Comparison

ST vs SDR

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

ST

This app converts photos and images into a format compatible with D-STAR transceivers for the Share Picture function. Users can crop images, add text like call signs, and transfer them wirelessly or via Bluetooth to supported transceivers.

Highlights
  • Image conversion for D-STAR Share Picture
  • Image cropping
  • Add text (call signs)
  • Wireless transfer to transceiver
  • Bluetooth transfer to transceiver
  • Save cropped image as file
Features
Read full description

The ST-4001I is an application to crop an image used for the Share Picture function of a D-STAR transceiver, and transfers it to the transceiver. ・Photos taken, or photos/images saved on the iPhone and iPad can be converted into the format used for the Share Picture function of the D-STAR transceiver. ・You can crop the image and enter text such as a call sign. ・The cropped image can be transferred through a network to the D-STAR transceiver. ・The cropped image can be transferred through a network or using Bluetooth to the D-STAR transceiver. ・You can also save the cropped image as a file. Refer to the INSTRUCTIONS for details. Device requirements: iOS12 or later Supported transceiver (As of July 2024) Transceivers that can transfer via Bluetooth Icom ID-52A/E Icom ID-52A/E PLUS Transceivers that can transfer via network Icom IC-705 Icom IC-905 Icom IC-9700* *Firmware version 1.20 or higher NOTE • Icom does not guarantee that the ST-4001I works on all iPhone and iPad. It may not work properly, depending on the OS version, installed applications, or other reasons. • The transceiver and iPhone and iPad must be connected to the same network to transfer an image to a transceiver through a network. • Bluetooth LE is used to connect to a transceiver using Bluetooth. Transferring an image may take some time due to a slow data transfer rate.

About

SDR

Control your Icom transceiver remotely or locally from your iPhone. Operate in all modes, log QSOs, and utilize integrated digital modes like FT8/FT4 and SSTV. No extra hardware is needed for global access.

Highlights
  • Remote transceiver operation
  • All mode control
  • Auto logging logbook
  • Integrated FT8/FT4 tool
  • Integrated SSTV receiver
  • Integrated CW decoder and keyer
  • DX-Cluster integration
Read full description

Your Icom radio on your iPhone: at home over Wi-Fi or from anywhere over the internet. Made by a ham, for hams, with personal support included. SDR-Control Mobile shows the spectrum scope and waterfall of your Icom radio with all its controls. No extra hardware or software needed. WORKS WITH ■ IC-705 (Wi-Fi) ■ IC-7610, IC-7760, IC-9700, IC-7300 MK2 and the IC-R8600 receiver (radio on your network by cable) The app connects over the network only. The older IC-7300 (without MK2) has no network connection and can't be used. OPERATE ■ Spectrum scope and waterfall with band plan, DX Cluster and FT8 spots ■ Two VFOs, filters, preamp, attenuator, NB, NR, notch, AGC and more ■ Compact floating panels: tuning, PTT, CW, memories, macros, Command Bar, DTMF, RIT / ∆TX, D-Star ■ Your iPhone as microphone and speaker; the radio keeps playing in the background ■ Ready for iPhone Duo: the iPhone screens when folded, the large radio screen when open MODES ■ FT8-Improved with AutoAnswer and AutoCQ, plus the classic FT8 ■ JS8 keyboard chat ■ CW with decoder, keyer and CW keyboard ■ Speech: incoming voice transcribed and translated, your typed text sent as speech ■ SSTV, HF-Fax, APRS, WSPR and D-Star FT8-Improved, JS8, Speech and WSPR need iOS 26. TOOLS ■ Logbook with ADIF import and export, shared via iCloud with SmartSDR, FT-Control, TS-Control and K4-Control, on iPhone, iPad and Mac ■ DX Cluster, POTA, PSK Reporter, Call Lookup, Band Plan, Network Stats, Memories, Scanning ■ Controllers: MIDI, CTR2, HaliKey, Pryme, Flic ■ 4O3A Genius devices and Ultra Beam antennas MADE BY A HAM Made by Marcus, DL8MRE, who has been developing apps for Apple devices since 2009 and uses this app every day in his own shack, where all supported radios are on the desk. Personal online support and a detailed manual are included. Updates with new modes and features are free: no subscription, no in-app purchases. WHAT YOU NEED ■ One of the radios above, connected to your network ■ An iPhone with iOS 18 or later ■ For use over the internet: access to your home network from outside (see the manual) Manual: https://go-to.me/sdrcontrol-mobile-manual More apps: https://ham-radio-apps.com

