RF Path vs iSmith
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
RF Path
Calculate radio frequency propagation loss using various models like Irregular Terrain, Okumura-Hata, and COST-231. Supports area and point-to-point predictions, with results exportable via email or social media.
- Multiple propagation models (Irregular Terrain, Okumura-Hata, COST-231)
- Area Prediction mode
- Point-to-Point prediction mode
- Elevation profile display
- Results export (CSV)
- Save to iCloud
- Share to social media
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RF Path provides propagation loss calculations for radio frequencies (RF) between 20 MHz and 20 GHz using either the Irregular Terrain model, Okumura-Hata model, COST-231 Hata Extension model, or the COST-231 Walfish-Ikegami model. The calculations are based on both electromagnetic theory and the statistical analysis of terrain characteristics to calculate the degradation of the RF wave as a function of distance and the variability of the RF wave with respect to time and space. The Irregular Terrain Model has two different prediction models. One is the Area Prediction mode which calculates propagation losses over an area where the exact terrain parameters are not known, but approximated using terrain roughness, environmental parameters and statistical parameters. The second is a point-to-point mode where specific latitude/longitude pair values are entered for both transmitter and receiver. Environmental parameters and statistical parameters are also used in this prediction mode. The results may be saved to iCloud, emailed, or posted to Facebook or Twitter. The results are in CSV format. In the Area Prediction mode a table along with a graph shows the path loss over the distance entered into the settings. The graph is viewed by rotating the device once the results table is shown. In the Point-To-Point Prediction mode a table along with a graph shows the path loss and elevation profile of the RF path.
iSmith
This app helps users understand impedance matching principles. It allows for reading key network parameters from a Smith chart and calculating various matching networks and pads. Users can also convert between different power and voltage units.
- Read Smith chart parameters (Z, Y, VSWR, Q, Gamma)
- Calculate 8 L-matching networks
- Calculate T & Pi matching pads
- Set matching targets on Smith chart
- Learn impedance matching principles
- dBm, Watts, and Volts conversion
- VSWR conversion
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Features: - Read out Z, Y, VSWR, Q and Gamma from smith chart. - Calculate 8 L-matching networks. - Set matching target by touching smith chart. - Calculate T & Pi matching pad. - Learn the principle of impedance matching. - dBm, Watts and Volts conversion - VSWR Conversion
Screenshots
Verdict
The clearest difference is price: iSmith at Free against RF Path's $2.99. iSmith also leads on rating (5.0 vs 3.5) and update cadence (every 2 days vs every 5 months). RF Path's advantage is ads (none vs shown) and chart position (#165 vs unranked). On 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
iSmith is free to download; RF Path costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.
iSmith holds the better App Store score, 5.0 against 3.5. Both are backed by a comparable volume of ratings — 4 and 1 respectively.
RF Path ships an update every 5 months, iSmith every 2 days. The most recent releases landed on September 21, 2026 and June 6, 2026 respectively.
| Parameter | RF Path | iSmith |
|---|---|---|
| Price | $2.99 | Free — better |
| Rating | 3.5 (4 ratings) | 5.0 (1 ratings) — better |
| Positive reviews | 50.0% of reviews | — |
| Number of ratings | 4 — better | 1 |
| Update frequency | Every 5 months | Every 2 days — better |
| Ads | No — better | Yes |
| In-app purchases | No | No |
| Monetization | Paid | Ad-supported — better |
| Best chart rank | #165 — better | — |
| Devices | iPhone, iPad, iPod, Mac — better | iPhone, iPad |
| Requires iOS | 13.0 — better | 16.0 |
| Further details — not scored | ||
| Size | 15 MB | 7 MB |
| Age rating | 4+ | 4+ |
| Developer | Tom Doherty | Ryoun Chon Shin |
Customer experience
RF Path
iSmith
In-app purchases
RF Path
No in-app purchases
iSmith
No in-app purchases









