iSDR vs ARRL magazines
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
iSDR
This app allows experimenters and amateur radio enthusiasts to build a portable software-defined radio receiver using their iOS device. It processes radio signals using the device's processor and offers various display and filtering modes. Additional hardware is required for live signal reception.
- Six receive mode settings (USB, LSB, CW, AM, FM, Binaural)
- Selectable bandwidth settings
- 120 dB dynamic range signal strength meter
- Three AGC settings (fast, slow, off)
- Spectrum, Waterfall, and Oscilloscope display modes
- Supports downloaded audio-format spectrum files via iTunes
- Embed center frequency in file names for automatic display
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PLEASE READ THE ENTIRE DESCRIPTION BEFORE PURCHASING. iSDR is the first and only software-defined radio application compatible with the Apple iPhone®, iPod touch® and iPad™. iSDR is for experimenters and amateur radio enthusiasts looking to construct a truly portable software-defined radio receiver. Additional hardware is required to receive live signals. Currently, iOS devices will not work with RTL-SDR USB dongles, and they are not supported by iSDR. PLEASE NOTE: Receiving live on-air signals using iSDR requires purchasing or constructing a "quadrature sampling detector (QSD)" RF front-end device, and connecting it between an antenna and the microphone input jack. Alternatively, iSDR can be used to implement a panadapter for use with a compatible radio receiver. Without a QSD RF front-end or a connected radio, iSDR will only play I/Q recordings of actual radio signals. Additional recordings can be loaded into the app using iTunes file sharing - some recordings are available free to download from the Internet. Visit the support web site for more information. iSDR includes a sample I/Q recording featuring 30 seconds of a ham radio contest. This is for demonstration purposes only. It is not meant to fool you! It is to allow you to experience how the app works without having to do anything yourself: just turn it on. You can download and play your own files if you like. Please see the support page for details. AND PLEASE contact us directly if you experience any issues with using this app. We will respond promptly when provided with details. When iSDR is used to receive live radio signals, receiver performance will depend largely on the quadrature sampling detector and antenna that you use. iSDR is a software-defined receiver application for use on mobile handset devices and iPad. Despite its extreme portability, the app utilizes the same digital signal processing techniques found in PC-based SDR receivers. It does frequency domain filtering using a theoretical "brick wall" sinc filter algorithm to provide steep and deep bandpass filtering. iSDR doesn't utilize any DSP hardware but instead uses the iOS device's processor to implement DSP algorithms. Features o Six receive mode settings: USB, LSB, CW, AM, FM* and Binaural. o Selectable bandwidth settings for each mode. o Signal strength meter covering 120 dB of dynamic range with peak and average power indication. o Three AGC settings: fast, slow, and off. o Three display modes: Spectrum, Waterfall and Oscilloscope. o File sharing** supports downloaded audio-format spectrum files synced using iTunes. o Most PCM file formats are supported, including .wav and .caf. o Embed the center frequency in your file names and iSDR will automatically display the correct frequency! o Tune quickly using a single touch to the display screen, or tune precisely using the rainbow tune bar. o Change radio settings with a simple double-tap action to the red cursor, mode text, AGC indicator or signal grid! o Up to 44.1 kHz of available spectrum bandwidth. o Dimmable semi-log or linear spectrum grid (native Settings app only). o Adjustable CW offset (native Settings app only). o Monaural microphone input automatically adjusts the display to 22 kHz bandwidth. o Automatically detects if external audio is available for receiving live signals (menu selectable). o Reverse I/Q stereo input logic (menu selectable). *FM mode is not supported for monaural signals, and will not appear as a mode selection unless stereo audio (live or recorded) is available. Narrowband FM only: 16 kHz or 11.2 kHz bandwidth. Please contact Digital Confections with your questions and suggestions!
ARRL magazines
Access the monthly ARRL membership journal, QST, on your iPhone, iPad, or iPod Touch. This publication offers news, construction projects, and tutorials for Amateur Radio enthusiasts. The digital version includes exclusive content not found in print.
- Monthly QST digital delivery
- News and updates
- Construction projects
- Tutorials and guides
- Exclusive digital content
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If you're a member of ARRL, the national association for Amateur Radio, install this app and have QST, the ARRL membership journal, delivered to your iPhone, iPad or iPod Touch every month! QST entertains and informs with news, construction projects, tutorials and much more. That's why it is the most widely read Amateur Radio publication in the world. The digital version of QST goes even further with content not found in the printed journal. Privacy & Terms of Conditions: http://www.arrl.org/online-privacy-policy
Screenshots
Verdict
The clearest difference is price: ARRL magazines at Free against iSDR's $0.99. ARRL magazines also leads on in-app purchases (none vs 1) and ratings volume (258 vs 11). iSDR's advantage is rating (2.5 vs 1.8) and review sentiment (52% vs 12%). On update cadence, ads and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
ARRL magazines is free to download; iSDR costs $0.99 up front. iSDR sells 1 one-off in-app purchase. ARRL magazines asks for nothing beyond the download.
iSDR holds the better App Store score, 2.5 against 1.8. That said, the two scores are not equally well evidenced: ARRL magazines has 258 ratings behind it against 11, so its average is the more settled of the two. Written reviews point the same way: 52% of iSDR's written reviews are positive against 12% of ARRL magazines's.
iSDR ships an update every 3 months, ARRL magazines every 4 months. The most recent releases landed on October 4, 2026 and October 9, 2026 respectively.
| Parameter | iSDR | ARRL magazines |
|---|---|---|
| Price | $0.99 | Free — better |
| Rating | 2.5 (11 ratings) — better | 1.8 (258 ratings) |
| Positive reviews | 51.7% of reviews — better | 12.2% of reviews |
| Number of ratings | 11 | 258 — better |
| Update frequency | Every 3 months — better | Every 4 months |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Paid | Free — better |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 9.0 — better | 12.0 |
| Further details — not scored | ||
| Size | 36 MB | 126 MB |
| Age rating | 4+ | 4+ |
| Developer | Digital Confections LLC | ARRL, American Radio Relay League, Inc. |
Customer experience
iSDR
ARRL magazines
Bugs and requests
iSDR
Not enough reviews yet to summarise bugs or requests.
ARRL magazines
Reported bugs
3 issues- Downloading issues causes app to freeze
- Inconsistent behavior across devices
- Disappearing downloaded content
Requested features
3 requests- Seamless integration with ARRL account
- Ability to resume reading from last page
- PDF export option
In-app purchases
iSDR
- Wi-Fi Radio ControlFree
ARRL magazines
No in-app purchases







