Doppler pass insights

The Doppler pass insights tool loads a recorded pass log (CSV) and tells you, in plain language, whether your Adaptive threshold and Lead Doppler settings are working well — and what to change if not. You can also load a second pass to compare settings before and after a tweak.

Opening Doppler pass insights

Go to Menu → Help → Doppler pass insights to open the window.

Loading a pass log

Click Open CSV to browse to any Doppler log file on your computer, or click Load latest to open the most recent log from your local folder. Each row in the CSV records a snapshot or CAT event during the pass.

After loading, start on the Tuning guide tab — that is where the actionable advice lives. The chart and detailed metrics are on other tabs if you want to dig deeper.

Opening the logs folder

On the Files tab, click Open log folder to open your system file browser to the Doppler logs directory. On Windows, logs are stored in %AppData%\OscarWatch\doppler-logs\. OscarWatch keeps Doppler CSV files for 14 days (same window as the main app logs under %AppData%\OscarWatch\logs\). Older CSVs are removed automatically when a new pass log starts, when you load the latest log in this window, or when you open the Doppler logs folder. Copy any CSV you want to keep longer to another folder before that window expires.

Tuning guide tab

This is the main tab. It is designed for radio amateurs who want a clear answer, not a wall of graphs.

Pass headline

Shows the satellite name, pass duration, and peak elevation so you know which pass you are reviewing.

Verdict

A short overall assessment, for example:

Tracking looks good — typical error stayed low; no major changes suggested
Threshold may be too high — too many samples were suppressed; the radio was not corrected often enough
Consider Lead Doppler — fast Doppler slew but lead was off or rarely used
CAT may be too aggressive — write rate very high; tuning may sound choppy
Manual tuning detected — interactive or CAT-paused periods during the pass

Adaptive threshold card

Explains whether adaptive threshold helped near TCA, whether the band was too conservative, or whether you should enable it. Each card ends with a specific suggested action (e.g. lower threshold by 10–20 Hz, or keep adaptive enabled).

Lead Doppler card

Explains whether Lead Doppler kept up during fast legs, was too weak, or was not needed. Suggests changes to lead time or lead strength in Radio settings when appropriate.

Settings recorded for this pass

Pulled from the log file header: linear threshold, CAT delay, adaptive on/off, lead on/off, lead time, and lead strength. Use this to confirm which settings were active when the pass was recorded.

Recommendations

A bullet list of follow-up items based on the pass data (threshold too high/low, enable lead, try adaptive, etc.).

Pass breakdown

The pass is split into stages — AOS (start), rising, TCA vicinity, descending, and LOS (end). For each stage you see downlink tracking error (p95), CAT write rate, peak slew, and max elevation. Use this to see where in the pass a problem occurred: threshold tuning matters more on the approach legs; Lead Doppler matters most near TCA and on the descending leg.

Chart tab

The chart is for visual confirmation once you have read the tuning guide. It shows how tracking error grew and dropped over the pass:

Blue — Downlink tracking error (Hz from calculated Doppler target)
Orange — Uplink tracking error
Teal band — Adaptive threshold zone (effective threshold during fast legs)
Dashed teal line — Base threshold (your configured SSB/CW value)
Purple ticks — CAT corrections (when OscarWatch commanded the radio)
Grey strip below — Satellite elevation over the pass
Amber dashed line — TCA (time of closest approach, highest elevation)

Lines break at each CAT write so you see individual “sawteeth” rather than a tangled web. Smaller, smoother cycles mean better tracking. The vertical axis is labelled Tracking error (Hz); the horizontal axis is elapsed time from pass start.

Zooming and panning

Use the zoom buttons above the chart:

+ — Zoom in (up to 16× magnification)
− — Zoom out
Reset — Return to full-pass view

When zoomed in, scroll horizontally to pan. You can also use Ctrl+scroll wheel to zoom. This helps you inspect the steep middle of a pass or the approach and departure legs.

Analysis tab

Detailed numbers for operators who want the raw metrics:

Overview

Summary — Satellite, pass window, row counts, snapshots, CAT writes, offset changes
Thresholds — Base and effective threshold, adaptive reduction, suppressed row percentage
Dynamics — Average and p95 deltas, peak slew
Activity — RX/TX write rates, interactive rows, CAT paused, lead enabled

Activity bars

Progress bars for RX writes, TX writes, suppressed-by-threshold rows, and manual/interactive periods.

Recent events

A chronological log of sampled points: UTC time, event type, RX/TX deltas, write flags, threshold status, and notes.

Comparing two passes

On the Files tab, click Open compare CSV and load a second pass log (e.g. after changing threshold, adaptive, lead time, or lead strength). OscarWatch will:

Overlay the comparison pass on the chart as dashed lines
Show both passes' metrics in the Comparison tab
Calculate a verdict (better, worse, or mixed)
Suggest the next tuning step

Change one setting at a time, record another pass, then compare — otherwise you will not know which change helped.

Understanding the comparison verdict

The Comparison tab appears once you load a second pass:

Tick (✓) Better — The second pass improved on several metrics: lower p95 deltas with stable write rates.
Cross (×) Worse — The second pass got worse. Consider reverting or trying a different adjustment.
Tilde (~) Mixed — One metric improved, one got worse. Fine-tune further.

Next actions

Lower threshold or CAT delay slightly — More aggression would help
Raise threshold or CAT delay slightly — Reduce write chatter
Keep these settings — Tuning looks solid
Make a small adjustment and compare again — Results inconclusive

Practical tuning workflow

Enable pass logging. In Settings → Radio, turn on Doppler pass log (CSV).
Record a baseline pass. Work a satellite with your current Doppler settings.
Open tuning guide. Menu → Help → Doppler pass insights → Load latest. Read the verdict and Adaptive / Lead cards first.
Make one small change. Adjust threshold by 10–20 Hz, toggle adaptive threshold, or tweak lead time or lead strength — try only one change.
Record a second pass and load both CSVs via Files → Open compare CSV.
Repeat or keep. If the comparison verdict is better, keep or refine. If worse, revert and try a different direction.

Tip: Linear transponders (SSB/CW) reveal tuning differences better than FM cubesats. Steep, fast passes show Doppler effects more clearly than shallow ones. Archive passes you are happy with (rename the CSV) so you can use them as baselines later.

Chart overlay legend (comparison)

Solid lines — Primary pass (first loaded)
Dashed lines — Comparison pass

If dashed lines sit close to solid lines, both passes tracked similarly. Divergence near TCA usually means your settings change affected behaviour on the fast leg.

Exporting and logging

Doppler pass logs are plain CSV files. You can copy them for archiving or open them in a spreadsheet. OscarWatch automatically deletes CSVs older than 14 days; it does not delete recordings or other AppData files. Each filename encodes the satellite and UTC start time, for example: RS-44-26-06-22-13-46-doppler.csv