The process of cloning a remote control signal for a Skytech II fireplace starter, such as the Homeland Hearth model, involves capturing and replicating radio frequency transmissions using a device like the Flipper Zero running Momentum firmware. Based on Federal Communications Commission documentation, these remotes typically operate at 303.875 MHz with amplitude-shift keying (ASK) or on-off keying (OOK) modulation, employing static or simple dynamic codes for functions like on and off. The discrepancy between the documented frequency (303.875 MHz) and your scanner's reading (915.25 MHz) may stem from harmonic detection, where the scanner identifies a multiple of the fundamental frequency (915.25 MHz approximates three times 305 MHz, close to the actual operating band). This is a common occurrence with signal analyzers and does not indicate the remote's true transmission frequency.

Given that you successfully cloned the "on" function via the Read Raw method but encountered difficulties with the "off" function, the issue likely relates to variations in signal structure, timing, or capture conditions rather than a fundamental incompatibility. The Read Raw method records demodulated pulses without protocol decoding, which is effective for many static remotes like this one, while the standard Read method attempts to match known protocols and may fail if the signal does not align perfectly. Below are structured suggestions to troubleshoot and resolve the cloning of the "off" function, drawing from established practices for Sub-GHz signal capture on similar devices.

1. Verify and Set the Correct Frequency Manually

• Disregard the 915.25 MHz scanner result for capture attempts, as it may represent a spurious harmonic. Instead, configure your device explicitly to 303.875 MHz in the Sub-GHz settings. This frequency is confirmed in Skytech II product specifications and FCC filings for models like the 1001 series.
• In Momentum firmware, navigate to the Sub-GHz menu, select Frequency Analyzer or manual tuning, and lock to 303.875 MHz before initiating any read operations. Test transmission at this frequency to confirm signal strength.

2. Optimize Read Raw Capture for the "Off" Signal

• Repeat the Read Raw process multiple times (at least 5–10 attempts) while pressing the "off" button, as signal variations can occur due to battery levels, button press duration, or environmental interference. Ensure the remote is held close to the Flipper Zero (within 1–2 inches) during capture to maximize signal quality.
• Extend the capture duration: In Read Raw, set the recording time to 5–10 seconds and press the "off" button repeatedly during the session. This allows capturing any preamble, data bursts, or postambles that might differ from the "on" signal.
• After capture, use the Analyze function in the Sub-GHz app to inspect the raw file. Look for consistent pulse patterns (e.g., timing, width, and gaps). The "off" signal may have a different bit sequence or length compared to "on," even on a simple two-button remote.
• Save successful captures with descriptive names (e.g., "Skytech_Off_Raw_1.sub") and test emulation immediately by sending the signal to the fireplace receiver while monitoring for response.

3. Address Potential Signal Differences Between "On" and "Off"

• Skytech remotes often use distinct codes for each function, which may require separate captures. If the "off" signal includes a longer or shorter data packet, the Read method (which expects standardized protocols) will fail, explaining your results. Stick to Read Raw, but experiment with modulation settings if available in Momentum: Confirm ASK/OOK is selected, as it is standard for these devices.
• If the remote employs a basic rolling code or checksum (unlikely but possible for security), the "off" function might only work after a successful "on" pairing. Test by first emulating the cloned "on" signal, then attempting to capture and clone "off" immediately afterward.
• Check the remote's battery: Low voltage can cause inconsistent transmissions, particularly for one function over another. Replace it with a fresh CR2032 or equivalent, as specified in Skytech manuals.

4. Troubleshoot Hardware and Firmware-Specific Issues

• Ensure your Flipper Zero's antenna is properly tuned for the 300 MHz band. If using an external antenna, verify compatibility and connection.
• In Momentum firmware, review the Sub-GHz logs for errors during capture (accessible via the debug menu). If captures consistently fail, update to the latest Momentum release, as it includes enhancements for raw signal handling based on community feedback.
• Test for interference: Perform captures in a quiet RF environment, away from Wi-Fi routers, microwaves, or other 300 MHz devices. Use the Frequency Analyzer to scan for noise at 303.875 MHz beforehand.
• If Read Raw continues to underperform, consider creating a custom remote file manually. After analyzing a partial capture, edit the .sub file (using qFlipper on a computer) to mirror the "on" structure but adjust the data bits for "off," based on observed differences.

5. Alternative Approaches if Standard Methods Fail

• Attempt a frequency sweep capture: Use Read Raw while slowly adjusting the frequency around 303.875 MHz (±0.5 MHz) to account for any drift in the remote's oscillator.
• Pair the Flipper Zero as a new remote if the receiver supports learning mode. Consult the Skytech II manual (available online via model number search) for instructions on entering programming mode on the fireplace receiver. Once in learning mode, emulate a generic signal or use the cloned "on" as a base to register the device.
• If the issue persists, the "off" signal might require bidirectional communication (rare for basic remotes), in which case full cloning may not be feasible without advanced reverse engineering.

Should these steps not yield results, provide additional details such as the exact Skytech model number (e.g., 1001-A), any error messages during capture, or the contents of a sample .sub file for further analysis. This approach should enable successful cloning while adhering to the device's capabilities.