Comparison

DigiDecoder vs RF Calc JP

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

Head to head
About

DigiDecoder

This application decodes and encodes various ham radio digital modes in real-time. It automatically recognizes signals, displays them with an animated waterfall, and supports sending SSTV images, CW, FT8, and Packet messages.

Highlights
  • Real-time digital mode decoding
  • Automatic signal recognition
  • Animated waterfall display
  • SSTV image encoding
  • CW, FT8, and Packet message encoding
  • Bluetooth and network TNC support
Read full description

DigiDecoder is a universal ham radio digital modes decoder and encoder. Use the built-in microphone or connect an audio cable directly for better input quality. One app for all the signals! The correct digital mode is automatically recognized and decoded in real time with an animated waterfall display. Quickly encode and send beautiful SSTV images, plus CW, FT8, and Packet messages. Bluetooth and network TNCs for Packet are supported as well. Try DigiDecoder free for 7 days. After the trial, continue with an affordable monthly subscription, or unlock lifetime access with a one-time purchase (a few months' worth). Nothing is charged during the trial and you can cancel anytime. Currently supported modes (more to come): SSTV: Robot 8 BW - 160×120 Robot 12 BW - 160×120 Robot 24 Color - 160×120 YCrCb Robot 24 BW - 320×240 Robot 36 - 320×240 YCrCb Robot 72 - 320×240 YCrCb Scottie S1 - 320×256 RGB Scottie S2 - 320×256 RGB Scottie DX - 320×256 RGB Martin M1 - 320×256 RGB Martin M2 - 320×256 RGB PD50 - 320×256 YCrCb PD90 - 320×256 YCrCb PD120 - 640×496 YCrCb PD180 - 640×496 YCrCb PD240 - 640×496 YCrCb PD160 - 512×400 YCrCb PD290 - 800×616 YCrCb Packet: AX.25 1200 - AFSK Bell 202, 1200/2200 Hz FX.25 1200 - AX.25 + Reed-Solomon FEC AX.25 300 - AFSK 1600/1800 Hz FX.25 300 - AX.25 300 + Reed-Solomon FEC IL2P 1200 AFSK - Bell 202 + RS FEC IL2P 300 AFSK - 1600/1800 Hz + RS FEC IL2P 300 BPSK - 1500 Hz DBPSK + RS FEC Weak Signal: FT8 - 8-tone GFSK, 15s periods FT4 - 4-tone GFSK, 7.5s periods JS8 - Keyboard-to-keyboard, FT8-based modulation WSPR - 4-FSK beacons, 2 min periods Narrowband: RTTY - 45.45/50/75 Bd CW/Morse - 5-55 WPM Olivia - 8/250, 8/500, 16/500, 16/1000, 32/1000 Voice: RADE - neural OFDM digital voice Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