Screenshots

ST4 screens
SDR4 screens

Verdict

The call

The clearest difference is price: ST at Free against SDR's $44.99. ST also leads on rating (5.0 vs 4.6) and device support (3 vs 1). SDR's advantage is review sentiment (84% vs 50%) and update cadence (every 2 weeks vs every 27 months). On ads and in-app purchases 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

CostPrice · In-app purchases · Ads · Monetization

ST is free to download; SDR costs $44.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

ST holds the better App Store score, 5.0 against 4.6. That said, the two scores are not equally well evidenced: SDR has 67 ratings behind it against 4, so its average is the more settled of the two. Written reviews complicate that: 50% of ST's written reviews are positive against 84% of SDR's, so the app with the better star average is not the one people write more warmly about.

UpkeepUpdate frequency

ST ships an update every 27 months, SDR every 2 weeks. The most recent releases landed on October 24, 2026 and October 27, 2026 respectively.

Scorecard8 real differences · 2 level
ST versus SDR: the parameters behind the verdict, then further details
ParameterSTSDR
PriceFree — better$44.99
Rating5.0 (4 ratings) — better4.6 (67 ratings)
Positive reviews50.0% of reviews84.3% of reviews — better
Number of ratings467 — better
Update frequencyEvery 27 monthsEvery 2 weeks — better
AdsNoNo
In-app purchasesNoNo
MonetizationFree — betterPaid
DevicesiPhone, iPad, iPod — betteriPhone
Requires iOS12.0 — better17.6
Further details — not scored
Size12 MB55 MB
Age rating4+4+
DeveloperICOM INCORPORATEDMarcus Roskosch

Customer experience

ST

All ratings2 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews2 reviews
Positive50.0%
Neutral0.0%
Negative50.0%

SDR

All ratings67 ratings
Positive89.6%
Neutral0.0%
Negative10.4%
Written reviews70 reviews
Positive84.3%
Neutral5.7%
Negative10.0%

Bugs and requests

ST

Not enough reviews yet to summarise bugs or requests.

SDR

Reported bugs

12 issues
  • Dialogs do not scale with larger text setting
  • Frequency display overlaps buttons
  • FT8 decoding issues (lower signal levels than WSJTX)
  • App crashes and leaves radio in transmit
  • Logbook export not functional after update
Show 7 more
  • Function button for horizontal scrolling not fully displayed
  • FT8 decode is useless and unreliable
  • Messed up radio, requiring reset
  • RX audio unusable outside home network (prior to 1.5.1)
  • Struggles with audio RX packets on remote cellular networks
  • Cannot work over mobile data with certain carriers (EE)
  • FT8 alerts sound but don't display

Requested features

14 requests
  • Develop for IC-7800
  • CarPlay support
  • Apple Watch add-on
  • Windows version
  • JS8call support
Show 9 more
  • More digital modes
  • Display memory bank names
  • Initiate memory scan from app
  • WSPR implementation
  • Tool for WSPR
  • More FT8/FT4 features (e.g., setting transmit frequency directly in FT8 view)
  • Send image to unit
  • KISS TNC support
  • Control digital modes (reflectors, etc.)

In-app purchases

None

ST

No in-app purchases

None

SDR

No in-app purchases

Questions

Is ST free?
ST is free to download, with no in-app purchases.
Is SDR free?
SDR costs $44.99, with no in-app purchases.
Which has better reviews, ST or SDR?
ST is rated higher. ST averages 5.0 out of 5 from 4 ratings, while SDR averages 4.6 from 67 ratings.
Do ST or SDR have ads?
Neither ST nor SDR shows ads.
Which is updated more often, ST or SDR?
ST ships an update every 27 months, and SDR every 2 weeks. Most recently, ST was updated on October 24, 2026 and SDR on October 27, 2026.

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