Feld Hellschreiber vs RS
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Feld Hellschreiber
This app decodes and transmits text messages using the historical Hellschreiber system, which sends characters as audio signals. It's ideal for amateur radio operators and enthusiasts interested in vintage communication methods. The app allows for both manual text entry and pre-set messages, with adjustable display contrast for optimal viewing.
- Decode Hellschreiber messages
- Transmit text messages
- Canned text message support
- Adjustable display contrast
- Real-time text scrolling
- Audio input/output via device mic/speaker
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Hellschreiber is a teleprinter system, developed in the 1920s, that transmits text via sound, much like an old facsimile (fax) system. Each pixel of a character is transmitted as a short burst of audio. It works even under very noisy and poor reception conditions, because your brain does the work of analyzing the received image to pick out the characters. It was used by the German military during World War II to send messages encrypted by ENIGMA machines. Today it is used by amateur (ham) radio operators around the world to send messages to each other via shortwave radio. Feld Hellschreiber literally means "bright field recorder". Hellschreiber is sometimes referred to as simply Hell. Feld Hellschreiber lets you decode and transmit Feld Hell messages. Decoded text is continuously scrolled across the top of the display. You can type in text to transmit, or press a button to easily send canned text messages, such as CQ calls. Sound is picked up from your radio's speaker via the internal mic in your device, and transmitted audio comes out the speaker - you can also connect a patch cable to your radio's mic input via the headphone jack on your device to transmit the audio, if you wish. The slider control adjusts the display contrast, and the indicator to the right shows the volume. Adjust the slider for the best display. To transmit text, touch on the text entry field, and start typing. Each character will be sent when possible. When sent, it will be taken off the left end of this field, and displayed on the right end of the transmitted text field, to the left of the entry field, in a scrolling fashion. Canned text buttons are also available, touch one to send the text stored for that button. To edit a button, touch the Setup button, and then select the button you wish to edit. You can edit the name of the button, as well as the text. To decode transmissions, you just need to run the app, and set it near the radio's speaker or headphones, and watch the decoded text appear. It's that easy!
RS
Control compatible transceivers, share voice and pictures, and view station locations on a map. Access received station information, send text messages, and manage call sign and repeater lists. Customize transceiver and application settings for a streamlined experience.
- Transceiver DR functions
- Send and receive voice and pictures
- Map repeater and station locations
- Read and edit received station information
- Send and receive text messages
- Manage call sign and repeater lists
- Import/Export data
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Functional overview of the application DR functions You can use some transceiver’s DR functions. Share pictures Send and receive voice and pictures. Map See the location of repeater sites or other stations on a map using received position data, or your transceiver’s repeater list. Automatically set the transceiver’s “FROM” and “TO” fields by tapping a repeater site or a station on the map. Receive History In the DV mode, read and edit the received station’s information. Download additional information from an Internet database, such as QRZ.com or APRS.fi. Text messaging Send and receive text messages. Call Sign list Edit call signs and names used in the DR function. Also, you can add a call sign and a name in the Call Sign list. Repeater list See the detailed data entered in the Repeater list. Transceiver settings Change some of the transceiver’s function settings. Application settings Select application software settings. Import Import a Repeater list or a Call Sign list. Export Export a Repeater list, a Call Sign list, or Receive History. See the transceiver’s instruction manual for details. The instruction manual can be downloaded from the ICOM web site. Device requirements The RS-MS1I operating requirements are as follows: iOS16 or later Usable transceivers (As of May 2026) - ID-4100A/E + Bluetooth unit (UT-137) - ID-52A or ID-52E *1 - ID-52A PLUS or ID-52E PLUS *2 - ID-5200A or ID-5200E *3 - IC-705 *4 *1 Supported in RS-MS1I Ver.1.1.0 or later. *2 Supported in RS-MS1I Ver.1.3.0 or later. *3 Supported in RS-MS1I Ver.1.4.0 or later. *4 Supported in RS-MS1I Ver.1.2.0 or later. Preparation To use the RS-MS1I with a supported transceiver, you need an optional Bluetooth unit. See your transceiver’s instruction manual for details. Transceiver’s settings Set the following functions as shown below to use the RS-MS1I. [Function] > [CI-V] > [CI-V Transceive]: ON [Bluetooth Set] > [Data Device Set] > [Serial Port Function]: CI-V (Echo back OFF) Note: - The RS-MS1I may not work with all iPhones or iPads, even if they are one of the tested devices. This is because an application program on your device may conflict with the RS-MS1I. - The RS-MS1I may not be used, depending on the OS version, installed application, and so on. - Bluetooth LE is used for the connection with the transceiver, so there may be a time delay between the transceiver’s operation and the display on the iPhone or iPad. - When sending or receiving pictures using “FAST mode,” the headset audio will be temporarily interrupted because of the transceiver’s Bluetooth unit limitations. - You may need to connect to the Internet through a Wireless LAN, an LTE network or a 5G network for some functions. - The RS-MS1I supports only portrait orientation with the iPhone. It does not support Auto Rotate. However, landscape orientation and Auto Rotate are supported with the iPad.
