WSJT-X for field activations

WSJT-X runs FT8, FT4, and related weak-signal modes. For POTA it is a contact engine when propagation or power is marginal — not a replacement for spotting and park references in your log.

Fake it till you make it: do not spend the first activation making WSJT-X into a POTA logger. Run FT8, log QSOs in WSJT-X, keep Polo (or N3FJP) as the master for SSB/CW, then split the files and merge in ADIF Doctor at close-out. Stamp MY_SIG_INFO, explode 2-fers, export the POTA pack, then Recap from Full ADIF.

Sources: POTA digital modes guide · WSJT-X home

Split logs, then Doctor (activation close-out)

WSJT-X’s wsjtx_log.adi is a sitting file, not a pota.app upload. Polo’s POTA export is a different sitting file. Uploading both without merging is how you get dupes, missing parks, and a Recap map with no grids.

Stop WSJT-X. Keep the renamed archive (20250831-us1412-wsjtx.adi) plus Polo Full (grids) and Polo POTA (privacy strip).
Drop Full + WSJT ADIF on ADIF Doctor → merge (physical de-dupe). Stamp call / park / grid if empty.
Explode comma 2-fers if Doctor says so.
Download the POTA pack (no grids) for pota.app. Download Full for Recap / LoTW / AC Log.
Recap → Open Recap with Full (or paste Full). Never feed Recap the POTA export.

Phone-only FT8 (no Polo rows) still needs park tags. Doctor can stamp MY_SIG_INFO on the WSJT file. Confirm a test QSO in a text editor (MY_SIG_INFO, <EOR>) before you trust the first upload.

Before you leave home

Install and update WSJT-X. Back up wsjtx_log.adi.
Fresh log for the activation: stop WSJT-X, rename wsjtx_log.adi to something like 20250831-us1412-wsjtx.adi, restart. WSJT-X creates a clean log so “worked before” reflects this outing only.
Configurations: WSJT-X → File → Save new configuration per vehicle/rig (POTA-truck, POTA-summit). Store rig CAT, audio device, and grid per profile.
Settings → General: callsign, My Grid = this activation’s 6-character Maidenhead (from your field sheet), not home.
Tx macros: add CQ POTA YOURCALL FN31ab (adjust grid) for the Tx #5 slot or custom macros.

Rig and audio

USB audio interface or radio USB — avoid laptop mic/speaker if you can.
USB-D / data mode on the radio. Keep ALC just starting to move; heavy ALC sounds ugly on FT8.
Enable rig CAT in WSJT-X or run FLrig as the rig intermediary if you switch between FLdigi and WSJT-X on one radio.
Split Operation (Settings → Radio): Rig uses the radio’s two VFOs. Fake It has WSJT-X bump the VFO on TX so your audio always sits in the clean 1500–2000 Hz window — harmonics cannot sneak through the SSB filter. None is the splatter setting. This is independent of Hold Tx Freq, which parks your TX offset on the waterfall so you do not land on the activator.

Test at home: one QSO on each band you plan to use. Confirm frequency readout matches the VFO.

Time sync in the field

FT8 fails silently when the clock drifts.

Method	Notes
GPS + PPS dongle	Best for no-cell sites; BktTimeSync or vendor tool
Internet via phone hotspot	Quick check: decode others before you TX
WSJT-X “Sync PC clock to GPS”	When GPS hardware is present

If nobody decodes and you decode nobody, fix time before chasing RFI gremlins.

Activating with FT8

Frequency and clearance

Listen on the waterfall. Pick a clear slice. Do not transmit on top of an existing QSO.

POTA official guidance: use split behavior — activator on one frequency, hunters on another slot in the waterfall. In WSJT-X, Hold Tx Freq lets you park your TX on an open offset while decoding CQers elsewhere. Fake It / Rig (above) keeps that TX audio clean. Do not confuse the two: Fake It is the radio; Hold Tx Freq is the waterfall.

Do not put K-1234 in the comment in 2026. Current US references are US-####. The comment field is still free text — US-1412 or POTA US-1412. Spot the dial frequency (e.g. 14.074), not 14.074 plus the audio offset.

Calling CQ

Set mode FT8 (or FT4 for faster pileups — harsher on timing).
Enter your park reference in the free-text / comment field — WSJT-X has no dedicated POTA field. Example: US-1412 (not a stale K- number).
Optional Tx macro: CQ POTA YOURCALL US-1412
Enable TX, watch the waterfall fill.
Spot on pota.app with exact dial frequency and mode FT8. Refresh the spot every ~30 minutes or after QSY.

Warning: Do not spot a frequency you are not on. Do not use terrestrial repeaters. WSJT-X does not exempt you from QRL? and band plans.

Working hunters

Log each QSO in WSJT-X and your master logger (Polo / N3FJP) if you use one. WSJT-X ADIF alone is easy to upload but may lack MY_SIG_INFO unless you configure export or post-process with ADIF Doctor.
Dupes: same hunter, same band, same mode, same UTC day — one counts toward POTA minimums.
Different modes (FT8 then FT4 then PSK via FLdigi) can count as separate QSOs — confirm current program rules.

P2P on FT8

When both stations are in the field, park references belong in the exchange or comment field. Log their reference in SIG_INFO / Polo’s their-park field on that QSO. See ADIF parks.

Hunting with FT8

From the POTA hunter guide:

Do not transmit on the activator’s RX frequency. Use split / Hold Tx Freq; call on an open waterfall slot.
Skip sending your grid when hunting — saves time in the 15-second sequence.
Once you receive a signal report, log the contact even if you never get a final 73 in a busy pileup.
One call per slot. Let Auto Seq finish before calling again.

UDP and downstream loggers

Settings → Reporting → UDP Server:

Enable Accept UDP requests
Default 127.0.0.1:2237

GridTracker, JTAlert, and tools like Potatui ingest this stream. See GridTracker and JT Alert.

For Polo-centric workflows, many activators still hand-enter or import from WSJT-X ADIF at end of day — verify MY_SIG_INFO before upload.

End of activation

Follow Split logs, then Doctor. Short version:

Export / archive the WSJT ADIF.
Merge into Polo Full (or stamp the WSJT file) in ADIF Doctor.
Upload the POTA pack to pota.app if activating.
Recap from Full. Hunters: LoTW/QRZ if you chase awards — POTA hunter credit is activator-log-based.

Troubleshooting

Symptom	Likely cause
No decodes	Clock wrong, wrong band, antenna/system failure
Everyone “SNR -999”	Audio level — adjust RX/TX sliders and radio gain
RBN spots you on wrong freq	Dial frequency vs suppressed carrier — spot what hunters should tune
Laptop fan noise on RX	USB ground loop — ferrites, separate audio interface

Habits / gotchas / checklist (WSJT-X)

Fresh wsjtx_log.adi for this sitting. My Grid = field sheet, not home.
Clock within one second. GPS or hotspot NTP before Enable TX.
Split = Rig or Fake It. Hold Tx Freq on an open slot. Never TX on the activator’s tone.
USB-D, ALC just moving. DATA MOD matches the jack (7100 ACC vs 7300 USB).
Comment US-1412, not a stale K- number. Spot the dial frequency, mode FT8. Refresh ~30 min.
Skip sending hunter grid. Log after a report even without 73.
QRT: archive WSJT ADIF → merge with Polo Full in Doctor → POTA pack to pota.app. Recap from Full. One upload, not two overlapping files.

Software hub · GridTracker · JTAlert
Calling CQ · Hunt

Notes & edits

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