About

RF Calc JP

Features
Read full description

RF Calc JP is a practical calculator for amateur radio and RF work, for iPhone and iPad. Its signature feature: apply gains and losses (dB) to an absolute power value (W, mW, dBm …) in sequence — follow a signal from the transmitter through cable loss and amplifier gain to the final output, right on the keypad. KEY FEATURE: MIX ABSOLUTE VALUES WITH dB Enter "1 W − 3.8 dB" and it instantly shows 26.2 dBm (= 0.4169 W = 416.9 mW). Working with absolute values (W/dBm) and relative values (dB) in a single line matches how you actually reason about a link. FEATURES • Power / dBm: convert among W / mW / µW / nW / dBm / dBW. Enter one value and see the rest at once (e.g., 1 W = 1000 mW = 30 dBm = 0 dBW). • RF Chain: start from an absolute power, then stack each stage's gain (+dB) or loss (−dB): TX output → cable loss → amplifier gain → final output. See every stage and name each one. • Voltage: convert among V / mV / µV / nV and dBV / dBmV / dBµV. Set an impedance (default 50 Ω; 75/600 Ω or custom) to convert to power/dBm. Choose RMS / Peak / Peak-to-Peak as the reference. • Unit Converter: convert power and voltage units together, showing multiple units at once. • dB Converter: convert between dB and power/voltage ratios (e.g., +3 dB → power ratio ≈1.9953 / voltage ratio ≈1.4125). • VSWR: convert among VSWR, reflection coefficient |Γ|, return loss, reflected power (%), and mismatch loss. • Power Efficiency: transmitter efficiency from DC voltage, current and RF output (e.g., 13.8 V × 20 A with 100 W RF → about 36.2%). Reverse modes give the required DC current or the expected RF output. BUILT RIGHT • All internal math is double precision and is never rounded mid-calculation — rounding happens only for display, so chained calculations stay accurate. • Results appear in several related units at once. Set the number of digits and engineering (SI-prefix) notation in Settings. • Save a calculation history on device to review later. • Each calculator keeps its input when you switch. Attenuator (ATT) correction and large text sizes (Dynamic Type) are supported. WHO IT'S FOR • Anyone building a quick link budget from the rig to the antenna • Moving between voltage and power (dBm) • Converting VSWR and return loss without mental math • RF and electronics work that lives in dB and gain PRIVACY RF Calc JP collects no personal data and does no tracking. It runs fully offline with no account. Your calculation history is stored only on your device. SUBSCRIPTION All features are available via an auto-renewing subscription (¥200/year in Japan; equivalent local pricing elsewhere), with a 7-day free trial. Cancel at least 24 hours before the trial ends to avoid charges. Manage or cancel anytime in Settings > Apple ID > Subscriptions. A simple, accurate RF calculator for everyday operating and design. Feedback is welcome. 73! ■ Terms & Privacy Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://jpanhamlogapp.github.io/rfcalcjp/privacy.html

Screenshots

DigiDecoder4 screens
RF Calc JP4 screens

Verdict

The call

The clearest difference is iOS requirement: DigiDecoder at 17.0 against RF Calc JP's 26.0. On price, update cadence, 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

Both are free to download. DigiDecoder sells 3 in-app purchases, starting at $2.99 per month and RF Calc JP sells 1 in-app purchase, starting at $0.99 per year. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

Both ship on a similar rhythm, roughly every 6 days. The most recent releases landed on October 28, 2026 and October 24, 2026 respectively.

Scorecard1 real difference · 9 level
DigiDecoder versus RF Calc JP: the parameters behind the verdict, then further details
ParameterDigiDecoderRF Calc JP
PriceFreeFree
Rating4.5 (8 ratings) — better—
Positive reviews50.0% of reviews—
Number of ratings8 — better—
Update frequencyEvery 6 daysEvery 6 days
AdsNoNo
In-app purchasesYesYes
MonetizationFree with in-app purchases—
DevicesiPhone, iPad, Mac — betteriPhone, iPad
Requires iOS17.0 — better26.0
Further details — not scored
Size16 MB4 MB
Age rating4+4+
DeveloperLukasz SkierkowskiHashimoto Yoshikazu

In-app purchases

3 purchases

DigiDecoder

Subscriptions1
  • DigiDecoder Monthly7 Days trial$2.991 Month
One-time2
  • DigiDecoder TrialFree
  • DigiDecoder Lifetime$8.99
1 purchases

RF Calc JP

Subscriptions1
  • RF Calc JP Pro (Yearly)7 Days trial$0.991 Year

Questions

Is DigiDecoder free?
DigiDecoder is free to download, with in-app purchases available.
Is RF Calc JP free?
RF Calc JP is free to download, with in-app purchases available.
Do DigiDecoder or RF Calc JP have ads?
Neither DigiDecoder nor RF Calc JP shows ads.
Which is updated more often, DigiDecoder or RF Calc JP?
DigiDecoder ships an update every 6 days, and RF Calc JP every 6 days. Most recently, DigiDecoder was updated on October 28, 2026 and RF Calc JP on October 24, 2026.

Other comparisons