Screenshots
Verdict
The clearest difference is review sentiment: Feld Hellschreiber at 75% against RS's 15%. Feld Hellschreiber also leads on rating (2.8 vs 1.9) and iOS requirement (6.0 vs 16.0). RS's advantage is price (Free vs $2.99) and ratings volume (76 vs 5). On update cadence, ads, in-app purchases 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
RS is free to download; Feld Hellschreiber costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.
Feld Hellschreiber holds the better App Store score, 2.8 against 1.9. That said, the two scores are not equally well evidenced: RS has 76 ratings behind it against 5, so its average is the more settled of the two. Written reviews point the same way: 75% of Feld Hellschreiber's written reviews are positive against 15% of RS's.
Feld Hellschreiber ships an update every 13 months, RS every 8 months. The most recent releases landed on October 8, 2026 and October 17, 2026 respectively.
| Parameter | Feld Hellschreiber | RS |
|---|---|---|
| Price | $2.99 | Free — better |
| Rating | 2.8 (5 ratings) — better | 1.9 (76 ratings) |
| Positive reviews | 75.0% of reviews — better | 14.7% of reviews |
| Number of ratings | 5 | 76 — better |
| Update frequency | Every 13 months | Every 8 months — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Free — better |
| Devices | iPhone, iPad, iPod — better | iPhone, iPad |
| Requires iOS | 6.0 — better | 16.0 |
| Further details — not scored | ||
| Size | 4 MB | 34 MB |
| Age rating | 4+ | 4+ |
| Developer | Black Cat Systems | ICOM INCORPORATED |
Customer experience
Feld Hellschreiber
RS
Bugs and requests
Feld Hellschreiber
Not enough reviews yet to summarise bugs or requests.
RS
Reported bugs
29 issues- App crashes when using map function
- App crashes on map screen
- App closes when opening map
- Not staying connected to the app
- Connection unsuccessful error message
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- Bluetooth pairing not working
- Connects and immediately disconnects
- Does not download full repeater list
- Bluetooth connection fails
- App crashes when selecting a picture to send
- Photo import force closes app
- App bombing out when trying to add a photo
- Attempting to transfer photos crashes every time
- Cannot get app to pair
- App sees radio but won't connect
- App won't connect
- Cannot connect app to iPhone
- ID-52A not pairing
- App instantly sees device but fails to connect
- Bluetooth connection does not happen
- App crashes trying to share photo
- App picture send capability is INOP
- App force closes / crashes on photo import
- Cannot get it to connect on either device
- App doesn't work with ICOM ID-5100
- App doesn't work with 4100 on iOS 15
- App doesn't work with iPhone 6s+
- Bluetooth connection does not happen after lengthy labours
- App has not been updated in almost a year
Requested features
12 requests- Add support for ID-5100
- Add support for ID-51A Plus 2
- Add support for ID-50
- Add support for IC-705
- Improve repeater list
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- Import repeater lists via Files/OneDrive/Dropbox
- Serial port support via USB
- Add support for ID-4100A with BT module
- Add support for IC-2820
- Update for iOS 15
- Update for iOS 16
- Update for iOS 18
In-app purchases
Feld Hellschreiber
No in-app purchases
RS
No in-app purchases







