook you must montior your comment for a reply as Facebook does not allow private messages).
Update: All promo codes have now been allocated, thanks!
AI-Disclaimer: This software was vibecoded with Claude.
VibeSDR Running on an Apple Watch
Introducing VibeSDR Jr: A full SDR Client on your wrist.
Thank you to Alphonse Romero for submitting news about the release of his new iOS and iPadOS SDR receiver app called Demod. Demod is a network client that connects to remote SDR servers, so it can be tried out immediately with no dongle needed at all.
The app works as a client for rtl_tcp, SpyServer (Airspy and RTL-SDR), and KiwiSDR, all in a single app. It features a Metal-accelerated waterfall and spectrum display, AM/NFM/WFM/USB/LSB/CW demodulation, and adjustable bandwidth, gain, and squelch. Other features include frequency memories with CSV import and export, AirPlay and Lock Screen controls, and native layouts for both iPhone and iPad. It can also browse and connect to public SpyServers directly from within the app, which is how it can be used with no hardware of your own. The developer notes that it collects no data, with no ads or tracking.
Alphose writes that Demod is a solo project and is available on the US App Store for US$9.99. More information and screenshots can be found on the project website, and the app itself is available on the App Store.
The developer has also provided us with 15 free codes that we will be giving away in one week. To enter the giveaway, simply comment on this post (make sure to include your email address in the comment so that we can send you the code), the X post, or the Facebook post. (UPDATE: ALL CODES HAVE BEEN ALLOCATED NOW, THANKS!)
